ABDOMEN
Muscles of Abdominal Wall
- Transversalis fascia
 Deep fascia that lines the muscles of abdomen
- Linea alba
 Combined aponeurosis of 3 abdominal muscles:
o External abdominal oblique, internal abdominal oblique, transversus abdominus mm.
o Attachments at the xiphoid process of the sternum and the pelvic symphysis
- External abdominal oblique m.
- Internal abdominal oblique m.
 Cremaster m.
- Transversus abdominus m.
- Rectus abdominus m.
 Paired muscles that run longitudinally on either side of the linea alba
- Diaphragm
 Outer and inner components
o 3 muscular parts make up outer component
 Sternal (where diaphragm is attached to sternum)
 Costal (where diaphragm is attached to ribs)
 Lumbar
- Left and right muscular crura are attached to the lumbar vertebra (L3, L4)
- Right crus is larger and appears more cranially on radiographs
o Cupula (most cranial extend of diaphragm that buldges into thorax)
o Inner Central tendon
 Openings of diaphragm (3)
o Aortic hiatus (most dorsal)
 Located between the crura
 Transmits aorta, azygous v., and thoracic duct
o Esophageal hiatus
 Formed within the muscular right lumbar crus
 Transmits the esophagus, dorsal and ventral vagal trunks, esophageal vessels
 Most prone to herniation (hiatal hernia)
o Caval foramen
 Within the central tendon
 Transmits the caudal vena cava
Abdominal Viscera
- Peritoneum (continuous layer of serous epithelium lining abdominal cavity walls and viscera)
 Parietal peritoneum (lines abdominal wall
 Visceral peritoneum
o Where parietal peritoneum reflects to form mesenteries and cover organs
 Peritoneal cavity
o Potential space formed by the parietal and visceral layers of peritoneum
o NO organs within this cavity
- Greater omentum
 Remnant of dorsal mesogastrium
 Bi-layered (2 sheets) peritoneal sac that attaches the greater curvature of the stomach to the dorsal
body wall
o Superficial leaf
 Attaches to the greater curvature of the stomach
 Spleen is attached to the surface of this leaf
o Deep leaf
 Attaches to dorsal body wall
 Left lobe of the pancreas is enclosed in this leaf
Omental bursa
 Potential space between the superficial and deep sheets of the greater omentum
 Entrance to this bursa is the epiploic foramen, which is bounded:
- Dorsally – caudal vena cava
- Ventrally – portal v.
- Cranially – base of caudate process of caudate lobe of liver
- Caudally – hepatic a.
- Surgically important b/c this foramen can help locate the portal v., which
is necessary in surgeries to correct portosystemic shunts
Lesser omentum
 Remnant of ventral mesogastrium
 Single sheet of peritoneum that attaches the lesser curvature of the stomach to the liver
Liver
 Most cranial organ in the abdomen
 Parietal (diaphragmatic) surface (abuts the diaphragm)
 Visceral surface
o Contacts stomach (parietal surface) and right kidney
 6 lobes
o Left lateral lobe
 Gastric impression on visceral surface
o Left medial lobe
o Right medial lobe
 Contains fossa for gallbladder
 Variable fusion with quadrate lobe (especially in cat)
o Right lateral lobe
o Quadrate lobe
 Seen primarily between right and left medial lobes
 Forms part of fossa for gallbladder with rt. medial lobe
o Caudate lobe
 Papillary process
- Lies in lesser curvature of stomach and covered by lesser omentum
 Caudate process
- Deep renal fossa accommodates the right kidney
- Hepatorenal ligament b/w right kidney and renal fossa (variable)
 Falciform ligament
o Attached to parietal surface of liver b/w left and right medial lobes
o Attaches liver to the ventral abdominal midline just cranial to the umbilicus
o Contains round ligament of the liver
 Remnant of the umbilical v.
 Palpable cord in young animals
 Coronary ligament
o Attaches parietal surface of liver to diaphragm
o Continuous with the triangular ligaments and falciform ligament
 Triangular ligaments
o Lateral extensions of the coronary ligament
o Left triangular ligament (attaches left lateral lobe to diaphragm)
o Right triangular ligament (attaches right lateral lobe to diaphragm)
Spleen
 Largest lymphoid organs in the body
 Stores RBCs and iron, destroys worn RBCs, produces lymphocytes
 Attached to the superficial leaf of the greater omentum and lies left of midline
 Gastrosplenic ligament (attaches spleen to greater curvature of stomach)
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Vasculature
 Splenic a.
Stomach
 Lesser curvature
o Left gastric a.
o Right gastric a.
 Greater curvature
o Left gastroepiploic a.
o Right gastroepiploic a.
 4 parts
o Cardia (smallest part at esophageal entrance)
o Fundus (large, dome-shaped portion)
o Body (large, middle 1/3)
o Pylorus (distal 1/3)
 Pyloric antrum (thin-walled proximal portion)
 Pyloric canal
 Pyloric sphincter (pylorus)
 Gastric rugae
o Internal ridges formed by folding of the stomach wall
o Increase SA of stomach to allow for increased expansion and volume
Biliary passages
 Gallbladder
o Lies in fossa right medial and quadrate lobes of the liver
o Storage for liquid bile produced in the liver
 Hepatic ducts (carries bile from liver to gallbladder)
 Cystic duct (main duct from gallbladder)
 Bile duct
o Main duct formed from the union of cystic and hepatic ducts
o Enters wall of the descending duodenum and terminates on the major duodenal papilla
Duodenum (after pylorus of stomach)
 Cranial duodenal flexure
o Duodenum turns caudally to become descending duodenum (right of midline)
 Major duodenal papilla (cranial descending duodenum)
- Termination of bile duct and pancreatic duct
 Minor duodenal papilla (caudal descending duodenum)
- Termination of accessory pancreatic duct
 Caudal duodenal flexure
o Descending duodenum turns caudally to become ascending duodenum (left of midline)
o Caudal to the root of the mesentery
 Mesoduodenum
o Suspends descending duodenum
o Contains the right lobe of the pancreas
o Duodenocolic fold
 Attaches ascending duodenum to the mesocolon of descending colon
 Duodenojejunal flexure
o Where the duodenum joins the jejunum
 Vasculature
o Cranial pancreaticoduodenal a.
o Caudal pancreaticoduodenal a.
Jejunum (longest region of small bowel)
 Mesojejunum
o Supports jejunum and attaches the root of the mesentery to dorsal abdominal midline
 Vasculature
o Helps to distinguish jejunum from duodenum and ileum
Arcuate pattern
 Multiple jejunal aa. form extensive vascular arcades within mesojejunum
 Mesenteric lymph nodes
- Ileum (shortest region of small bowel)
 Ileocolic orifice
o Flow of ingesta passes from ileum to colon through this orifice
 Mesentery/mesocolon
o Suspends ileum
 Vasculature
o Parallel pattern
 Mesenteric ileal a. and antimesenteric ileal a. run parallel on either side of ileum
- Cecum
 Blind tube or diverticulum located at the junction of the ileum and colon
 Cecocolic orifice
o Communicating passageway b/w the ascending colon and cecum
- Colon
 Comprised of 3 continuous regions
o Ascending colon
 Travels cranially to the right of the midline
 Right colic flexure
- 90° turn to travel across abdominal midline as the transverse colon
 Supplied by right colic a. and middle colic a.
o Transverse colon
 Dorsal to the root of the mesentery
 Left colic flexure
- 90° turn to travel caudally as the descending colon
- Termination of vagus n.
 Supplied by right colic a. and middle colic a.
o Descending colon
 Supplied by the left colic a.
 Mesocolon
o Ascending (suspends ascending colon)
o Transverse (suspends transverse colon)
o Descending (suspends descending colon)
- Pancreas
 Produces secretions (primarily enzymes) that are carried to the duodenum to aid in digestion
 2 distinct lobes
o Left lobe
 Lies within deep sheet of the greater omentum
o Right lobe
 Lies within mesoduodenum adjacent to descending duodenum
o Body (lies at the pylorus)
 2 ducts
o Pancreatic duct
 Dominant in cat (occasionally absent in dog)
 Terminates on major duodenal papilla with bile duct
o Accessory pancreatic duct
 Dominant in the dog (only found in 20% of cats)
 Terminates on the minor duodenal papilla
 Vasculature
o Cranial pancreaticoduodenal aa.
o Caudal pancreaticoduodenal aa.
Pelvic Cavity
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Muscles of pelvic diaphragm
 Levator ani m.
 Coccygeus m.
Inguinal canal
 Intermuscular space b/w the external and internal abdominal oblique mm.
 Contains:
o External pudendal a., genitofemoral n., cremaster m., vaginal tunic (contains spermatic
cord) or vaginal process
 Superficial inguinal ring
o B/w aponeurosis of external abdominal oblique m. and inguinal ligament
 Deep fascia that merges with aponeurosis of external abdominal oblique m.
 Deep inguinal ring
o Area b/w the caudal margin of the internal abdominal oblique m. and inguinal ligament
o Transmits:
 Vaginal process (female)
 Cremaster m., external pudendal vessels, genitofemoral n., and efferent lymphatics
from the superficial inguinal lymph nodes (male)
 Vaginal ring
o Concentric ring formed by evagination of parietal peritoneum at the level of the deep
inguinal ring
o Encloses the spermatic cord (male) or round ligament of the uterus (female)
Muscular lacuna
 Space b/w ilium and inguinal ligament that transmits the femoral n. and iliopsoas m.
Vascular lacuna
 Space b/w pubic bone (caudally) and inguinal ligament (cranially) that transmits:
o Femoral a.
o Femoral v.
o Deep femoral a.
o Deep femoral v.
o Efferent lymphatics from popliteal lymph node
Kidneys
 Right kidney
o Lies in contact with the caudate process of the caudate lobe of the liver
o Lies cranial to the left kidney
 Left kidney
o Lies caudal to the right kidney
o Capsule (smooth fibrous covering)
o Hilus
 Entry point for renal vessels, lymphatics, nerves, and ureter
 Renal a. (may be more than one)
- Branches into interlobar arteries that define renal pyramids
 Renal v.
- The left gonadal v. (testicular/ovarian v.) drains into the left renal v. If the
left kidney is to be removed, it is important to ligate the renal vessels close
to the kidney to still allow the gonadal v. drain into the caudal vena cava
o Ureters
 Connect kidneys to bladder
o Outer cortex
 Contains renal corpuscles and tubules
o Inner medulla
 Contains collecting ducts and nephron loops
 Renal pyramids
- Divisions of medulla made by interlobar aa.
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Renal papilla
- Apex of each renal pyramid that contain ends of collecting ducts
- Urine drips from renal papilla into renal pelvis
- Renal crest (only in some animals)
 Ridge formed by the renal papilla of fused renal pyramids
 Renal pelvis
- Expanded sections of proximal ureter into which drops urine from papilla
- Pelvic recesses
 Small diverticulae that extend from renal pelvis along interlobar
aa. (b/w the renal pyramids)
- Renal sinus
 Fat-filled area at the renal pelvis that surrounds the structures
entering the hilus
Arcuate arteries
 Branches of interlobar aa. that form at junction of renal cortex and medulla
Adrenal glands
 Left adrenal
 Right adrenal
o Much harder to remove b/c it is attached to the caudal vena cava, which must not be cut
Urinary bladder
 Trigone of the bladder
o Triangular-shaped area of the dorsal bladder formed by drawing a line b/w the ureteral
openings and from each of these openings to the urethral opening
 Lateral ligaments of bladder
o Attach lateral surfaces of urinary bladder to lateral abdominal walls
o Carry ureters
o These ligaments carry the umbilical aa. (fetus)
o Part of umbilical aa. remain patent and travel from the internal iliac aa. to bladder (adult)
 These umbilical aa. supply blood to the bladder (carnivores)
o Part of umbilical aa. become round ligaments of the bladder (adult)
 Fibrous cords that travel from bladder to umbilicus
 Median ligament of the bladder
o Attaches ventral midline of bladder to ventral abdomen just caudal to the umbilicus
o (Fetus) contains the urachus
o (Adult) sometimes contains urachus remnant
Uterus
 Broad ligament of the uterus
o Lateral folds of peritoneum that suspend ovaries, oviducts, uterine body and horns
o Divided into 3 parts (mesometrium, mesovarium, mesosalpinx)
 Mesometrium
o Portion of broad ligament that suspends the uterus
o Contains vessels, nerves, and lymphatics of the uterus
o Round ligament of the uterus
 Remnant of the gubernaculum
 Ends at the vaginal process
 External genitalia
o Vulva
 Labia
 Clitoris
- Glans clitoris (male homologue is the penis)
- Fossa clitoris (contains the glans clitoris)
 Vestibule
- Area of vulva from labia to urethral orifice
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Urethral tubercle
Vestibular bulbs (male homologue is bulbus glandis)
 Elongated masses of erectile tissue
 Swell during mating to help produce the “tie”
Vagina
o Dorsal median fold
 Fold of mucosa that hangs from the dorsal midline in the cranial vagina and greatly
reduces the diameter of the vaginal lumen, restricting approach to the lumen
Cervix (muscular structure at neck of uterus)
o Cervical canal (very narrow passage through the cervix)
Vaginal process (female)
o Evaginated parietal peritoneum that extends outside the superficial inguinal ring
Ovary
 Ovarian bursa
o Visceral peritoneal sac that surrounds and suspends ovaries
o Slit-like opening into peritoneal cavity on the medial aspect
 Ova are transiently released into peritoneal cavity before taken up by oviduct
 Mesovarium
o Portion of broad ligament in which sits the ovary
o Forms medial wall of ovarian bursa (dog)
 Mesosalpinx
o Portion of broad ligament containing the oviduct
o Forms lateral wall of ovarian bursa (dog)
 Suspensory ligament
o Attaches ovary to body wall
 Proper ligament of the ovary
o Remnant of gubernaculum
o Attaches ovary to uterine horn
Scrotum (several layers)
 Tunica dartos
o Smooth m. of scrotal wall
o Contraction and relaxation involved in temperature regulation of testis
 Cremaster m.
o Extension of internal abdominal oblique m. that attaches to parietal visceral tunic
o Its contraction and relaxation is involved in temperature regulation of the testis
o Supplied by genitofemoral n.
 GSE, GSA (male)
 GSA only (female)
 Vaginal tunic
o Homologue of vaginal process in female
o Outpocketing of peritoneum that extends through the inguinal canal
o Parietal layer
o Visceral layer (covers testis)
 Contains the spermatic cord, which contains several structures
- Ductus deferens, ductus deferens vessels, testicular vessels, testicular
lymphatics, smooth m. bundles, testicular autonomic nerves (GVA, GVE)
- Mesorchium (contains testicular vessels)
 Pampiniform plexus
o Counter-current heat exchange between testicular vessels
o Involved in thermoregulation of testis
- Mesoductus deferens (contains ductus deferens)
Testis
 Produce sperm
 Covered by touch CT, tunica albuginea
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Epididymis
 Collects and stores sperm made in testis
 Head (cranial)
 Body
 Tail (caudal)
o Proper ligament
 Attaches testis to the tail of the epididymus
o Ligament of the tail of the epididymus
 Attaches epididymus to the wall of the scrotum
Prostate gland (only accessory sex organ of the dog)
 Produces seminal fluid
 Ductus deferens enters the prostatic urethra after passing through the prostate gland
o Colliculus seminalis
 Longitudinal ridge on the dorsal aspect of the prostatic urethra where the ductus
deferens enters
Prepuce
 Tubular sheath of integument reflected over the glans penis
 Fornix of prepuce
o Deep recess where internal layer of prepuce is reflected over the glans penis
Penis (musculocavernous type)
 Comprised of erectile tissue divided into 3 regions:
o Root
 Crura of penis (left and right)
- Each crus is composed of vascular sinus tissue, corpus cavernosum, that
is covered by an ischiocavernous m. (attaches crus to ischial tuberosities)
 Bulb of penis
- Root of the penis between the crura
- Composed of corpus spongiosum (vascular sinus) covered by the
bulbospongiosus m.
o Body
 Blood sinuses covered by tunica albuginea
- Thick CT that completely surrounds penis and paired corpora cavernosa
- Maintains erection by constriction of deep dorsal v. of penis
o Glans
 Bulbus glandis
- Dorsal extension of the corpus spongiosum (vascular erectile tissue)
- Main male contribution to “tie”
 Pars longa glandis
 Os penis (membranous bone)
- Formed from ossification corpora cavernosa
- Urethral groove
 Retractor penis m.
 Ischiourethralis m.
Rectum
 Paranal sinus (anal gland)
o Has 2 anal sacs that lie laterally between the internal and external anal sphincter mm
 External anal sphincter (striated skeletal muscle)
o Innervated by the caudal rectal branch of the pudendal n.
Peritoneal reflections
 Specific regions of the abdomen where the peritoneum forms folds and pouches
 Pararectal fossa (paired)
o Space between dorsal rectum and hypaxial muscles
o Bilateral pouches separated by mesorectum
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Rectogenital pouch
o Space between ventral rectum and genital tract
 Genitovesicular pouch
o Space between the genital tract and urinary bladder
 Pubovesicular pouch (paired)
o Spaces between the ventral floor of the pelvis and urinary bladder
o Spaces separated by the median ligament of the bladder
Branches of the Abdominal Aorta
- Lumbar aa. (paired)
 Extend dorsally from aorta
 Supply the meninges (spinal branches) and muscles/skin above vertebra (dorsal branches)
- Celiac a. (unpaired)
 Hepatic a.
o 1-5 hepatic branches supply the liver
o Right gastric a.
 Anastomoses with left gastric a.
 Supplies lesser curvature of stomach
o Gastroduodenal a.
 Right gastroepiploic a.
- Anastomoses with left gastroepiploic a.
- Supplies greater curvature of stomach and greater omentum
 Cranial pancreaticoduodenal a.
- Follows descending duodenum
- Anastomoses with caudal pancreaticoduodenal a.
- Supplies duodenum and adjacent right lobe of the pancreas
 Left gastric a.
o Supplies both lesser and greater curvatures of stomach
 Splenic a.
o Left gastroepiploic a.
 Supplies the greater curvature of stomach
- Cranial mesenteric a. (unpaired)
 Common trunk for the colon
o Ileocolic a.
 Middle colic a.
- One branch supplies descending colon (anastomoses with left colic a.)
- One branch supplies transverse colon
 Right colic a.
- Supplies ascending and transverse colon
 Colic a.
- Supplies ascending colon
 Cecal a.
- Supplies cecum
- Antimesenteric a.
 Supplies antimesenteric side of ileum
 Mesenteric ileal a.
- Supplies mesenteric side of ileum
o Caudal pancreaticoduodenal a.
 Supplies descending duodenum and right lobe of pancreas
o Jejunal aa.
 Form arcuate blood supply to jejunum
- Common trunk of the phrenicoabdominal a. (paired)
 Cranial abdominal a. (paired)
o Supplies dorsocranial musculature of abdomen
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Caudal phrenic a. (paired)
o Supplies caudal diaphragm
- Renal aa. (paired)
 May be more than one (important surgically b/c must ligate all in a nephrectomy)
 Right renal a. arises cranial to the left b/c of cranial position of right kidney
- Gonadal aa. (paired)
 Right gonadal aa. enter the caudal vena cava
 Left gonadal aa. usually enter the left renal v. (important surgically)
 Ovarian a.
o Branches that supply ovary and bursa
o Branches that supply uterine tube and horn (anastomoses with uterine a.)
 Testicular a.
o Lies within mesorchium (along with testicular v. and n.)
- Caudal mesenteric a. (unpaired)
 Left colic a.
o Supplies descending colon (anastomoses with middle colic a.)
 Cranial rectal a.
o Supplies cranial rectum (anastomoses with middle rectal a.)
- Deep circumflex iliac a. (paired)
 Supplies caudodorsal musculature of abdomen
 Travels with lateral cutaneous femoral n. (AZ on lateral flank)
Portal Venous System
- Portal v.
 Located in the hepatoduodenal ligament at the ventral border of the epiploic foramen
 Carries venous blood to the liver from abdominal viscera (stomach, intestines, pancreas, spleen)
 Blood passes into hepatic sinusoids before exiting via the hepatic vv.
- Hepatic v.
 Drains 4 major veins
o Gastroduodenal v. (within the mesoduodenum)
 Drains pancreas, stomach, duodenum, greater omentum
o Splenic v.
 Drains spleen, stomach, pancreas, greater omentum
 Recieves the left gastric v. (drains lesser curvature of stomach)
o Cranial mesenteric v. (terminal branch of portal v.)
 Drains caudal duodenum, jejunum, ileum, pancreas (right lobe)
o Caudal mesenteric v. (terminal branch of portal v.)
 Drains cecum and colon (ascending, transverse, descending)
Branches of the Pelvic Aorta
- External iliac a. (paired)
 Arises from aorta at ~L6/L7
 Deep femoral a. (only branch of the external iliac a.)
o Caudal epigastric a.
 Supplies rectus abdominus, oblique and transverse mm.
o Caudal superficial epigastric aa.
 Supply superficial musculature, mammary glands, and skin
o External pudendal a.
 Femoral a. (passes through the vascular lacuna)
- Internal iliac a. (paired)
 Umbilical a.
o Patent in carnivores to supply the bladder
o Remnant is the round ligament of the bladder
 Caudal gluteal a.
o Supplies muscles of the thigh and external pelvis
 Internal pudendal a.
Vaginal a.
 Uterine a.
o Prostatic a.
o Continuation of internal pudendal a.
 Caudal rectal a.
 Artery of the penis (gives rise to 3 principal vessels of the penis)
- Artery of bulb of penis
 Enters corpus spongiosum
- Deep artery of penis
 Enters corpus cavernosum
- Dorsal artery of penis
 Runs along dorsal penis body to the level of the bulbis glandis
where it branches to supply the pars longa glandis and prepuce
- Median sacral a. (unpaired)
 Termination of the aorta
Nerves of Abdomen
- Vagus n. (paired)
 Carries preganglionic axons of the PNS from the head to the thoracic inlet via the vagosympathetic
trunk. When this trunk reaches the middle cervical ganglion, the vagus splits from the sympathetic
trunk. Both left and right vagus nn. continue caudally in the mediastinum, sending off branches to
the heart, lungs, and bronchi. They then split into dorsal and ventral branches, which unite to form
dorsal and ventral vagal trunks, which both pass through the esophageal hiatus (esophageal plexus)
to innervate viscera in the abdominal cavity
o Dorsal vagal trunk
 Union of dorsal vagal branches (left/right) on the dorsal surface of the esophagus
 Celiac branch (branches at esophageal plexus)
- Contributes to the formation of the celiac and cranial mesenteric plexuses
- Branch acts as a “shortcut” for the vagus, allowing it to reach the small
intestine and colon quickly
o Ventral vagal trunk
 Union of ventral vagal branches
 Vagus n. terminates is the left colic flexure (transverse  descending colon)
- Splanchnic nn.
 Preganglionic sympathetic neurons from caudal thoracic and lumbar portions of the sympathetic
trunk that do not synapse on chain ganglia but travel to prevertebral ganglia and continue with
blood vessels to innervate viscera within the abdominal cavity
 Major splanchnic n. and minor splanchnic nn. (sometimes present)
o Leaves the sympathetic chain ganglia to innervate the adrenal and celiacomesenteric
ganglia and plexuses
o In an adrenalectomy, cut sympathetic fibers can result in some sympathetic deficits in
abdomen. However, lumbar splanchnic nn. can be preserved so bladder and reproductive
innervation is not disrupted
 Lumbar splanchnic nn.
o Arise from L2-L5 chain ganglia to supply the celiac, adrenal, aorticorenal, cranial
mesenteric, and caudal mesenteric ganglia and plexuses (all paravertebral ganglia)
- Abdominal aortic plexuses and ganglia
 Contain both pre- and postganglionic sympathetic (via splanchnic nn.) and preganglionic
parasympathetic fibers (via vagus n.)
 Celiacomesenteric plexus
o Contains the closely-associated celiac and cranial mesenteric ganglia and plexuses
o Celiac ganglia
 Travels with celiac a. as the celiac plexus
o Cranial mesenteric ganglia
 Travels with cranial mesenteric a. as a plexus
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Caudal mesenteric ganglia
o Most caudal prevertebral ganglion. All preganglionic sympathetics supplying structures of
the pelvic cavity (bladder and reproductive organs) synapse at this ganglion and send
postganglionic fibers through the pelvic plexus via the hypogastric nn. (left and right)
Pelvic Nerves
- Pudendal n.
 Carries GSE to external genitalia
o Caudal rectal n.
o Perineal
o Dorsal n. of the penis (clitoris)
 Innervated the external sphincter m. of the bladder and is involved in voluntary voiding
- Pelvic plexus
 Contains postganglionic sympathetic fibers (via hypogastric n.) and pre- and postganglionic
parasympathetic fibers (via the pelvic n.)
 Hypogastric n. (paired)
o Arises from caudal mesenteric ganglia and carries postganglionic sympathetic fibers
(GVA, GVE) to the pelvic plexus
o Important for the filling phase of bladder
 Relaxation of detrusor m. via ß-adrenergic receptors
 Contraction of internal sphincter m. via œ-adrenergic receptors
o Damage will result in inability to fully expand bladder fully (frequent urination)
 Pelvic n.
o Arises from ventral branches of sacral spinal nn. and carries preganglionic parasympathetic
fibers (GVE) to the pelvic ganglion/plexus to supply structures of the pelvic cavity
o Important in micturition
 Contraction of detrusor m.
 Relaxation of internal sphincter m.
- Pelvic ganglia
 Carries only pre-(mostly) and postganglionic parasympathetic fibers (via pelvic n.)
Lymph nodes
- Medial iliac lymph node
 Located b/w the deep circumflex iliac a. and external iliac a.
 Clinically important as it is the final lymph collection point for pelvic viscera and limbs
- Superficial inguinal lymph nodes
 Drain the testes
- Mesenteric lymph nodes
