Clinical Anatomy Grant’s Dissector Notes (Summer 2009 and Summer 2010)
Melissa McDole
Unit 3—Dissector notes—Bold terms
THE ABDOMEN—Chapter 4
SURFACE ANATOMY—N247







Xiphoid process
Costal margin
Public symphysis
Pubic crest
Pubic tubercle
Anterior superior iliac spine
Tubercle of the iliac crest


Quadrant system: divides abdomen using transumbilical plane and medial plane
Regional system: divides abdomen based on right and left midclavicular lines, subcostal plane and the transtubercular plane
SUPERFIICAL FACIA OF THE ANTEROLATERAL ABDOMINAL WALL
Dissection Overview
 Abdominal cavity contents protected by anterolateral abdominal wall—many layers**--some layers include
o Superficial fatty layer(Camper’s fascia)—in superficial fascia
o Deep membranous layer: Scarpa’s fascia: continuous with fascias in perineum—N252
Superficial Fascia


Superficial epigastric artery and vein
Anterior cutaneous nerves
o Enter superficial fascia
o Branches of Intercostal nerves (T7 – T1), subcostal nerve (T12), iliohypogastric and ilioinguinal nerves (L1)—N164
 T7 innervates skin over the tip of the xiphoid process
 T10 innervates umbilicus skin
 T12 innervates skin superior to pubic symphysis
1
Clinical Anatomy Grant’s Dissector Notes (Summer 2009 and Summer 2010)
Melissa McDole

 L1 innervates skin over pubic symphysis—N257
Lateral cutaneous nerves
o Branches of intercostal nerves or subcostal nerves
Clinical Correlation**
 Superficial veins of abdominal wall
o Superficial epigastric vein anastomoses with lateral thoracic vein in superficial fascia
o Important collateral venous channel from the femoral vein to the axillary vein
o Obstruction of IVC or hepatic portal vein, results in superficial veins of abdominal wall being engorged and may be seen around
umbilicus—caput medusae
MUSCLES OF THE ANTEROLATERAL ABDOMINAL WALL
Dissection overview
 Three flat muscles (external oblique, internal oblique, and transversus abdominus) form most of anterolateral wall
 Each muscle contributes to formation of rectus sheath and inguinal canal
 Inguinal canal—in males
o Testes passing through abdominal wall during development drags its ductus deferens behind it—within canal
o Located superior to the medial half of the inguinal ligament—extends from superficial (external ) inguinal ring to the deep
(internal) inguinal ring
 Inguinal canal—in females
o Smaller diameter
 Contents in inguinal canal of male and females may differ
 Males:
o Spermatic cord
 Female
o Round ligament of the uterus
Skeleton of the abdominal wall—N248



Xiphisternal junction
Xiphoid process
Costal margin
2
Clinical Anatomy Grant’s Dissector Notes (Summer 2009 and Summer 2010)
Melissa McDole






Pubic symphysis
Pubic crest
Pubic tubercle
Anterior superior iliac spine
Iliac crest
Tubercle of the iliac crest
External Oblique Muscle—N249—Males (can use same dissection for females)









External oblique muscle
o Forms most superficial portion of inguinal canal
o Proximal attachment: external surfaces of ribs 5 to 12
o Distal attachment: linea alba, pubic tubercle, inferior half of iliac crest
o Fibers run from superolateral to inferomedial
Spermatic cord (males)—comes from superficial inguinal ring
Round ligament of the uterus (in females)—comes from superficial inguinal ring
o N249
Superficial inguinal ring
o Opening in external oblique aponeurosis
Lateral (inferior) crus
o Portion of external oblique aponeurosis that forms lateral margin of superficial inguina ring
o Attached to pubic tubercle
Medial (superior) crus
o Portion of external oblique aponeurosis that forms medial margin of superficial inguinal ring
o Attached to pubic crest
Intercrural fibers
o Span across crura superolateral to superficial inguinal ring
o Prevent crura from spreading apart
External spermatic fascia
o Thin layer of fascia extending from external oblique aponeurosis onto the spermatic cord or round ligament of the uterus
o Contribution of external abdominal oblique muscle to layers of spermatic cord
Ilioinguinal nerve
o Comes from inguinal canal at superficial inguinal ring
3
Clinical Anatomy Grant’s Dissector Notes (Summer 2009 and Summer 2010)
Melissa McDole


o Anterior to spermatic cord (or round ligament of the uterus)
o Gives sensory innervation fibers to the skin of the anterior surface of external genitalia and medial thigh
Inguinal ligament
o Inferior border of the aponeurosis of the external oblique muscle
o Vessels and nerves in abdominal cavity exist deep to inguinal ligament
Lacunar ligament—N258
o Formed by medial fibers of inguinal ligament
o Attach posteriorly to pectin pubis
Internal oblique muscle—N250







Internal oblique m. is deep to the external oblique m.
Internal oblique m. forms intermediate layer of inguinal canal
Internal oblique muscle
o Proximal attachment: thoracolumbar fascia, iliac crest and lateral half of inguinal ligament
o Distal attachment: inferior borders of ribs 10 – 12, linea alba, pubic crest, pectin pubis
N250
Cremaster muscle and fascia
o Lateral to the spermatic cord (or round ligament of the uterus)
o Muscle fibers connect internal oblique m. to spermatic cord (or round ligament)
o Contribution of internal oblique m. to the coverings of the spermatic cord
o In female: cremaster muscle and fascia surround round ligament of uterus
In intermuscular plane between external oblique and internal oblique mm can find 2 nerves
o Ilioinguinal n.
 Goes through inguinal canal and comes out at superficial inguinal ring
o Iliohypogastric nerve
 Runs parallel to ilioinguinal nerve and superior to it
Conjoint tendon
o Formation: Medial to superficial inguinal ring aponeurosis of internal oblique becomes fused with aponeurosis of transversus
abdominus muscle
Transversus abdominis muscle –N251

Transversus abdominis m.
4
Clinical Anatomy Grant’s Dissector Notes (Summer 2009 and Summer 2010)
Melissa McDole
o
o
o
o
o
Is deep to internal oblique muscle
Forms part of deepest layer of inguinal canal
Muscle fibers are similar to internal oblique m.
Proximal attachment: internal surfaces of costal cartilages 7 to 12, thoracolumbar fascia, iliac crest, lateral third of inguinal
ligament
Distal attachment: linea alba, pubic crest, pecten pubis—N251
Deep inguinal ring—N259




Transversalis fascia
o Lines inner surface of abdominis mm.
Deep inguinal ring
o Point where testis passes through transversalis fascia during development
o Superior to midpoint of inguinal ligament
o Marks deep extent of inguinal canal
o In males: ductus deferens passes through deep inguinal ring
o In females: round ligament of uterus passes through deep inguinal ring
Inferior epigastric vessels
o Within layer of extraperitoneal fascia
o Deep inguinal ring is lateral to inferior epigastric vessels—find ductus deferens (or round ligament of uterus) as reference
Boundaries of inguinal canal
o Deep: deep inguinal ring
o Superficial: superficial inguinal ring
o Anterior: aponeurosis of the external oblique muscle
o Inferior (floor): inguinal ligament and lacunar ligament
o Superior (roof): arching fibers of the internal oblique and transversus abdominis mm.
o Posterior: transversalis fascia, reinforced medially by conjoint tendon
Clinical correlation**---do later!!!
Inguinal hernias
 Inguinal canal is weak area of abdominal wall through which abdominal visceral may protrude (inguinal hernia)
 Different classifications
o Indirect inguinal hernia
5
Clinical Anatomy Grant’s Dissector Notes (Summer 2009 and Summer 2010)
Melissa McDole
o
 Exits abdominal cavity through deep inguinal ring lateral to the inferior epigastric vessels, and follows inguinal canal
Direct inguinal hernia
 Exists abdominal cavity medial to inferior epigastric vessels and follows a direct course through abdominal wall
Rectus abdominus muscle—N250





Rectus sheath
o Formed by aponeuroses of three flat abdominal muscles
o Contains
 Rectus abdominis m.
 Inferior attachment: symphysis and body of the pubis
 Superior attachment: costal cartilages of ribs 5 to 7
 Function: flexes trunk
 Innervation: terminal ends of ventral rami of spinal nerves T7 to T12
 Superior and inferior epigastric vessels
 Terminal ends of the ventral rami of spinal nerves T7 to T12
 Innervate rectus abdominis m. and emerge as anterior cutaneous branches –N257
 Pyramidalis m.
Tendinous intersections
N255
Superior epigastric artery and vein
o On superior half of rectus abdominis m.
Inferior epigastric artery and vein
o On inferior half of rectus abdominis m.
Clinical Correlation***
Epigastric Anastomoses
 Superior epigastric vessels anastomose with inferior epigastric vessels within rectus sheath
 If IVC is obstructed, anastomosis between the inferior epigastric and superior epigastric veins provides a collateral venous channel that
drains into the SVC
 If aorta is occluded, collateral arterial circulation to the lower part of the body occurs through the superior and inferior epigastric arteries
6
Clinical Anatomy Grant’s Dissector Notes (Summer 2009 and Summer 2010)
Melissa McDole





Arcuate line:
o On posterior wall of rectus sheath
o Located midway between pubic symphysis and umbilicus
o At this level, inferior epigastric vessels enter rectus sheath
Transversalis fascia
o Inferior to arcuate line
Parietal peritoneum
Linea alba
o In midline
o Formed by fusion of aponeuroses of right and left flat abdominal mm (external oblique, internal oblique, and transversus
abdominis)
Pyramidalis m.
o Anterior to inferior end of the rectus abdominis m.
o Frequently absent
o If present: attaches to anterior surface of the pubis and linea alba and draws down linea alba
REFLECTIONOF THE ABDOMINAL WALL
Dissection overview



Anterior abdominal wall will be incised and opened
Inner surface of anterior abdominal wall will be studied
Divided into quadrants

Falciform ligament
o On inner surface of RUQ flap
o Connects anterior abdominal wall to surface of liver –N253
Three folds on inner surface of lower abdominal wall:
o Median umbilical fold
 In midline inferior to the umbilicus
 Attached to RLQ flap,
 Contains urachus (obliterated allantoic duct)
o Medial umbilical fold
 Located lateral to median umbilical fold
7

Clinical Anatomy Grant’s Dissector Notes (Summer 2009 and Summer 2010)
Melissa McDole
o
o
 Contains the obliterated umbilical artery
Lateral umbilical fold
 Located lateral to medial umbilical fold
 Overlies the inferior epigastric artery and vein
Deep inguinal ring
 Small depression located lateral to lateral umbilical fold
PERITONEUM AND PERITONEAL CAVITY
Dissection overview

In abdominal cavity and pelvic cavity, membrane lined by serous fluid that lubricate organ movements = peritoneum
o Two types of peritoneum
 Parietal peritoneum
 Lines inner surfaces of abdominal and pelvic walls
 Visceral peritoneum
 Covers surfaces of abdominal and pelvic organs
 Peritoneal cavity
 Space between parietal and visceral peritoneum
 Potential space
o Intraperitoneal (peritoneal) organs
 Some examples include: stomach, small intestine, liver, and spleen
o Retroperitoneal (extraperitoneal) organs
 Some examples include: ureters, suprarenal glands, kidneys
o Secondarily retroperitoneal
 Duodenum, pancreas, ascending colon, descending colon
Abdominal Viscera—N269


Gastrointestinal tract
Liver
o Intraperitoneal organ
o Occupies RUQ and extends across midline into LUQ
o Lies against inferior surface of diaphragm
8
Clinical Anatomy Grant’s Dissector Notes (Summer 2009 and Summer 2010)
Melissa McDole






o Attachment of falciform ligament divides liver into right and left lobes
Gallbladder
o Intraperitoneal organ
o In RUQ
o Extends below inferior border of liver
o Found at tip of right 9th costal cartilage in midclavicular line
Stomach
o Intraperitoneal organ
o ULQ
o Continuous with esophagus proximally and duodenum distally
o Liver partial covers anterior surface of stomach
Spleen
o Intraperitoneal organ
o In LUQ
o Found posterior to stomach
Greater omentum
o Attached to the greater curvature of the stomach
Small intestine
o Begins at pyloric end of the stomach
o Has 3 parts
 Duodenum
 Most is secondarily retroperitoneal
 Jejunum
 Intraperitoneal organ that extends from LUQ to RLQ—occupy all 4 quadrants
 Ileum
 Intraperitoneal organ that extends from LUQ to RLQ—occupy all 4 quadrants
Large intestine
o Begins in RLQ at the ileocecal junction
o Has 6 parts
 Cecum: located in RLQ
 Appendix is attached to the inferior end of the cecum
 Ascending colon:
 Extends from RLQ to the RUQ
9
Clinical Anatomy Grant’s Dissector Notes (Summer 2009 and Summer 2010)
Melissa McDole




 Ends at the right colic (hepatic) flexure
 Is secondarily retroperitoneal
Transverse colon
 Extends from RUQ to the LUQ
 Ends at the left colic (splenic) flexure
 Is intraperitoneal
Descending colon
 From LUQ to the LLQ
 Secondarily retroperitoneal
Sigmoid colon
 In LLQ
 Ends in pelvic cavity at the level of the third sacral vertebral level
 Intraperitoneal organ
Rectum
 Located in the pelvis
Peritoneum—N269




Visceral peritoneum:
o On surface of stomach or small intestine
o Smooth and slippery surface
Parietal peritoneum
o Inner surface of abdominal wall
o Surface is smooth and slippery
Greater omentum—N275
o Normally lies between intestines and anterior abdominal wall
Lesser omentum
o Passes from lesser curvature of stomach to first part of duodenum to inferior surface of the liver
o Has 2 parts
 Hepatogastric ligament:
 Extends from liver to the lesser curvature of the stomach
 Hepatoduodenal ligament
 Extends from the liver to the 1st part of the duodenum
10
Clinical Anatomy Grant’s Dissector Notes (Summer 2009 and Summer 2010)
Melissa McDole













Falciform ligament
o Passes from the parietal peritoneum on anterior abdominal wall to the visceral peritoneum on surface of the liver
Round ligament of the liver (ligamentum teres hepatis)
o Obliterated umbilical vein
o Found in inferior free margin of falciform ligament
Coronary ligament
o Attaches liver to diaphragm
o 2 additional peritoneal ligaments
 Left triangular ligament
 Between left lobe of liver and diaphragm
 Right triangular ligament
 Between right lobe of liver an diaphragm
Gastrophrenic ligament
o Connects superior part of greater curvature of the stomach to the diaphragm
Gastrosplenic (gastrolienal) ligament
o From greater curvature of stomach to the spleen
Splenorenal (lienorenal) ligament
o Connects spleen to posterior abdominal wall over the left kidney
Transverse mesocolon
o Attaches the transverse colon to the posterior abdominal wall
Phrenicocolic ligament
o At left end of the transverse mesocolon
o Attaches the left colic flexure to the diaphragm—N271
Mesentery
o Suspends jejunum and ileum from posterior abdominal wall
o Root of mesentery attaches to posterior abdominal wall from LUQ to the RLQ
Mesoappendix
o Attaches the appendix o the posterior abdominal wall and it contains the appendicular artery
Sigmoid mesocolon
o In LLQ
o Suspends sigmoid colon from posterior abdominal wall
Greater peritoneal sac
Lesser peritoneal sac (omental bursa)
11
Clinical Anatomy Grant’s Dissector Notes (Summer 2009 and Summer 2010)
Melissa McDole


o Posterior to stomach and lesser omentum
Omentum foramen (epiploic foramen)
o Connects greater and lesser peritoneal sacs
o Is posterior to hepatoduodenal ligament—N275
o Has 4 boundaries
 Anterior:
 Hepatic portal vein
 Hepatic artery proper
 Bile duct contained within hepatoduodenal ligament
 Posterior:
 IVC and right crus of diaphragm covered with parietal peritoneum
 Superior:
 Caudate lobe of the liver covered with visceral peritoneum
 Inferior:
 First part of duodenum covered with visceral peritoneum
Lesser peritoneal sac
o Inferior recess
 Lowest part of sac
 Extends inferiorly as far as the greater omentum
 During development, inferior recess extended between layers of greater omentum
o Superior recess
 Highest part of lesser peritoneal sac
 Diaphragm lies posterior to it
 Caudate lobe of liver is anterior to it—N172
CELIAC TRUNK, STOMACH, SPEEN, LIVER, AND GALLBLADDER

Parts of the stomach—N275
o Anterior surface
o Greater curvature
o Lesser curvature
o Cardia
o Cardial notch
o Fundus
12
Clinical Anatomy Grant’s Dissector Notes (Summer 2009 and Summer 2010)
Melissa McDole

o Body
o Angular incisure (notch)
o Pyloric part
o Pylorus
Features of liver –N287
o Right lobe
o Left lobe
o Diaphragmatic surface
o Inferior border
 Visceral surface of the liver
 Is in contact with the gallbladder and peritoneum covering stomach, duodenum, colon, right kidney, and right
suprarenal gland
 Porta hepatis
o Fissure through which vessels, ducts, lymphatics, and nerves enter the liver—N287
 Gallbladder
Celiac trunk—N301
**Arteries are named by their region of distribution, not by their origin or branching pattern






Hepatoduodenal ligament
o Bile ducts (1)
 Most lateral of the 3
o Hepatic artery proper (2)
o Hepatic portal vein (3)
o Autonomic nerves
o Lymphatics
Cystic duct
Common hepatic duct
Right hepatic duct
Left hepatic duct
o Porta hepatic: where right and left hepatic ducts exit
Hepatic artery proper
o Contains the autonomic nerve plexus—N300
13
Clinical Anatomy Grant’s Dissector Notes (Summer 2009 and Summer 2010)
Melissa McDole
o
o
o


Left hepatic artery
Right gastric artery
Right hepatic artery
 Cystic artery
 From right hepatic artery
 Goes to gallbladder
Lymphatics
o Contained in hepatoduodenal ligament
o Hepatic lymph nodes
Common hepatic artery
o Can find by following hepatic artery proper inferiorly
o Gives rise to gastroduodenal artery
 Passes posterior to the first part of the duodenum
 Divides to give rise to the right gastro-omental (gastroepiploic) artery and the anterior superior
pancreaticoduodenal artery
**Clinical correlation
Anatomical variation in Arteries






About 12% of cases have hepatic artery arising from the SMA
Left hepatic artery may arise from left gastric artery
During surgical removal of the stomach (gastrectomy), blood flow to left hepatic artery could be interrupted, endangering left lobe of the
liver
Cystic artery usually arises from the right hepatic artery, but other origins possible
Cystic artery may pass posteriorly (75%) or anterior (24%) to the common hepatic duct
Celiac trunk
o Arises from anterior surface of abdominal aorta at the level of the 12th thoracic vertebra
o Very short
o Divides into three branches
 Common hepatic artery
 Left gastric artery
 Goes to stomach near esophagus
14
Clinical Anatomy Grant’s Dissector Notes (Summer 2009 and Summer 2010)
Melissa McDole




 Follows curvature of the stomach within the lesser omentum
 Forms an anastomosis with the right gastric artery along the lesser curvature of the stomach
 Branches distribute to anterior and posterior surfaces of the stomach
 Splenic artery
 Lies against the posterior abdominal wall
 Courses along superior border of the pancreas
Short gastric arteries
o From splenic artery to supply fundus of stomach
Left gastro omental (gastroepiploic) artery
o From greater curvature of stomach
o Branch of splenic artery
Right gastro-omental artery
o In greater omentum near right end of greater curvature of stomach
o Anastomoses with left gastro-omental artery—N301
Hepatic portal vein
o Posterior to hepatic artery proper and bile duct
o Passes into porta hepatis superiorly and divides into:
 Right and left portal veins
 Receives left and right gastric veins
 Inferiorly: passes posterior to first part of duodenum
Spleen—N299
Largest hematopoietic organ in the body
Covered by visceral peritoneum except at the hilum where splenic vessels enter and leave


Visceral surface of spleen is related to 4 organs:
o Stomach
o Left kidney
o Transverse colon (left colic flexure)
o Pancreas
Diaphragmatic surface of spleen is related (through the diaphragm) to ribs 9, 10, and 11
15
Clinical Anatomy Grant’s Dissector Notes (Summer 2009 and Summer 2010)
Melissa McDole
**Clinical Correlation
Spleen
 Relationship of the spleen to ribs 9, 10 and 11 is of clinical importance in evaluating rib fractures and penetrating wounds
 A lacerated spleen bleeds profusely into the abdominal cavity and may be removed surgically
 Risk of puncturing spleen during pleural tap (thoracocentesis)
 Enlarge spleen (splenomegaly) may be observed during physical exam
o It is enlarged when it can be palpated inferior to the costal margin
Liver—287

Liver:
o
o
o
o
o
o
o
o
o
o
Largest gland in body
2.5% of body weight
Right lobe: six times larger than left lobe
Left lobe
Inferior border of liver separates visceral surface from diaphragmatic surface
Bare area
 Posterior aspect of diaphragmatic surface
 Liver was adjacent to diaphragm and not covered by peritoneum in this region
 Coronary ligament
Visceral surface: has H-shaped set of fissure and fossae defining 4 lobes
 Right lobe
 Left lobe
 Caudate lobe
 Quadrate lobe—N287
 Ligamentum venosum and falciform ligament occupy the left fissure of the H
 Gallbladder and IVC occupy the fossae that form the right side of the H
 Porta hepatis: forms horizontal bar of H
IVC: small part attaches to liver; where hepatic veins drain
Falciform ligament divides liver into right and left anatomical lobes
 Right and left functional lobes—N289
Hepatic lymph nodes
16
Clinical Anatomy Grant’s Dissector Notes (Summer 2009 and Summer 2010)
Melissa McDole
o
Celiac lymph nodes
**Clinical Correlation
Liver
 Liver may be enlarged due to liver congestion due to cardiac insufficiency (cardiac liver)
 Liver may be small and have fibrous nodules—may indicate cirrhosis of the liver
 May have metastatic tumor cells trapped in capillary beds—resulting in secondary tumors
Gallbladder—N294
 Used for storage and concentration of bile
 Occupies a shallow fossa on visceral surface of the liver
 Parts:
o Neck
o Body
o Fundus
 Cystic artery
 Spiral fold
 Cystic duct
SUPERIOR MESENTERIC ARTERY AND SMALL INTESTINE
Superior mesenteric artery—N306



Comes from anterior surface of abdominal aorta lies posterior to neck of pancreas passes anterior to uncinate process third part of
duodenum  left renal vein mesentery courses toward terminal end of ileum
Jejunum and ileum
Superior mesenteric artery
o Branches:
 Inferior pancreaticoduodenal artery
 First branch
17
Clinical Anatomy Grant’s Dissector Notes (Summer 2009 and Summer 2010)
Melissa McDole




Intestinal arteries
 15 – 18 arteries to jejunum and ileum
 End in straight terminal branches called vasa rectae
 Arcades connect intestinal arteries
 Ileocolic artery
 Right colic artery
 Middle colic artery
Superior mesenteric plexus of nerves
Branches of superior mesenteric artery
o Inferior pancreaticoduodenal artery
 First branch of SMA
o Intestinal arteries
 15 – 18 arteries to the jejunum and the ileum
 End in straight terminal branches called vasa recta
 Arcades connect the intestinal arteries
 Supplies blood to proximal jejunum
 Long vasa recta are characteristic of blood supply to jejunum—many arcades
 Short vasa recta are characteristic of blood supply to the ileum—few arcades
o Ileocolic artery
 Supplies cecum
 Gives rise to appendicular artery
 Anastomoses with the intestinal branches and with the right colic artery
o Right colic artery
 Supplies the ascending colon
 Arises from right side of SMA and passes to right in a retroperitoneal position
 Divides into superior branch and inferior branch
o Middle colic artery
 Supplies transverse colon
 Arises from anterior surface of SMA and courses through transverse mesocolon
 Divides into a right and left branch
Superior mesenteric vein
o Courses along right side of SMA
o Formed by branches that correspond in name and position to the branches of the SMA
o Posterior to pancreas, the SMV joins splenic vein tor for the hepatic portal vein
18
Clinical Anatomy Grant’s Dissector Notes (Summer 2009 and Summer 2010)
Melissa McDole


Mesenteric lymph nodes
Superior mesenteric lymph nodes
o Located near origin of SMA from abdominal aorta
Small Intestine—N270








Parts
o Duodenum, jejunum (proximal 2/5), ileum (distal 3/5)
Function
o Absorbs nutrients from food
o The folds of mucosa increase surface area
o Its rich blood supply transport absorbed nutrients
Duodenojejunal junction
Suspensory ligament of the duodenum
o Fibromuscular ligament that arises from the right crus of the diaphragm and anchors the intestine at the duodenojejunal junction
Wall of jejunum is thicker than the wall of the ileum
Ileum empties into the cecum at the ileocecal junction
Root of the mesentery
o Crosses the posterior abdominal wall from the duodenojejunal junction to the ileocecal junction
Intestinal attachment of the mesentery
INFERIOR MESENTERIC ARTERY AND LARGE INTESTINE

Inferior mesenteric artery
o Arises from anterior surface of the abdominal aorta at the level of L2 and L3
o Supplies left half of transverse colon, descending colon, sigmoid colon, and most of the rectum
o Retroperitoneal
Inferior Mesenteric Artery—N307

Branches of the inferior mesenteric artery
o Left colic artery
 Supplies descending colon and left third of transverse colon
19
Clinical Anatomy Grant’s Dissector Notes (Summer 2009 and Summer 2010)
Melissa McDole
 Left colic artery anastomoses with the middle colic branch of the SMA
Sigmoid arteries
 Three or four arteries that supply sigmoid colon
 Pass through sigmoid mesocolon
 Form arcades also—similar to intestinal arteries
o Superior rectal artery
 Supplies proximal part of rectum
 Divides into a right and left branch which descend into the pelvis on either side of rectum
Inferior mesenteric vein
o Tributaries of the IMV correspond to the branches of the IMA
o Tributary of the hepatic portal vein
o Ascends on the left side of the IMA and passes posterior to the pancreas, joins either the splenic vein or the superior mesenteric
vein
Inferior mesenteric nodes
o


Large Intestine—N284






Parts
o Cecum (with attached appendix)
o Colon (ascending, transverse, descending and sigmoid)
o Rectum
o Anal canal
Function
o Absorbs water from fecal material
o Has smooth mucosal surface
Cecum
o In RLQ
Appendix (vermiform appendix)
o Attached to end of cecum
o Suspended on mesentery called mesoappendix
o Appendicular artery: found within the mesoappendix
Ascending colon
o Extends from cecum to right colic flexure
Transverse colon
20
Clinical Anatomy Grant’s Dissector Notes (Summer 2009 and Summer 2010)
Melissa McDole




o Extends from right colic flexure to the left colic flexure
o Left colic flexure has a more superior level than the right colic flexure
o Transverse colon freely moves between the two flexures
Descending colon
o Secondarily retroperitoneal organ
o Descends from the left colic flexure to the LLQ
Sigmoid colon
o In LLQ
o Has mesentery (sigmoid mesocolon) and is mobile
o Ends in pelvis at S3 and becomes continuous with rectum
Rectum
o All contained in pelvic cavity
Three features of the external surface of the large intestine that distinguish it from the small intestine
o Teniae coli—three narrow bands of longitudinal muscle
o Haustra—outpouchings of the wall of the colon
o Omental appendices (epiploic appendages)—small accumulations of fat covered by visceral peritoneum
N307
DUODENUM, PANCREAS, AND HEPATIC PORTAL VEIN


Duodenum (part of small intestine) is between the stomach and jejunum
o Is the drainage point for ducts of liver and pancreas
o Pancreas lies within bend of duodenum
Pancreas is both an endocrine and exocrine organ
o Has a rich blood supply from the celiac trunk and the SMA
Duodenum—N278

Four parts of the duodenum
o Superior (first) part
 At level L1
 Lies in transverse plane
 Hepatoduodenal ligament attaches to it
21
Clinical Anatomy Grant’s Dissector Notes (Summer 2009 and Summer 2010)
Melissa McDole
o
o
o
 Mostly intraperitoneal
Descending (second) part
 At L2
 To right of midline and anterior to right kidney, right renal vessels, and IVC
 Retroperitoneal
 Bile duct and pancreatic duct drain into descending part of duodenum
Horizontal (third) part
 At L3
 Is anterior to IVC and abdominal aorta
 Is retroperitoneal
 Is crossed anteriorly by superior mesenteric vessels and posteriorly by inferior mesenteric vessels
Ascending (fourth) part
 Ascends to level of L2
 Mostly retroperitoneal
 Joins jejunum at duodenojejunal junction anteriorly
Pancreas—N298

Pancreas
o Within bend of duodenum
o Secondarily retroperitoneal
o At L1 – L3
o Parts
 Head
 Lies in curve of duodenum
 Uncinate process—small projection from inferior margin of head that passes posterior to superior mesenteric
vessels
 IVC is posterior to the head of the pancreas
 Neck
 Short portion that is anterior to the superior mesenteric vessels and connects the head of the pancreas to the body
 Body
 Extends from right to left and slightly superiorly as it crosses the posterior abdominal wall
 Abdominal aorta lies posterior to the body
 Tail
22
Clinical Anatomy Grant’s Dissector Notes (Summer 2009 and Summer 2010)
Melissa McDole
o
o
o
o
o
o
o
o
 Narrow end of gland
 Tip of tail is in the splenorenal ligament and contacts the hilum of the spleen
Main pancreatic duct
 Goes from head to neck to body of pancreas
 Joined by the bile duct
 Goes toward descending part of duodenum
Accessory pancreatic duct
 Joins the superior side of the main pancreatic duct
Posterior superior and anterior superior pancreaticoduodenal arteries
 Branches of gastroduodenal artery—N301
Inferior pancreaticoduodenal artery
 Usually the most proximal branch of SMA
 Enters inferior portion of head of pancreas
Splenic artery branches supplying the pancreas (identify 2)
 Dorsal pancreatic artery—enters the neck of the pancreas
 Greater pancreatic (pancreatica magna) artery—enters pancreas at junction of medial 2/3 and lateral 1/3 of gland
Left gastro-omental artery
 Goes through greater omentum to anastomose with the right gastro-omental artery
 Comes off splenic artery
Veins of pancreas correspond to the arteries of the pancreas
Veins drain into SMV and splenic veins then eventually drain to hepatic portal vein
Hepatic Portal Vein—N311





Superior mesenteric vein and splenic vein join to form the hepatic portal vein posterior to the neck of the pancreas
Hepatic portal vein—carries venous blood to the liver from the abdominal portion of the GI tract, spleen and the pancreas
Splenic vein
o Courses posterior to pancreas, inferior to splenic artery
o Following splenic vein to the right it joins the SMV—origin of the hepatic portal vein (ascends in the hepatoduodenal ligament
to the porta hepatis)
The IMV may join the splenic vein or the SMV or the junction of the SMV and splenic veins
Portal-systemic (portal-caval) anastomoses::
o Gastroesophageal—left gastric vein/esophageal veins/azygos vein
o Anorectal—superior rectal vein/middle and inferior rectal veins
23
Clinical Anatomy Grant’s Dissector Notes (Summer 2009 and Summer 2010)
Melissa McDole
o
o
Paraumbilical—paraumbilical veins/superficial epigastric veins
Retroperitoneal—colic veins/retroperitoneal veins
**Clinical Correlation
Portal Hypertension
 Hepatic portal system of veins have no valves
 When hepatic portal vein is blocked, blood pressure increases in the hepatic portal system (portal hypertension) and its tributaries become
engorged
 Causes hemorrhoids and varicose gastric and esophageal veins
 Bleeding from ruptured gastroesophageal varices is a dangerous complication of portal hypertension
REMOVAL OF THE GASTROINTESTINAL TRACT





Stomach interior-N276
o Gastric folds (rugae)
o Pyloric antrum
o Pyloric canal
o Pyloric sphincter
o Pyloric orifice
2nd part of duodenum—N279
o Circular folds (plicae circulares)
o Major (greater) duodenal papilla
 Elevation of mucosa on medial wall of second part of duodenum
 Shared opening of the main pancreatic duct and bile duct
o Minor (lesser) duodenal papilla
 Site of drainage of accessory pancreatic duct
Proximal jejunum—N280
o Circular folds are larger and closer together in jejunum
Distal ileum
Cecum—N282
o Ileocecal orifice
o Superior and inferior lips of the ileocecal valve
o Opening of the appendix
24
Clinical Anatomy Grant’s Dissector Notes (Summer 2009 and Summer 2010)
Melissa McDole

Transverse colon
o Semilunar folds (plicae semilunares)
o Haustra—N284
POSTERIOR ABDOMINAL VISCERA


Posterior abdominal viscera are located in the retroperitoneal space (not a real space)—part of the body between the parietal peritoneum
and the muscles and bones of the posterior abdominal wall
Retroperitoneal space contains –N342
o Kidneys
25
Clinical Anatomy Grant’s Dissector Notes (Summer 2009 and Summer 2010)
Melissa McDole





o Ureters
o Suprarenal glands
o Aorta
o IVC
o Abdominal portions of sympathetic trunks
Kidneys and suprarenal (adrenal) glands—N329
o Lie lateral to the vertebral column at T12 – L3 level
Testicular artery and vein
o At the deep inguinal ring
o Small and delicate
o Cross anterior to the ureter
Right and left testicular arteries
o Branch directly from aorta at L2
o Origin is inferior to the origin of the renal arteries
Left testicular veins drains into the left renal vein
Right testicular veins drains directly into the IVC
**Clinical Correlation
Testicular Varicocele


Varicocele is a varicose condition of the pampiniform plexus of veins
More common on left side because left testicular vein drains into the left renal vein—left renal vein can be compressed where it passes
inferior to the SMA

In female
o Ovarian vessels
 Cross anterior to the ureter
 Inferiorly, vessels end in pelvic cavity
 Cross external iliac vessels
Kidneys—N329


Kidneys lie against posterior abdominal wall
Anterior surface of kidney faces anterolaterally
26
Clinical Anatomy Grant’s Dissector Notes (Summer 2009 and Summer 2010)
Melissa McDole









N329


Kidney
Perirenal fat
Renal fascia
Superior pole of kidney
o Separated from suprarenal gland by a thin layer of renal fascia
Left renal vein
o From kidney to IVC
o Crosses anterior to the renal arteries and aorta
o Tributaries
 Left testicular (or ovarian) vein
 Left suprarenal vein
Left renal artery
o Posterior to the left renal vein
o Goes to the hilum of the kidney
o Divides before it enters the kidney, and accessory renal arteries are common
Renal pelvis
Ureter
Right renal artery
o Lies posterior to the right renal vein and IVC
o Longer than the left renal artery
o Lies posterior to the right renal artery
Relationships of the kidneys
o Suprarenal gland is superior to kidney
o Right kidney is in contact with right colic flexure, visceral surface of liver, and the second part of the duodenum
o Left kidney is in contact with the tail of the pancreas, the left colic flexure, stomach, and spleen
Within split halve of the kidney—N334
o Renal capsule—fibrous capsule that can be stripped off surface of kidney
o Renal cortex—outer zone of kidney (1/3 in depth)
o Renal medulla—inner zone of kidney
 Contains renal pyramids and renal columns
o Renal sinus—space within kidney that is occupied by renal pelvis, calices, vessels, nerves, and fat
27
Clinical Anatomy Grant’s Dissector Notes (Summer 2009 and Summer 2010)
Melissa McDole
o
o
o
o
o
Renal papilla—apex of renal pyramid that projects into minor calyx
Minor calyx—cup-like chamber that is the beginning of the extrarenal duct system—several combine to form a major calyx
Major calyx—2 or 3 per kidney that combine to form the renal pelvis
Renal pelvis—funnel-like end of the ureter that lies within the renal sinus
Ureter—the muscular duct that carries urine from the kidney to the urinary bladder
Clinical Correlation
Kidney Stones
 Kidney stones (renal calculi) may form in calyces and renal pelvis
 Small stones may pass through ureter to the bladder
 Larger stones may pass at one of three natural constrictions of the ureter
o Where the renal pelvis joins the ureter
o Where the ureter crosses the pelvic brim
o At the entrance of the ureter into the urinary bladder
Suprarenal glands—N332







Suprarenal (adrenal) glands
o Highly vascularized endocrine organs
Right suprarenal gland
o Triangular
o Part of it lies posterior to IVC
Left suprarenal gland
o Semilunar
Suprarenal arteries
o Superior suprarenal arteries—from inferior phrenic artery
o Middle suprarenal artery—from aorta near celiac trunk
o Inferior suprarenal artery—from renal artery
Left suprarenal vein empties into left renal vein
Right suprarenal vein drains into IVC
Suprarenal glands receive many sympathetic nerve fibers
Clinical Correlation
Suprarenal glands
28
Clinical Anatomy Grant’s Dissector Notes (Summer 2009 and Summer 2010)
Melissa McDole


Kidneys and suprarenal glands have different embryonic origins
If kidney fails to ascend to its normal position during development, the suprarenal gland develops in normal position lateral to the celiac
trunk
Abdominal Aorta and IVC—N329




Adnominal aorta has three types of branches
o Unpaired arteries to GI tract
 Celiac trunk
 SMA
 IMA
o Paired arteries to the three paired abdominal organs
 Suprarenal
 Renal
 Testicular
 Ovarian arteries
o Paired arteries to abdominal wall
 Inferior phrenic
 Lumbar
 Four pairs supply the posterior abdominal wall
 Pass deep to the psoas major muscle
Bifurcation of abdominal aorta
o At L4
o Umbilicus may project superior to bifurcation of aorta
Common iliac arteries
o From bifurcation of aorta
o Supplies blood to pelvis and lower limbs
IVC
o Has no unpaired visceral tributaries because the hepatic portal system collects blood from the GI tract; hepatic portal veinliver;
hepatic veins drain IVC
POSTERIOR ABDOMINAL WALL

Psoas major m.
29
Clinical Anatomy Grant’s Dissector Notes (Summer 2009 and Summer 2010)
Melissa McDole





o Proximal attachment: lumbar vertebrae (bodies, IV discs, transverse processes)
o Distal attachment: lesser trochanter of the femur
o Function: strong flexor of thigh and vertebral column—N263
Psoas minor m.
o Is absent in approx 40% of cases—may be present on one side of cadaver
o Has long thin flat tendon passing down the anterior surface of the psoas major muscle
o Distal attachment: iliopubic eminence and arcuate line of the ilium
Iliacus m.
o Proximal attachment: iliac fossa
o Distal attachment: lesser trochanter of the femur
o Function: flexes the thigh
Iliopsoas m.
o Made up of iliacus m. and psoas major m.
Quadratus lumborum m.
o Proximal attachment: 12th rib and lumbar transverse processes
o Distal attachment: iliolumbar ligament and iliac crest
o Function: flexes vertebral column laterally; anchors inferior end of rib cage during respiration
Transversus abdominis m.
o Forms lateral part of posterior abdominal wall
o Is posterior to the quadratus lumborum m.
** The superior pole of the right kidney is at level of the 12th rib; the superior pole of the left kidney is slightly higher at the 11th rib
Lumbar Plexus—N267


Ventral rami of spinal nerves T12 to L4= nerves of posterior abdominal wall
Lumbar plexus (L1 to L4)
o Formed within psoas major m.
o Branches seen from lateral border of muscle
o Genitofemoral nerve
 On anterior surface of psoas major m.
 Motor nerve to cremaster m. (genital part)
 Supplies small area of skin inferior and medial to the inguinal ligament (genital and femoral parts)
 Two parts of nerve divide on anterior surface of psoas major m. superior to the inguinal ligament
30
Clinical Anatomy Grant’s Dissector Notes (Summer 2009 and Summer 2010)
Melissa McDole
o
o
o
o
o
o
Subcostal nerve
 Located 1 cm inferior to 12 rib
Iliohypogastric and ilioinguinal nerves
 Descend steeply across anterior surface of quadratus lumborum m.
 Arise from a common trunk
 Don’t separate until they reach transversus abdominis m.
Lateral cutaneous nerve of the thigh
 Passes deep to the inguinal ligament near the anterior superior iliac spine
 Supplies skin on the lateral aspect of the thigh
Femoral nerve
 Lies on lateral side of psoas major m. in groove between the psoas major and iliacus mm.
 Innervates psoas major and iliacus mm
 Passes deep to inguinal ligament and provides motor and sensory branches to anterior thigh
Obturator nerve
 Supplies motor and sensory innervation to the medial thigh
Lumbosacral trunk
 Large nerve formed by contribution from ventral ramus of L4 and all of the ventral ramus of L5
 Passes into pelvis to join sacral plexus
Abdominal part of sympathetic trunk—N318



Sympathetic trunk
o On transverse section of abdomen
o On vertebral body between crus of diaphragm and psoas major m.
Lumbar splanchnic nerves
o Pass anteriorly from sympathetic trunk to the aortic autonomic nerve plexus
Rami communicantes
o Pass posteriorly from sympathetic ganglia to lumbar ventral rami
o Each passes deeply between psoas major m. and vertebral body
o Gray rami of lower lumbar region are longest in body because the sympathetic trunk crosses the anterolateral surface of the
lumbar vertebral bodies
DIAPHRAGM
31
Clinical Anatomy Grant’s Dissector Notes (Summer 2009 and Summer 2010)
Melissa McDole

Diaphragm
o Forms roof of abdominal cavity and floor of thoracic cavity
o Muscle of respiration
o Has right half and left half—hemidiaphragms
N263







Parts of diaphragm
o Central tendon—aponeurotic center of diaphragm, which is the distal attachment of all of the muscular parts
o Sternal part- two small bundles of muscle fibers that attach to the posterior surface of the xiphoid process
o Costal part—muscle fibers that attach to the inferior six ribs and their costal cartilages
o Lumbar part—formed by 2 crura( right and left)
Right crus
o Proximal attachment: bodies of vertebrae L1 to L3
o Esophageal hiatus: is the opening in the right crus
Left crus
o Proximal attachment: bodies of vertebrae L1 to L2
Arcuate ligaments
o Thickenings of fascia that are proximal attachments for some of the muscle fibers of the diaphragm
 Lateral arcuate ligament: bridges anterior surface of quadratus lumborum m.
 Medial arcuate ligament: bridges the anterior surface of the psoas major m.
 Median arcuate ligament: (unpaired) bridges the anterior surface of the aorta at the aortic hiatus
Three large openings of diaphragm
o Vena caval foramen—passes through central tendon (T8)
o Esophageal hiatus—passes through the right crus (T10)
o Aortic hiatus—passes behind diaphragm (T12)
Right and left phrenic nerves
o Innervate diaphragm (C3, 4, 5)
o Provides motor innervation to one half of diaphragm
o Supply most of sensory innervation to abdominal (parietal peritoneum) and thoracic (parietal pleura) surfaces of diaphragm
The pleural and peritoneal coverings of peripheral part of diaphragm receive sensory fibers from lower intercostal nerves (T5 to T11) and
subcostal nerve
Clinical Correlation
Diaphragm
32
Clinical Anatomy Grant’s Dissector Notes (Summer 2009 and Summer 2010)
Melissa McDole




Phrenic nerve from C3, 4, 5)
Pain from diaphragm is referred to the shoulder region (supraclavicular nerve territory)
Is paralyzed in cases of high cervical spinal cord injuries, but is spared in low cervical spinal cord injuries
A paralyzed hemidiaphragm cannot contract (descend), so it will appear high in the thorax on a chest radiograph

Greater splanchnic nerve—N267
o Goes to superior surface of diaphragm
o Penetrates crus to enter abdominal cavity
o Distributes to celiac ganglion where sympathetic axons will synapse
o Innervates suprarenal gland
Celiac ganglion
o Found on left and right sides of celiac trunk near its origin from aorta
o Largest sympathetic ganglia that are located on the surface of the aorta

33
Clinical Anatomy Grant’s Dissector Notes (Summer 2009 and Summer 2010)
Melissa McDole
THE PELVIS AND PERINEUM—CHAPTER 5






Pelvis is transition between trunk and lower limbs
Pelvic cavity continuous with abdominal cavity—transition occurs at plane of pelvic inlet
Pelvic cavity contains
o Rectum
o Urinary bladder
o Internal genitalia
Perineum is region of trunk located between the thighs
Pelvic diaphragm
o Separates pelvic cavity from perineum
Perineum contains
o Anal canal
o Urethra
o External genitalia (penis, scrotum—male; vulva—female)
SKELETON OF THE PELVIS


Pelvis—formed by two hip bones (os coxae) joined posteriorly by sacrum
o each hip bone is formed by three fused bones: pubis, ischium, and ilium
 3 bones fuse at acetabulum
o Coccyx—attached to the sacrum—N353
Hip bone—N352
o Iliac fossa
o Iliopubic eminence
o Arcuate line
o Pecten pubis
o Superior pubic ramus
o Pubic symphysis
o Pubic arch
o Ischiopubic ramus—formed by ischial ramus and inferior pubic ramus
34
Clinical Anatomy Grant’s Dissector Notes (Summer 2009 and Summer 2010)
Melissa McDole










o Obturator foramen
o ischial tuberosity
o ischial spine
on sacrum find:--N353
o sacral promontory
o anterior sacral foramina
coccyx
the hip bone and the sacrum are connected by strong ligaments:
o N352
o Sacrotuberous ligament
o Sacrospinous ligament
o Greater sciatic foramen
o Lesser sciatic foramen
 The sacrotuberous ligament and sacrospinous ligament convert the greater and lesser sciatic notches into the greater
and lesser sciatic foramina
Anterior sacroiliac ligament
Posterior sacroiliac ligament
Iliolumbar ligament
Pubic arch
Subpubic angle—is wider in females than males—N354
Pelvic inlet (superior pelvic aperture)
o Bony rim of pelvic inlet is called the pelvic brim
 From anterior to posterior locate structures that form pelvic brim:--N353
 Superior margin of pubic symphysis
 Posterior border of pubic crest
 Pecten pubis
 Arcuate line of the ilium
 Anterior border of the ala (wing) of the sacrum
 Sacral promontory
Pelvic outlet
o Bounded on each side by:--N352
 Inferior margin of the pubic symphysis
 Ischiopubic ramus
35
Clinical Anatomy Grant’s Dissector Notes (Summer 2009 and Summer 2010)
Melissa McDole





 Ischial tuberosity
 Sacrotuberous ligament
 Tip of the coccyx
Pelvic inlet divides pelvis into greater (false) pelvis and lesser (true) pelvis
Greater pelvis is superior to the pelvic brim and is bounded bilaterally by the ala of the ilium
Lesser pelvis is inferior to the pelvic brim
Inferior border of lesser pelvis is pelvic diaphragm
Erect posture
o Anterior superior iliac spines and anterior aspect of pubis are in same vertical plane
o N352
ANAL TRIANGLE





Perineum
o Diamond-shaped area between the this; divided into 2 triangles
 Anal triangle—posterior part of perineum and contains anal canal and anus
 Urogenital triangle—anterior part of perineum and contains urethra and external genitalia
The pelvic diaphragm separates the pelvic cavity from the perineum
Gluteus maximus muscle
Inferior cuneal nerves
Sacrotuberous ligament
o Gluteus maximus m. attaches to the sacrotuberous ligament and the sacrum
Ischioanal fossa

Ischioanal (ischiorectal) fossa
o Wedged shaped area on either side of the anus
o Filled with fat and helps accommodate fetus during childbirth or distended anal canal during passage of feces
o Know nerves and vessels that pass through fossa—N411
 Inferior rectal (anal) nerve and vessels
o External and sphincter muscle—has 3 parts
 Subcutaneous—around anus
 Superficial—anchors anus to the perineal body and coccyx
36
Clinical Anatomy Grant’s Dissector Notes (Summer 2009 and Summer 2010)
Melissa McDole
o
o
o
o
o
 Deep—circular band that is fused with the pelvic diaphragm
Inferior surface of pelvic diaphragm—medial boundary of ischioanal fossa
Fascia of obturator internus m.—lateral boundary of ischioanal fossa
Inferior rectal nerve and vessels penetrate fascia of obturator internus m.
Inferior rectal vessels exit the pudendal canal to enter the ischioanal fossa
Pudendal canal contains:
 Pudendal nerve
 Internal pudendal artery and vein
MALE EXTERNAL GENITALIA AND PERINEUM


Scrotum: outpouching of the anterior abdominal wall
o superficial fascia of scrotum has no fat
o superficial fascia = dartos fascia—contains smooth muscle fibers (dartos muscle)
o scrotal ligament: band of tissue that anchors the inferior pole of the testes to scrotum
 remnant of gubernaculum testis –N387
scrotal septum: divides the scrotum into 2 compartment
Spermatic cord—N387




spermatic cord contains:
o ductus deferens,
o testicular vessels
o lymphatics
o nerves
contents of spermatic cord are surrounded by 3 fascial layers—coverings of spermatic cord—derived from layers of anterior abdominal
wall—coverings are added to cord as the cord passes through the inguinal canal
ductus deferens (vas deferens)
o within spermatic cord
o hard and cord-like
coverings of spermatic cord
o external spermatic fascia—from external oblique muscle
o cremasteric muscle and fascia—from internal oblique muscle
o internal spermatic fascia—from transversalis fascia
37
Clinical Anatomy Grant’s Dissector Notes (Summer 2009 and Summer 2010)
Melissa McDole





pampiniform plexus of veins
artery of the ductus deferens
o small vessel located on surface of ductus deferens
ductus deferens passes through deep inguinal ring lateral to the inferior epigastric vessels
testicular artery
the sensory nerve fibers, autonomic nerve fibers, and lymphatic vessels accompany the blood vessels in spermatic cord
**Clinical correlation**
Vasectomy
 ductus deferens can be surgically interrupted in the superior part of the scrotum (vasectomy)
 sperm production continues but spermatozoa cannot reach urethra
Testis—N390






tunical vaginalis
o serous sac from parietal peritoneum that covers the testis
o has a visceral and parietal layer
o cavity of the tunica vaginalis—only potential space that has small amount of serious fluid
ductus deferens joins epididymis inferiorly
epididymis
o tail, body and head
tunica albuginea—fibrous capsule of testis
septa—divides interior testis into lobules
seminiferous tubules
**Clinical correlation
Lymphatic drainage of testis
 lymphatics from scrotum drain to the superficial inguinal lymph nodes
 inflammation of scrotum may cause tender, enlarged superficial inguinal lymph nodes
 lymphatics from testis follow the testicular vessels through the inguinal canal and into the abdominal cavity where they drain into lumbar
(lateral aortic) nodes and preaortic nodes
 testicular tumors may metastasize to lumbar and preaortic lymph nodes, not to superficial inguinal lymph nodes
38
Clinical Anatomy Grant’s Dissector Notes (Summer 2009 and Summer 2010)
Melissa McDole
MALE UROGENITAL TRIANGLE

posterior scrotal nerve and vessels
o enter urogenital triangle by passing lateral to the external anal sphincter muscle
o posterior scrotal nerve and vessels supply the posterior part of the scrotum
Superficial perineal pouch—N381



the superficial perineal fascia has a superficial fatty layer and a deep membranous layer
the superficial fatty layer is continuous with the superficial fatty layer of the lower abdominal wall, ischioanal fossa, and thigh
membranous layer of the superficial perineal fascia (Colles’ fascia)
o continuous with the membranous layer of superficial facia of the anterior abdominal wall (Scarpa’s fascia) and the dartos fascia
of the penis and the scrotum
o membranous layer of superficial perineal fascia is attached to the ischiopubic ramus as far posteriorly as the ischial tuberosity and
to the posterior edge of the perineal membrane
o membranous layer of superficial perineal fascia forms the superficial boundary of the superficial perineal pouch (space)
**Clinical correlation**
Superficial perineal pouch
 if urethra is injured in perineum, urine may escape into superficial perineal pouch
 urine may spread into scrotum and penis, then upward into lower abdominal wall between membranous layer of abdominal superficial
fascia (Scarpa’s fascia) and aponeurosis of external oblique muscle
 urine doesn’t enter the thigh because the membranous layer of the superficial fascia attaches to the fascia lata, ischiopubic ramus, and
posterior edge of the perineal membrane


contents of the superficial perineal pouch in the male
o three paired muscles (superficial transverse perineal, bulbospongiosus, and ischiocavernosus)
o crura of the penis
o bulb of the penis
o arteries, veins, and nerves that supply these structures
bulbospongiosus muscle—in midline of urogenital triangle
o covers superficial surface of the bulb of the penis
o posterior attachment: bulbospongiosus muscle of the opposite side (in midline raphe) and perineal body
o anterior attachment: corpus cavernosum penis
39
Clinical Anatomy Grant’s Dissector Notes (Summer 2009 and Summer 2010)
Melissa McDole




o function: compresses the bulb of the penis to expel urine or semen
Ischiocavernosus m.
o Lateral to bulbospongiosus m.
o covers superficial surface of crus of penis
o proximal attachment: ischial tuberosity and ischiopubic ramus
o distal attachment: crus of the penis
o function: forces blood from the crus of the penis into the distal part of the corpus cavernosum penis
Superficial transverse perineal m.
o lateral attachment: ischial tuberosity and ischiopubic ramus
o medial attachment: perineal body
 perineal body—fibromuscular mass located anterior to the anal canal and posterior to the perineal membrane that serves
as an attachment for several muscles
o function: helps support the perineal body
o perineal membrane
 deep boundary of the superficial perineal pouch and the bulb of the penis and crura are attached to it
bulb of the penis
o continuous with the corpus spongiosum penis
o contains portion of spongy urethra
crus of the penis
o proximal part of the corpus cavernosum penis
Penis—N381, 382


dorsal surface of the penis
o surface of penis closest to abdominal wall
penis
o superficial fascia of the penis (dartos fascia)—has no fat and contains the superficial dorsal vein of the penis
o deep fascia of the penis (Buck’s fascia)—investing fascia
o within deep fascia of the penis are:
 corpus spongiosum
 corpus cavernosum (paired)
 deep dorsal vein of the penis (unpaired)
 dorsal artery of the penis (paired)
 dorsal nerve of the penis (paired)
40
Clinical Anatomy Grant’s Dissector Notes (Summer 2009 and Summer 2010)
Melissa McDole
o




parts of the penis
 root (bulb and crura)
 body (shaft)
 glans penis
 corona of the glans
 prepuce
 frenulum
 external urethral orifice
o superficial dorsal vein
 drains into superficial external pudendal vein of inguinal region
o deep fascia of the penis
 deep dorsal vein of the penis—single vein in the midline most of the blood from the penis drains through the deep dorsal
vein in the prostatic venous plexus
 dorsal artery of the penis (2)—one artery on each side of the dorsal vein; dorsal artery of the penis is a terminal branch
of the internal pudendal artery
 dorsal nerve of the penis (2)—one nerve on each side of the midline, lateral to the deep dorsal artery; branch of pudendal
nerve
**know course of pudendal nerve and internal pudendal artery
Dorsal artery and nerve of the penis course deep to the perineal membrane before they emerge onto the dorsum of the penis
Deep dorsal vein passes between inferior pubic ligament and the anterior edge of the perineal membrane to enter the pelvis
Deep dorsal vein doesn’t accompany deep dorsal artery and nerve proximal to body of penis—N403, 410
Spongy Urethra—N385





Male urethra has 3 parts
o Prostatic urethra
o Membranous urethra
o Spongy urethra
 Portion located within corpus spongiosum penis
External urethral orifice—at tip of glans penis
Glans penis—distal expansion of corpus spongiosum
o Caps the two corpora cavernosa penis
Spongy urethra terminates by passing through the glans
Interior spongy urethra
41
Clinical Anatomy Grant’s Dissector Notes (Summer 2009 and Summer 2010)
Melissa McDole




o Navicular fossa—widening of the urethra in glans penis
Bulbourethral glands
Corpus cavernosum penis
Corpus spongiosum penis—N381
o Tunica albuginea of corpora cavernosa penis
o Tunica albuginea of the corpus spongiosum penis
o Septum penis
Deep artery of the penis
Deep perineal pouch








Contents of the deep perineal pouch in the male
o Membranous urethra
o External urethral sphincter muscle
o Bulbourethral gland
o Branches of internal pudendal vessels
o Branches of pudenda nerve
N383
Membranous urethra—extends from perineal membrane to prostate gland
o Shortest, thinnest, and narrowest, least distensible part of urethra
External urethral sphincter (sphincter urethrae) muscle
o Voluntary muscle that surrounds membranous urethra
o When external urethral sphincter muscle contracts, it compresses the membranous urethra and stops flow of urine
Deep transverse perineal muscle
o Lateral attachment: ischial tuberosity and ischiopubic ramus
o Medial attachment: perineal body
o Fiber direction and function are same as superficial transverse perineal muscle (contained in superficial perineal pouch)
Bulbourethral glands
o Located in deep perineal pouch
o Duct of gland passes through perineal membrane and drains into the proximal portion of the spongy urethra
Pudendal nerve
Internal pudendal artery
o Deep perineal pouch contains branches of the pudendal nerve and internal pudendal artery
42
Clinical Anatomy Grant’s Dissector Notes (Summer 2009 and Summer 2010)
Melissa McDole

o Nerve and artery supply external urethral sphincter muscle, deep transverse perineal muscle and penis
urogenital diaphragm
o includes the muscles in deep perineal pouch and perineal membrane
FEMALE UROGENITAL TRIANGLE
External Genitalia
N377
 vulva
o female external genitalia
o structures
 mons pubis
 anterior labial commissure
 labium majus
 clitoris
 prepuce
 glans
 frenulum of clitoris
 labium minus
 vestibule of the vagina—area between the labia minora
 external urethral orifice
 vaginal orifice
 opening of the paraurethral ducts—on each side of external urethra orifice
 frenulum of labia minora
 posterior labial commissure
 posterior labial nerve and vessels
o enter triangle by passing lateral to the external anal sphincter muscle
43
Clinical Anatomy Grant’s Dissector Notes (Summer 2009 and Summer 2010)
Melissa McDole
o
supply the posterior part of the labium majus
Superficial perineal pouch and clitoris—N378, 379







superficial perineal fascia has a superficial fatty layer and a deep membranous layer
in female—fatty layer provides shape of the labium majus and is continuous with the fat of the lower abdominal wall, ischioanal fossa,
and thigh
membranous layer of the superficial perineal fascia (Colles’ fascia)
o attached to the ischiopubic ramus as far posteriorly as the ischial tuberosity, and to the posterior edge of the perineal membrane
o forms superficial boundary of the superficial perineal pouch (space)
contents of the superficial perineal pouch in the female
o three muscles (ischiocavernosus, bulbospongiosus, and superficial transverse perineal)
o crus of the clitoris
o bulb of the vestibule
o greater vestibular gland
 structures are paired
 superficial perineal pouch also contains blood vessels and nerves for these structures
bulbospongiosus muscle
o lateral to the labium minus
o covers the superficial surface of the bulb of the vestibule
o posterior attachment: perineal body
o anterior attachment: corpus cavernosum clitoris
o in female—does not join the bulbospongiosus muscle of the opposite side across the midline (it does in the male)
Ischiocavernosus m.
o Lateral to bulbospongiosus m.
o covers superficial surface of the crus of the clitoris
o proximal attachment: ischial tuberosity and ischiopubic ramus
o distal attachment: crus of the clitoris
o function: forces blood from crus of clitoris into distal part of the corpus cavernosum clitoris
superficial transverse perineal muscle
o at posterior border of urogenital triangle
o lateral attachment: ischial tuberosity and ischiopubic ramus
o medial attachment: perineal body—fibromuscular mass between the anal canal and the posterior edge of the perineal
membrane—attachment for several muscles
44
Clinical Anatomy Grant’s Dissector Notes (Summer 2009 and Summer 2010)
Melissa McDole
o helps support perineal body
perineal membrane
o deep boundary of the superficial perineal pouch
o bulb of vestibule and crura are attached to it
 bulb of the vestibule
o elongated mass of erectile tissue that is lateral to the vaginal orifice
 greater vestibular gland
o found in superficial perineal pouch immediately posterior to the bulb of the vestibule
 commissure of bulbs
o continuous with the glans of the clitoris
 crus of the clitoris
o proximal part of corpus cavernosum clitoris
 two copra cavernosa form the body of the clitoris—N379
Deep Perineal Pouch








is superior (deep) to the perineal membrane
contents of perineal pouch in the female
o urethra
o portion of vagina
o external urethral sphincter muscle
o branches of the internal pudendal vessels
o branches of the pudendal nerve
N379
Urethra
o Extends from internal urethral orifice in the urinary bladder to the external urethral orifice in the vestibule of the vagina
External urethral sphincter (sphincter urethrae) muscle
o Voluntary muscle that surrounds urethra
o When it contracts, it compresses the urethra ans stops flow of urine
Deep transverse perineal muscle
o Lateral attachment: ischial tuberosity and ischiopubic ramus
o Medial attachment: perineal body
o Fiber direction and function is same as those of the superficial transverse perineal muscle (content in superficial perineal pouch)
Other contents of deep perineal pouch include:
45
Clinical Anatomy Grant’s Dissector Notes (Summer 2009 and Summer 2010)
Melissa McDole
o
o

Branches of the internal pudendal artery
Branches of the pudendal nerve
 Supply the external urethral sphincter muscle, deep transverse perineal muscle, and clitoris
Urogenital diaphragm
o Muscles within the deep perineal pouch plus the perineal membrane
**Clinical Correlation
Obstetric Considerations
 As head of baby passes through vagina during childbirth, the anus and levator ani muscle are forced posteriorly toward sacrum and coccyx
 Urethra is forced anteriorly toward pubic symphysis
 Perineal lacerations during childbirth are common and it may be needed to surgically widen the vaginal orifice (episiotomy)
 If perineal body is lacerated, it must be repaired to prevent weakness of pelvic floor,-- results in prolapse of urinary bladder, uterus, or
rectum
 To ease pain during childbirth a pudendal nerve block is done by injecting local anesthesia around pudendal nerve near ischial spine
 Injection is done by first palpating ischial spine through the vagina, and the needle is directed toward the ischial spine
FEMALE PELVIC CAVITY—p. 137 - 147

Female pelvic cavity contains the following:
o Urinary bladder anteriorly
o Female internal genitalia
o Rectum posterior
o Adnexa: includes ovaries, uterine tubes, and ligaments of the uterus
Peritoneum—N360

Peritoneum
o Passes from anterior abdominal wall superior to the pubis
o Covers the superior surface of the urinary bladder
o Passes from superior surface of the urinary bladder to the uterus where it forms the vesicouterine pouch
o Covers the fundus and body of the uterus and contacts wall of the posterior part of the vaginal fornix
o Forms the rectouterine pouch between the uterus and rectum
o Covers the anterior surface and sides of the rectum
o Forms the sigmoid mesocolon beginning at the level S3
46
Clinical Anatomy Grant’s Dissector Notes (Summer 2009 and Summer 2010)
Melissa McDole


Paravesical fossa
o On side of urinary bladder
Pararectal fossa
o Posteriorly
o On each side of rectum
**Clinical Correlation**
Pelvic Peritoneum


When urinary bladder fills, peritoneum on anterior abdominal wall elevated above level of pubis
A filled bladder can be approached with a needle superior to the pubis without entering the peritoneal cavity

Broad ligament of the uterus
o
o



Formed by 2 layers of the peritoneum that extend from the lateral side of the uterus to the lateral pelvic wall
Uterine tube
 Contained within superior margin of broad ligament
o Broad ligament has 3 parts—N370
 Mesosalpinx(1)—supports the uterine tube
 Mesovarium(2)—attaches ovary to the posterior aspect of the broad ligament
 Mesometrium(3)—part of broad ligament that is below the attachment of the mesovarium
 Tissue enclosed between 2 layers o the broad ligament is the parametrium
Round ligament of the uterus
o Can see through anterior layer of the broad ligament
o Passes over the pelvic brim and exists abdominal cavity by passing through the deep inguinal ring, lateral to the inferior epigastric
vessels
o Passes through inguinal canal and ends in labium majus
Ovarian ligament
o Fibrous cord within broad ligament—
o Connects ovary to uterus
Suspensory ligament of the ovary
o A peritoneal fold that covers the ovarian vessels
o Extends into the greater pelvis from the superior aspect of the ovary
47
Clinical Anatomy Grant’s Dissector Notes (Summer 2009 and Summer 2010)
Melissa McDole



Endopelvic fascia (extraperitoneal fascia)
o Has condensations of connective tissue that passively support the uterus—N364
 Uterosacral (sacrogenital) ligament
 Extends from cervix to the sacrum
 Underlies the uterosacral fold
 Transverse cervical ligament (cardinal ligament)
 Extends from cervix to the lateral wall of the pelvis
 Pubocervical (pubovesical) ligament
 Extends from the pubis to the cervix
Public symphysis
Sacrum
Female internal genitalia—N360, 365




External urethral orifice
External urethral sphincter muscle
o Surrounds urethra
Vagina
o Vaginal fornix has 4 parts:
 Anterior
 Lateral (2)
 Posterior
o Anterior vaginal wall is shorter than the posterior vaginal wall
o Posterior wall of the vagina contacts the peritoneum that lines the rectouterine pouch
Uterus
o Tilted approximately 90 degrees anterior to axis of vagina
o Position of uterus changes as bladder fills and during pregnancy—N371
o Features of uterus
 Fundus—
 Rounded part of body that lies superior to the attachments of the uterine tubes
 Body
 Part of uterus between the fundus and cervix
 Vesical surface of body of uterus faces vesicouterine pouch
48
Clinical Anatomy Grant’s Dissector Notes (Summer 2009 and Summer 2010)
Melissa McDole











 Intestinal surface faces the rectouterine pouch
 Broad ligament is attached to the lateral surface of the body of the uterus
Isthmus
 Narrowed portion of the body that is superior to the cervix
Cervix
 Thick-walled portion of uterus that protrudes into vaginal canal
Uterine cavity
Endometrium—uterine mucosa
Myometrium—thick muscular wall of the uterus
Perimetrium (around)—peritoneal covering on surface of the uterus
Parametrium (beyond)—tissues within broad ligament
Uterine tube
o Passes laterally within the mesosalpinx
o Contains
 Isthmus—
 Narrow, medial one-third of uterine tube
 Ampulla
 Widest and longest part of the uterine tube
 Infundibulum
 Funnel-like end of the uterine tube
 Fimbriae
 Multiple processes that surround the distal margin of the infundibulum
Ovary
o Tubal (distal) extremity
o Uterine (proximal) extremity
o Ovarian vessels enter tubal extremity of ovary—ligament of the ovary is attached to the uterine extremity** objective
Ovarian fossa
o Shallow depression in lateral pelvic wall bounded by the ureter, external iliac vein, and uterine tube
Suspensory ligament of the ovary
o Ovarian vessels pass through this region**
URINARY BLADDER, RECTUM, AND ANAL CANAL--Female
49
Clinical Anatomy Grant’s Dissector Notes (Summer 2009 and Summer 2010)
Melissa McDole






Urinary bladder is a retroperitoneal organ surrounded by endopelvic fascia
Retropubic space (prevesical space): potential space between pubic symphysis and urinary bladder
Retropubic space is filled with fat and loose connective tissue that accommodates expansion of urinary bladder
Pubovesical ligament
o Condensation of fascia that ties neck of urinary bladder to pubis across the retropubic space
o Defines inferior limit of retropubic space
Lower 1/3 of rectum is surrounded by the endopelvic fascia
Middle and upper thirds of rectum are partially covered by peritoneum
Urinary bladder—N366




Parts of the urinary bladder
o Apex
 Pointed part directed toward anterior abdominal wall
 Identified by attachment of urachus
o Body
 Between apex and fundus
o Fundus
 Inferior part of posterior wall
 Called base of the bladder
 In female the fundus is related to the vagina and cervix
o Neck
 Where urethra exits urinary bladder
 Wall thickens to form the internal urethral sphincter—is involuntary muscle
4 surfaces of urinary bladder
o Superior—covered by peritoneum
o Posterior—covered by perineum on superior part and by endopelvic fascia on its inferior part
o Inferolateral (2)—covered by endopelvic fascia
Wall of urinary bladder
o Consists of bundles of smooth muscle called detrusor muscle
Trigone—inner surface of the fundus
o Angles of the trigone are
 Internal urethral orifice—located at most inferior point in urinary bladder –N366
50
Clinical Anatomy Grant’s Dissector Notes (Summer 2009 and Summer 2010)
Melissa McDole
 2 orifices of the ureters
Mucous membrane over trigone is smooth
Mucous membrane lining the other parts of the urinary bladder lies in folds when the bladder is empty but accommodates
expansion
When bladder is full, pressure of urine flattens the part of the ureter within the wall of the bladder and prevents reflux of urine into the
ureter
o
o

**Clinical Correlation
Kidney Stones
 Kidney stones pass through ureter to urinary bladder and may become lodged in ureter
 Point where ureter passes through wall of bladder is a narrow passage
 If kidney stone becomes lodged, severe colicky pain results
 Pain stops suddenly once the stone passes into the bladder

The ureter crosses inferiorly to the uterine artery and superior to the vaginal artery—N400
Rectum and Anal Canal—N360, 393




Rectum begins at level S3
Rectum follows curvature of sacrum
Ampulla of rectum
o At ampulla, rectum bends approximately 80 degrees posteriorly (anorectal flexure) and is continuous with anal canal
o Inner surface of rectum is smooth except for areas of transverse rectal folds
 Usually one transverse rectal fold on the right and 2 on the left
Anal canal
o Passes out of pelvic cavity and enters anal triangle of perineum
o Features include
 Anal columns
 5 to 10 longitudinal ridges of mucosa in proximal anal canal
 Contain branches of superior rectal artery and vein
 Anal valves
 Semilunar folds of mucosa that unite distal ends of anal columns
 External to each valve is a small pocket called an anal sinus
51
Clinical Anatomy Grant’s Dissector Notes (Summer 2009 and Summer 2010)
Melissa McDole

Pectinate line—
 Irregular line formed by all of the anal valves
**Clinical Correlation
Hemorrhoids
 In anal columns, superior rectal veins of hepatic portal system anastomose with middle and inferior rectal veins of IVC (systemic)
 Abnormal increase of blood pressure in hepatic portal system causes engorgement of veins in anal columns resulting in internal
hemorrhoids
 Internal hemorrhoids are covered by mucous membrane and insensitive to pain because mucous membrane is innervated by autonomic
nerves
 External hemorrhoids
o Enlargements of tributaries of inferior rectal veins
o Covered by skin and very sensitive to painful stimuli because they are innervated by somatic nerves (inferior rectal nerves)

Anal sphincter muscles
o External anal sphincter muscle
o Internal anal sphincter muscle
INTERNAL ILIAC ARTERY AND SACRAL PLEXUS--Female




Common iliac artery divides to form external and internal iliac arteries
External iliac artery distributes to lower limb
Internal iliac artery distributes to the pelvis
internal iliac artery has most variable branching pattern
o divides into an anterior and posterior division
 anterior division includes:
 mainly visceral (branches to the urinary bladder, internal genitalia, external genitalia, rectum, and gluteal region)
 posterior division includes:
 parietal (branches to the pelvic walls and gluteal region)
Blood Vessels—N400, 402

common iliac artery
52
Clinical Anatomy Grant’s Dissector Notes (Summer 2009 and Summer 2010)
Melissa McDole

internal iliac artery
o anterior division of internal iliac artery
o umbilical artery
 in medial umbilical fold—medial umbilical ligament (obliterated portion of the umbilical artery)—can trace it
posteriorly to the umbilical artery
 superior vesical arteries
 from the inferior surface of the umbilical artery and descend to the superolateral aspect of the urinary bladder
o obturator artery
 passes through obturator canal in lateral wall of the pelvis
 aberrant obturator artery
o uterine artery
 courses along inferior attachment of broad ligament
 passes superior to the ureter
 divides into a large superior branch to the body and fundus of the uterus and a smaller branch to the cervix and vagina
**clinical correlation**
Uterine artery
o of clinical importance that the close proximity of ureter and the uterine artery near the lateral fornix of the vagina
o during hysterectomy, the uterine artery is tied off, and cut
o the ureter may be clamped, tied off and cut accidentally—where it crosses the uterine artery
o results in consequences to the kidney
o mnemonic
o “water under the bridge”
o Water = urine; bridge = uterine artery
o
o
o
Vaginal artery
 Passes floor of pelvis inferior to the ureter
 Supplies vagina and urinary bladder
 Ureter passes between vaginal artery and the uterine artery
Middle rectal artery
 Courses medially toward rectum
Internal pudendal artery
 Exits pelvic cavity by passing through greater sciatic foramen inferior to the piriformis muscle
 Often comes from common trunk with the inferior gluteal artery
53
Clinical Anatomy Grant’s Dissector Notes (Summer 2009 and Summer 2010)
Melissa McDole
o





Inferior gluteal artery
 Usually passes out of pelvic cavity between ventral rami S2 and S3
 Exits pelvis by passing through the greater sciatic foramen inferior to the piriformis muscle
 May share a common trunk with the internal pudendal artery, or less commonly with the superior gluteal artery
Branches of posterior division of internal iliac artery
o Iliolumbar artery
 Passes posteriorly, then ascends between lumbosacral trunk and obturator nerve
 May arise from common trunk with lateral sacral artery
o Lateral sacral artery
 Branches into a superior and an inferior branch
 Inferior branch passes anterior to the sacral ventral rami
o Superior gluteal artery
 Exits pelvic cavity by passing between the lumbosacral trunk and ventral ramus of spinal nerve S1
Vesicle venous plexus
Uterine venous plexus
Vaginal venous plexus
Rectal venous plexus
o **** All of these plexuses drain into the internal iliac vein
Nerves—N412, 499





Sacral plexus
Coccygeal plexus
o **both plexuses are located between the pelvic viscera and lateral pelvic wall within endopelvic fascia
Somatic nerve plexuses are formed by contributions by ventral rami of spinal nerves L4 to S4
Primary visceral nerve plexus of pelvic cavity is the inferior hypogastric plexus
o Formed by contributions from hypogastric nerves, sympathetic trunks, and pelvic splanchnic nerves
Sacral plexus of nerves
o Related to anterior surface of piriformis muscle
o Lumbosacral trunk
 Ventral rami of L4 and l5
 Joins sacral plexus
o Ventral rami of S2 and S3 come between proximal attachments of piriformis muscle
54
Clinical Anatomy Grant’s Dissector Notes (Summer 2009 and Summer 2010)
Melissa McDole
o


Sciatic nerve
 Formed by ventral rami of spinal nerves L4 – S3
 Exits pelvis by passing through greater sciatic foramen—inferior to the piriformis muscle
o Superior gluteal artery
 Passes between lumbosacral trunk and the ventral ramus of spinal nerves S1and exits pelvis by passing superior to
piriformis muscle
o Inferior gluteal artery
 Passes between ventral rami of spinal nerves S2 and S3
 Exits pelvis by passing inferior to piriformis muscle
o Pudendal nerve
 Receives nerves from ventral rami of spinal nerves S2, S3, and S4
 Exits pelvis by passing inferior to piriformis muscle
Pelvic splanchnic nerves (nervi erigentes)
o Branches of ventral rami of spinal nerves S2 – S4
o Carry preganglionic parasympathetic axons
o Innervate pelvic organs and distal GI tract (from left colic flexure through the anal canal)—N412
Sacral portion of the sympathetic trunk
o Is on anterior surface of sacrum, medial to ventral sacral foramina
 Sympathetic trunk
 Continues from abdominal region into pelvis
 Sympathetic trunks of the two sides join in the midline near the level of coccyx to form the ganglion impar
 Gray rami communicantes
 Connect sympathetic ganglia to the sacral ventral rami
 Each one carries postganglionic sympathetic fibers to a ventral ramus for distribution to the lower extremity and
perineum
 Sacral splanchnic nerves
 Arise from 2 or 3 sacral sympathetic ganglia and pass directly to the inferior hypogastric plexus
 Carry sympathetic fibers that distribute to the pelvic viscera
**Clinical correlation
Pelvic nerve plexuses
 Pelvic splanchnic nerves (parasympathetic outflow—S2-S4) are related to lateral aspects of the rectum
 Inferior hypogastric plexus is located in connective tissue lateral to the uterus
o Autonomic nerve plexuses can be injured during surgery, causing loss of bladder control
55
Clinical Anatomy Grant’s Dissector Notes (Summer 2009 and Summer 2010)
Melissa McDole
PELVIC DIAPHRAGM--Female






Pelvic diaphragm
o Muscular floor of pelvic cavity
o Formed by levator ani muscle and coccygeus muscle and fasciae covering superior and inferior surfaces
o Extends from pubic symphysis to the coccyx
o Laterally, it is attached to the fascia covering the obturator internus muscle
o The urethra and vagina and anal canal pass through midline openings in pelvic diaphragm called the urogenital hiatus and anal
hiatus, respectively
N356
Tendinous arch of the levator ani muscle
o Lies inferior to the line connecting medial surface of ischial spine and obturator canal
o Superior edge of pelvic diaphragm
3 muscles of levator ani
o Puborectalis muscle
 Proximal attachment: body of pubis
 Distal attachment: puborectalis muscle of the opposite side (in midline raphe)
 Forms lateral boundary of urogenital hiatus
 The two puborectalis muscles form a “puborectal sling” which causes the anorectal flexure at the ampulla of the rectum
 Puborectalis muscles relax and anorectal flexure straightens during defecation
o Pubococcygeus muscle
 Proximal attachment: body of pubis
 Distal attachment: coccyx and anococcygeal raphe
o Ileococcygeus muscle
 Proximal attachment: tendinous arch
 Distal attachment: coccyx and anococcygeal raphe
o Levator ani muscle supports pelvic viscera and resists increase in intra-abdominal pressure
Coccygeus muscle
o Forms posterior border of pelvic diaphragm
o Proximal attachment: ischial spine
o Distal attachment: lateral border of the coccyx and lowest part of sacrum
Obturator internus muscle
o Forms lateral wall of ischioanal fossa
56
Clinical Anatomy Grant’s Dissector Notes (Summer 2009 and Summer 2010)
Melissa McDole

o Proximal attachment: margin of obturator foramen and inner surface of the obturator membrane
o Forms lateral wall of pelvic cavity, superior to tendinous arch of the levator ani
o Forms lateral wall of perineum, inferior to the tendinous arch
Lymphatic drainage of the pelvis—N406
o Internal iliac nodes
o External iliac nodes
o Common iliac nodes
o Sacral nodes
o Lumbar nodes
p. 133
**Clinical correlation**
Lymphatic drainage of labium majus
 Lymphatics from labium majus drain to superficial inguinal lymph nodes
 Inflammation of labium majus may cause tender, enlarged superficial inguinal lymph nodes
MALE PELVIC CAVITY –PP. 124 – 133

Male pelvic cavity contains urinary bladder (anteriorly), male internal genitalia, and rectum (posteriorly)
Peritoneum—N361


Peritoneum:
o Passes from anterior abdominal wall superior to pubis
o Covers superior surface of urinary bladder
o Passes inferiorly along posterior surface of the urinary bladder
o Has close relationship to the superior ends of the seminal vesicles
o Passes inferiorly between the urinary bladder and rectum to form rectovesical pouch
o Contacts anterior surface and sides of rectum
o Forms sigmoid mesocolon at level S3
Paravesical fossa
o Laterally on each side of urinary bladder
o Posteriorly, pararectal fossa is on each side of rectum
**Clinical Correlation**
57
Clinical Anatomy Grant’s Dissector Notes (Summer 2009 and Summer 2010)
Melissa McDole
Pelvic Peritoneum


As urinary bladder fills, peritoneal reflection is elevated above level of pubis and is raised from anterior abdominal wall
A filled urinary bladder can be approached with a needle superior to the pubis without entering peritoneal cavity
Male internal genitalia—N361











Perineal membrane
o Located deep to the bulb of the penis
o Thin line at deep edge of bulb
External urethral sphincter muscle
o Superior (deep) to perineal membrane
o Surrounds membranous urethra
Three parts of urethra
o Prostatic urethra
o Membranous urethra
o Spongy urethra
Inferior of the prostatic urethra—N385
o On posterior wall:
 Urethral crest—longitudinal ridge
 Seminal colliculus—enlargement of urethral crest
 Prostatic sinus—groove on either side of seminal colliculus
 Prostatic utricle—small opening on midline of seminal colliculus
 Opening of ejaculatory duct—one on each side of prostatic utricle
Ductus deferens enters deep inguinal ring lateral to the inferior epigastric vessels
The ductus deferens passes superior and then medial to the branches of the internal iliac artery
Ductus deferens crosses superior to the ureter—N363
Rectovesical septum
o Endopelvic fascia between the rectum and urinary bladder
Ductus deferens contacts fundus (posterior surface) of urinary bladder
Ampulla of ductus deferens
o Enlarged portion before its end—N384
Seminal vesicle
58
Clinical Anatomy Grant’s Dissector Notes (Summer 2009 and Summer 2010)
Melissa McDole
o
o

Lateral to the ampulla of the ductus deferens in rectovesical septum
Close to prostate, duct of seminal vesicle joins ductus deferens to form ejaculatory duct
 Ejaculatory duct empties into the prostatic urethra on the seminal colliculus
Prostate
o Apex—pointed inferiorly
o Base—superior against neck of urinary bladder
o Lobes of prostate
URINARY BLADDER, RECTUM, AND ANAL CANAL--Male






Urinary bladder hold urine; when empty, it is located within pelvic cavity; when filled it extends into abdominal cavity
Urinary bladder is a subperitoneal organ surrounded by endopelvic fascia
Between pubic symphysis and urinary bladder there is a potential space called the retropubic space (prevesical space)
o Filled with fat and loose connective tissue
Puboprostatic ligament
o Condensation of fascia that ties the prostate to the inner surface of the pubis
o Inferior limit of retropubic space
Lower 1/3 of rectum is surrounded by endopelvic fascia
Middle and upper thirds of rectum are partially covered by peritoneum
Urinary bladder—N366



Parts of urinary bladder
o Apex—pointed part directed toward anterior abdominal wall; attachment of urachus
o Body—between apex and fundus
o Fundus—inferior part of posterior wall (base of urinary bladder)
 Fundus is related to the ductus deferens, seminal vesicles, and rectum
o Neck—where urethra exits urinary bladder
 Wall thickens to form the internal urethral sphincter—an involuntary muscle
Four surfaces of urinary bladder
o Superior—covered by peritoneum
o Posterior—covered by peritoneum on superior part and by endopelvic fascia of rectovesical septum on inferior part
o Inferolateral (2)—covered by endopelvic fascia
Wall of bladder
59
Clinical Anatomy Grant’s Dissector Notes (Summer 2009 and Summer 2010)
Melissa McDole

o Has bundles of smooth muscle called the detrusor muscle
Trigone
o Inner surface of fundus
o Internal urethral orifice
 Located most inferior in urinary bladder—N366
o 2 orifices of the ureters
Rectum and anal canal—N361




Rectum begins at S3
Rectum follows curvature of the sacrum
Ampulla of the rectum
o Rectum bends approximately 80 degrees posteriorly (anorectal flexure) and is continuous with anal canal
Prostate and seminal vesicles are located close to anterior wall of rectum
**Clinical Correlation
Rectal Exam
 Digital rectal exam is part of physical exam
 Size and consistency of prostate gland can be assessed by palpation through anterior wall of rectum




Inner surface of rectum has smooth mucous membrane except for presence of transverse rectal folds (one on left and right)
Anal canal—passes out of pelvic cavity and enters anal triangle of perineum
o Anal columns—contain branches of superior rectal artery and vein
o Anal valves—semilunar folds of mucosa that unite distal ends of anal columns
 Anal sinus
o Pectinate line
External anal sphincter muscle
Internal anal sphincter muscle
INTERNAL ILIAC ARTERY AND SACRAL PLEXUS--Male


Common iliac artery divides to form external and internal iliac arteries
External iliac artery distributes to lower limb
60
Clinical Anatomy Grant’s Dissector Notes (Summer 2009 and Summer 2010)
Melissa McDole


Internal iliac artery distributes to the pelvis
internal iliac artery has most variable branching pattern
o divides into an anterior and posterior division
 anterior division includes:
 mainly visceral (branches to the urinary bladder, internal genitalia, external genitalia, rectum, and gluteal region)
 posterior division includes:
 parietal (branches to the pelvic walls and gluteal region)
Blood Vessels—N402, 403


common iliac artery
internal iliac artery
o anterior division of internal iliac artery
o umbilical artery
 in medial umbilical fold—medial umbilical ligament (obliterated portion of the umbilical artery)—can trace it
posteriorly to the umbilical artery
 superior vesical arteries
 from the inferior surface of the umbilical artery and descend to the superolateral aspect of the urinary bladder
o obturator artery
 passes through obturator canal in lateral wall of the pelvis
 aberrant obturator artery
o Middle rectal artery
 Courses medially toward rectum
 Comes from inferior vesical artery
 Sends branches to seminal vesicle and prostate
o Internal pudendal artery
 Exits pelvic cavity by passing through greater sciatic foramen inferior to the piriformis muscle
 Often comes from common trunk with the inferior gluteal artery
o Inferior gluteal artery
 Usually passes out of pelvic cavity between ventral rami S2 and S3
 Exits pelvis by passing through the greater sciatic foramen inferior to the piriformis muscle
 May share a common trunk with the internal pudendal artery, or less commonly with the superior gluteal artery

Branches of posterior division of internal iliac artery
61
Clinical Anatomy Grant’s Dissector Notes (Summer 2009 and Summer 2010)
Melissa McDole
o




Iliolumbar artery
 Passes posteriorly, then ascends between lumbosacral trunk and obturator nerve
 May arise from common trunk with lateral sacral artery
o Lateral sacral artery
 Branches into a superior and an inferior branch
 Inferior branch passes anterior to the sacral ventral rami
o Superior gluteal artery
 Exits pelvic cavity by passing between the lumbosacral trunk and ventral ramus of spinal nerve S1
Prostatic venous plexus
Vesical venous plexus
Rectal venous plexus
o **** All of these plexuses drain into the internal iliac vein
Deep dorsal vein of penis
o Inferior to pubic symphysis
o Empties into prostatic venous plexus
Nerves—N410, 499





Sacral plexus
Coccygeal plexus
o **both plexuses are located between the pelvic viscera and lateral pelvic wall within endopelvic fascia
Somatic nerve plexuses are formed by contributions by ventral rami of spinal nerves L4 to S4
Primary visceral nerve plexus of pelvic cavity is the inferior hypogastric plexus
o Formed by contributions from hypogastric nerves, sympathetic trunks, and pelvic splanchnic nerves
Sacral plexus of nerves
o Related to anterior surface of piriformis muscle
o Lumbosacral trunk
 Ventral rami of L4 and l5
 Joins sacral plexus
o Ventral rami of S2 and S3 come between proximal attachments of piriformis muscle
o Sciatic nerve
 Formed by ventral rami of spinal nerves L4 – S3
 Exits pelvis by passing through greater sciatic foramen—inferior to the piriformis muscle
o Superior gluteal artery
62
Clinical Anatomy Grant’s Dissector Notes (Summer 2009 and Summer 2010)
Melissa McDole



Passes between lumbosacral trunk and the ventral ramus of spinal nerves S1and exits pelvis by passing superior to
piriformis muscle
o Inferior gluteal artery
 Passes between ventral rami of spinal nerves S2 and S3
 Exits pelvis by passing inferior to piriformis muscle
o Pudendal nerve
 Receives nerves from ventral rami of spinal nerves S2, S3, and S4
 Exits pelvis by passing inferior to piriformis muscle
Pelvic splanchnic nerves (nervi erigentes)
o Branches of ventral rami of spinal nerves S2 – S4
o Carry preganglionic parasympathetic axons
o Innervate pelvic organs and distal GI tract (from left colic flexure through the anal canal)—N412
Sacral portion of the sympathetic trunk
o Is on anterior surface of sacrum, medial to ventral sacral foramina
 Sympathetic trunk
 Continues from abdominal region into pelvis
 Sympathetic trunks of the two sides join in the midline near the level of coccyx to form the ganglion impar
 Gray rami communicantes
 Connect sympathetic ganglia to the sacral ventral rami
 Each one carries postganglionic sympathetic fibers to a ventral ramus for distribution to the lower extremity and
perineum
 Sacral splanchnic nerves
 Arise from 2 or 3 sacral sympathetic ganglia and pass directly to the inferior hypogastric plexus
 Carry sympathetic fibers that distribute to the pelvic viscera
**Clinical correlation
Pelvic nerve plexuses
 Pelvic splanchnic nerves (parasympathetic outflow—S2-S4) are related to lateral aspects of the rectum
 Inferior hypogastric plexus is located in connective tissue lateral to the prostate
o Autonomic nerve plexuses can be injured during surgery, causing loss of bladder control and erectile dysfunction
PELVIC DIAPHRAGM--Male
63
Clinical Anatomy Grant’s Dissector Notes (Summer 2009 and Summer 2010)
Melissa McDole






Pelvic diaphragm
o Muscular floor of pelvic cavity
o Formed by levator ani muscle and coccygeus muscle and fasciae covering superior and inferior surfaces
o Extends from pubic symphysis to the coccyx
o Laterally, it is attached to the fascia covering the obturator internus muscle
o The urethra and anal canal pass through midline openings in pelvic diaphragm called the urogenital hiatus and anal hiatus,
respectively
N356- 358
Tendinous arch of the levator ani muscle
o Lies inferior to the line connecting medial surface of ischial spine and obturator canal
o Superior edge of pelvic diaphragm
3 muscles of levator ani
o Puborectalis muscle
 Proximal attachment: body of pubis
 Distal attachment: puborectalis muscle of the opposite side (in midline raphe)
 Forms lateral boundary of urogenital hiatus
 The two puborectalis muscles form a “puborectal sling” which causes the anorectal flexure at the ampulla of the rectum
 Puborectalis muscles relax and anorectal flexure straightens during defecation
o Pubococcygeus muscle
 Proximal attachment: body of pubis
 Distal attachment: coccyx and anococcygeal raphe
o Ileococcygeus muscle
 Proximal attachment: tendinous arch
 Distal attachment: coccyx and anococcygeal raphe
o Levator ani muscle supports pelvic viscera and resists increase in intra-abdominal pressure
Coccygeus muscle
o Forms posterior border of pelvic diaphragm
o Proximal attachment: ischial spine
o Distal attachment: lateral border of the coccyx and lowest part of sacrum
Obturator internus muscle
o Forms lateral wall of ischioanal fossa
o Proximal attachment: margin of obturator foramen and inner surface of the obturator membrane
o Forms lateral wall of pelvic cavity, superior to tendinous arch of the levator ani
o Forms lateral wall of perineum, inferior to the tendinous arch
64
Clinical Anatomy Grant’s Dissector Notes (Summer 2009 and Summer 2010)
Melissa McDole

Lymphatic drainage of the pelvis—N408
o Internal iliac nodes
o External iliac nodes
o Common iliac nodes
o Sacral nodes
o Lumbar nodes
65