Medical Gross Anatomy: Pelvic Anatomy Fall 2008 Goals & Objectives I. II. Goal: To understand the general anatomical design of the human pelvis through careful examination of the following objectives: The student will: 1. Understand the overall composition, morphology, & function of the human pelvis. (Each section will be described in more detail throughout the objectives. However, it will be necessary to refer to your slides for some pictures and further clarification): a. Composition Pelvic girdle and floor Pelvic organs Perineum Neurovascular structure b. Morphology: bowl shaped with skeletal walls, a muscular floor c. Function: Provide space, support, and protection to viscera Distal urinary tract (bladder and urethra) Distal digestive tract (rectum and anus Reproductive tracts Goal: To understand the anatomy of the pelvic girdle, in terms of its composition, bony landmarks, pelvic sex differences, types of fractures, and joints through careful examination of the following objectives: The student will: 1. Learn the names & characteristics of bones that form the pelvic girdle and os coxae. a. Composition of the pelvic girdle: Os Coxa (2 parts- a right os coxa and a left os coxa): hip or pelvic bone of irregular shape which consists of 3 bones Ileum Ischium Pubis b. Sacrum: 5 fused vertebrae Sacral canal: longitudinal space and protection for the spinal nerves Anterior and posterior sacral foramina: connect with the spinal canal for the spinal nerves Promontory: anterior margin of the body c. Coccyx “tail bone”- 3 or four fused vertebrae 1|Page 2. Be able to determine the anterior, posterior, medial, & lateral surfaces of the os coxae. a. Lateral surface: Acetabulum: cup shaped articular surface for the head of the femur Obturator foramen: largest foramen in the body; membrane-covered for muscle attachment b. Posterior margin: Greater sciatic notch on the superior part of the posterior margin Lesser sciatic notch inferior to spine Ischial spine separates the notches Posterior superior iliac spine (PSIS): terminal point of the iliac crest Posterior inferior iliac spine located above the greater notch Ischial tuberosity: rough and curved, the “sit” bone, attachment for hamstrings c. Anterior surface: ASIS AIIS Superior pubic ramus Pubic tubercle 2|Page d. Superior Margin: Iliac crest: prominent superior ridge e. Inferior margin: Ischial ramus Inferior pubic ramus f. Medial surface: Iliac fossa: broad, fan shaped Portions of the pelvic brim: Arcuate line: lateral pelvic brim Pectin pubis: anterolateral pelvic brim Pubic crest: anterior brim 3. Learn the names and locations of the bony landmarks of the os coxae and will be able to specify the ones that can be palpated. a. PSIS, ASIS, ischial tuberosity, sacrum, iliac crest 4. Learn how to correctly orient the pelvic girdle line in the anatomical position. a. The pelvic girdle should be tilted posteriorly about 40 degrees downward b. The ASIS and pubic tubercle line up in the same coronal plane 5. Be able to correctly sex a pelvic girdle through an analysis of observations concerning various dimorphic features of the pelvis and will know the causes for sexual dimorphism of the human pelvic girdle. 3|Page a. Female Appears less massive, contains less prominent markings and the greater sciatic notch is wider than the thumb Pubic angle is wide (>100 degrees) An anatomical compensation for childbirth; need for a birth canal b. Male Appears more massive, contains more prominent markings, greater sciatic notch is thumb-sized The pubic angle is narrow (<80 degrees) 6. Know the morphological classes of the human pelvic inlet and which ones are normally expected for the male and female. a. Male: smaller inlet Android: heart shaped Anthropoid: oval in mid-sagittal direction b. Female: larger inlet Gynecoid: oval in transverse direction Platypelloid: more extreme transverse diameter 7. Learn the three measures of pelvic diameters. a. Transverse: widest, largest diameter (131 mm) b. Conjugate: promontory to pubic symphysis; smallest diameter (112 mm) c. Oblique: diagonal (125 mm) 8. Learn the pelvic variations that would increase the probability of the need for a cesarean delivery. a. A woman of very small frame might require a cesarean delivery if the physician feels natural birth could harm her or the baby. The pubic angle is usually the determinant measurement. 9. Know the locations of probable hip fractures resulting from different forces. (Dr. Terrell only briefly mentioned this in lecture. I’ll list the most common forms of hip fractures from Wikipedia for your reading pleasure 4|Page a. Many subtypes of fractures about the hip joint are colloquially known as 'hip fractures'. Although a true hip fracture involves the joint, the following four proximal femur fractures are commonly referred to as 'hip fractures'. The differences between them are important because each is treated differently. b. Femoral head fracture denotes a fracture involving the femoral head. This is usually the result of high energy trauma and a dislocation of the hip joint often accompanies this fracture. c. Femoral neck fracture denotes a fracture adjacent to the femoral head in the neck between the head and the greater trochanter. These fractures have a propensity to damage the blood supply to the femoral head, potentially causing avascular necrosis. d. Intertrochanteric fracture denotes a break in which the fracture line is between the greater and lesser trochanter on the intertrochanteric line. It is the most common type of 'hip fracture' and prognosis for bony healing is generally good if the patient is otherwise healthy. e. Subtrochanteric fracture actually involves the shaft of the femur immediately below the lesser trochanter and may extend down the shaft of the femur. 10. Learn the name, location, articulation, type of joint, and ligaments for each joint of the pelvic girdle. Include lumbosacral joint abnormalities. a. Lumbosacral Joint @ L5-Si Movement at two joints Zygapophysical joint: synovial planar type between articular processes Intervertebral joint: cartilaginous type between bodies of LV & S1 with intervertebral disk Ligaments Iliolumbar ligament: LV transverse process to iliac crest Lumbosacral ligament: LV transverse process to sacrum Anterior longitudinal ligament: lumbar bodies to sacral bodies b. Sacroiliac Joint: attaches sacrum and os coxae (at the ilium) Transmits forces between vertebral column and lower limbs Synovial type joint Articular surfaces are jagged to interlock which provides more strength Ligaments: Anterior and posterior sacro-iliac: broad, joint capsule Interosseus sacro-iliac: deep and strong; in roughened surfaces of the joint 5|Page c. Pubic symphysis: anterior at the 2 os coxae Cartilaginous type joint Ligaments: Superior and inferior pubic ligaments Stretches during childbirth 11. Be able to identify bony structures on a radiograph. See this website for an interactive “show and tell” of the pelvic radiograph (it also has the same thing for all parts of the body!!) http://ect.downstate.edu/courseware/rad-atlas/Pelvis/1PelRad.html http://ect.downstate.edu/courseware/rad-atlas/index.html III. Goal: To understand the anatomy of the pelvic cavity walls and floor through careful examination of the following objectives: The student will: 1. Understand the morphology, regions, & walls of the pelvic cavity. a. Muscles of the female pelvis b. Muscles of the male pelvis 6|Page 2. Know the boundaries of the pelvic inlet and outlet of the true pelvis. a. Pelvic Brim: False (greater) pelvis: inferior part of abdomen True (lesser) pelvis: forms the pelvic cavity Pelvic inlet: circular shaped superior opening Boundaries: Posterior: sacrum Anterior: pubic symphysis lateral: distinct bony rim on pelvic bone Contents: body of vertebra S1projects thru inlet as the sacral promontory. On each side of this vertebra, wing-like processes called the alae contribute to the margin of the pelvic inlet fetus passes thru pelvic inlet during childbirth 7|Page Pelvic outlet: diamond shaped inferior opening Boundaries: Anterior: pubic symphysis posterior-point of the coccyx lateral: ischial tuberosities Contents: terminal parts of the urinary and gastrointestinal tracts and the vagina pass through the pelvic outlet 3. Learn the bone, ligaments, & muscles of the lateral walls of the pelvic cavity. a. Bone: os coxae, sacrum, coccyx b. Ligaments: enclose sciatic notches to form sciatic foramens and stabilize sacrum with os coxae Sacrospinous ligament: sacrum to ischial spine (function: divides greater and lesser sciatic foramen) Sacrotuberous ligament: sacrum to ischial tuberosity (forms posterior border of sciatic foramens c. Muscles: Obturator internus: exists through Is. sciatic foramen Piriformis: splits greater sciatic foramen into 2 openings 4. Learn the pelvic cavity apertures & their contents. a. Obturator canal: small slit on the lateral margin of Obturator internus Obturator nerve, artery and vein exit to the medial thigh b. Greater sciatic foramen: superior to piriformis superior gluteal nerve, artery, and vein c. Greater sciatic foramen: inferior to piriformis Inferior gluteal nerve, artery, and vein, and sciatic nerve d. Lesser sciatic foramen Obturator internus muscle Pudendal nerve and internal pudendal nerve, artery, and vein 5. Understand the structure that covers the floor of the pelvic cavity & outlet and its associated functions. (Pelvic Diaphragm) a. Function: to support the pelvic viscera, resist changes in intra-abdominal pressure, and allow for voluntary control of defecation b. Composition: Coccygeus: triangle shaped to ischial spine; forms and supports the posterior diaphragm Levator ani: bowl-shaped structure that joins in the midline Puborectalis: medial- forms the puborectal sling which maintains the anorectal angle and prevents defecation Pubococcygeus- middle Iliococcygeus- lateral Genital hiatus: a midline gap in anterior levator ani to allow for passage of urethra and vagina 6. Know the composition of, identify, and function of the pelvic diaphragm, levator ani, and the genital hiatus. a. See above 7. Know the major structures that pass through each of the pelvic inlet and outlet. a. See above 8|Page IV. 8. Learn the types & functions of pelvic fascia and fascial ligaments. a. Pelvic Fascia Types: Parietal: lines inner muscle cavity walls and floor Visceral: covers pelvic visceral and vessels Endopelvic: filler or packing between viscera b. Pelvic Fascial Ligaments: thickening of fascia to provide passive support for the pelvic organs Tendinous arch of pelvic fascia: bilateral band from pubis to sacrum along floor next to midline Pubovesical (puboprostatic) ligament: anterior most; connects bladder (prostate) to pubis bone Sacrogenital (uterosacral): posterior most; connects bladder or cervix and vagina to sacrum Transverse cervical ligament: attaches cervix and vagina to lateral pelvic wall Hypogastric sheath: conduit between lateral wall and pelvic viscera for neurovascular, uteters, vas deferens Goal: To understand the anatomy of the pelvic cavity viscera through careful examination of the following objectives: The student will: 1. Learn the ureters’ composition, function, extent, and course through the pelvic cavity. a. Composition: retroperitoneal muscular tubes (25cm) b. Function: transport urine via peristaltic constrictions every 25 seconds c. Extent: only distal half is in the pelvis Enter pelvic inlet anterior to the bifurcation of the common iliac Course down in pelvic wall Posteriolateral sides of bladder 2. Learn the bladder’s composition, function, anatomical surfaces, stabilizing supportive ligaments, wall structure, and internal structure. a. Morphology: rounded, 3-sided pyramid shape b. Surfaces: Apex: anteriorly to top of pubic symphysis Base: inverted triangle posteroinferiorly Internal structure of base: Trigone: smooth triangular area Ureteric orifices and sphincters: upper corners surround ureters; constrict during micturation Internal urethral orifice and sphincter: encircle urethra; relaxes during micturation Uvula: upward bulge of Trigone from prostate Superior surface: balloons upward to the abdomen Neck: most inferior part; site of urethra attachment c. Composition of wall: Rugae: distensible folds of mucosa/submucosa Detrusor muscle: muscular coat with 3 layers d. Stabilizing/supportive ligaments: Pubioporstatic (pubovesical) ligaments: thickened endoscopic fascia from neck to pubis bones Median umbilical ligament: attaches apex to anterior abdominal wall 9|Page 3. Learn the male urethra’s extent and segments. a. Morphology: 20 cm; bends 2 times b. Male urethra is divided into four segments Preprostatic: 1 cm at the base of the bladder to the prostate; with the internal urethral sphincter Prostatic urethra: 4 cm surrounded by prostate Urethral crest: longitudinal midline fold Urethral sinus (2): on side of crest Receives ejaculatory and prostatic ducts Membranous urethra: passes through perineum external urethral sphincter; made of skeletal muscle (voluntary control) Spongy (penile) urethra: In root and body of penis (corpus spongiosum) Bends 2x at bulb and navicular fossa Receives ducts from cowper’s (bulbourethral) glands External urethral orifice: a slit at the terminal end 4. Learn the female urethra’s extent, attachment, and why they are more susceptible than men to urinary tract infections a. Morphology: short, about 4 cm b. Attaches to anterior wall of vagina c. External urethral orifice opens in the vestibule d. The relatively short length of the urethra in women makes them more susceptible than men to bladder infection. 5. Learn the rectum’s location, boundaries, transverse folds, and anal canal features. a. Location: most posterior pelvic organ; anterior to sacrum b. Boundaries: rectosigmoid junction: to sigmoid colon at S3 anorectal junction: to anal canal at tip of coccyx anorectal flexure- 80 degree angle, maintained by puborectalis sling c. wall structure transverse rectal folds (3): valves that retain fecal mass when passing gas lacks taeniae coli and omental appendicies d. anal canal: terminal part of GI tract; passes through pelvic floor and perineum mucosa folds anal columns and sinuses: longitudinal ridges and grooves that release mucous passages internal and external anal sphincters: smooth and skeletal muscle in two layers anus (anal aperture): termination of anal canal with perianal skin 6. Understand the general design and comparative anatomy of the male and female reproductive systems. General Structure Male Female 1. Primary organ testes ovaries 2. Tract organs 10 | P a g e vas deferens ejaculatory duct urethra uterine tubes uterus vagina 3. Accessory glands seminal vesicle prostate bulbourethral mammary paraurethral vestibular 4. External genitalia scrotum& penis vulva 7. Learn the composition of the testes in terms of its protective coat, functional tissues, and conducting tubules. a. Protective coats: Tunica vaginalis: closed sac of the peritoneum covering anterior aspects and sides Tunica albuginea: Connective Tissue capsule-lobes b. Functional tissues: seminiferous tubules- highly coiled (~600): site of meiotic sperm cell formation Interstitial cells – between tubules and secrete testosterone c. Additional tubules: rete testis- posterior testes; collecting chamber from seminiferous tubules Efferent ductules- (~15)- in posterior capsule, delivers immature sperm to epididymis. 8. Learn the structures & course of the male reproductive tract. a. Epidydymis: coiled tube in posterior scrotum, Divided into 3 sections the head, body, and tail b. Function: storage, growth, and maturation of the sperm c. Ductus (vas) Deferens- long smooth muscular tubes, from tail of epidydymis to ejaculatory duct. spermatic cord, inguinal canal, deep to inf. epigastric a, crosses ureter, between bladder & rectum d. Ejaculatory duct- short and passes through the prostate, formed when vas deferens and duct of seminal gland join. Empties into prostatic urethra 9. Learn the male accessory organs: their location, morphology, and function. For the prostate gland, also learn the structures in the prostatic urethra and the impacts of prostatic hypertrophy & cancer. a. Seminal vesicles- elongated lobular sacs (5cm) Located lateral to vas deferens at the base of the bladder. Secrete seminal fluid- alkaline, fructose and prostaglandins- bulk of semen b. Prostate- large accessory gland, Located- posterior to pubic symphysis and anterior to rectum Function by secreting milky and acidic to fluid which helps to maintain sperm health Morphology: Conical shaped (3cm x 4cm) c. 5 lobes of the prostate Seminal colliculus- expanded urethral crest, Prostatic utricle- embryological remnant of the vagina Openings of ejaculatory ducts- just below utricle- one on each side. Urethral sinus- on either side of the colliculus, has openings of the prostatic ducts. d. Protective coats- prostatic veins between layers. 11 | P a g e Prostatic sheath- outer- pelvic fascia and continuous with puboprostatic ligs. Prostatic capsule- surface of the gland e. During prostate cancer prostatic enlargement occurs- nocturia, dysuria, urgency. This happens to all elderly males f. Middle lobe- prostatic urethra and interior to urethra sphincter g. Bulbourethral (cowper’s) glands (2) - pea-sized paired glands in deep perineal space Function: mucosal lubrication of pre-ejaculatory emission spongy urethra 10. Learn the location, morphology, ….. a. Ovaries: almond like shape- inferior to pelvic inlet on lateral wall. b. Ligaments: Suspensory ligaments- peritoneum fold and conduit attaches ovary to lateral pelvic wall and contains Ovarian nerve, artery, vein, and lymphatics. Ovarian ligaments- to lateral wall of uterus Broad ligaments- sheet like fold of peritoneum from lateral pelvic cavity wall to ovary, uterine tube, and urethra wall. c. Two functional tissues: Cortex: matures and releases ovum (oocyte) Medulla: secretes estrogen and progesterone d. Uterine tubes: extend from uterus superiorly to lateral pelvic cavity Segments: Infundibulum- with fimbrae- collect oocyte from ovary Ectopic pregnancy: external fertilization Ampulla- middle- site of fertilization Isthmus- connects to uterus e. Uterus: tilted anteriorly over the bladder. Anterior to rectum. Composition of the uterine wall: Peritoneum- peritoneum connective tissue Myometrium**- thick smooth muscle tissue, makes up the majority of the uterine wall Endometrium- highly glandular lining of the wall- provides initial nourishment to embryo f. Four regions of the uterus: Fundus: domed end Body: central with uterine cavity Isthmus: between body and cervix –narrowing cavity Cervix: inferior portion with central canal Internal os: opening with uterus External os: opening into vagina g. Fascial ligaments: Broad and ovarian ligaments 12 | P a g e V. Round ligaments: body of uterus to deep inguinal ring through inguinal ring through inguinal canal to labium majus Pubocervical ligaments: anterior from cervix over bladder to pubis Transverse cervical ligament: lateral pelvic wall Uterosacral ligament- posterior pelvic wall h. Recto-uterine (recto-vesical) fold or pouch- lowest portion of abdominopelvic-cavitycollection of fluids i. Vagina: Titled through perineum and pelvic cavity between bladder and rectum. Composition of wall: fibromuscular tube with rugae and glands (collapsed) Fornix: recess between cervix and vaginal wall Vaginal sphincters: Rectovesicalis- rectum to lateral vagina to bladder Pubovaginalis- pubis to anterior vaginal wall Urethrovaginal- encircles Bulbospongiosis- in perineum Goal: To understand the anatomy of the perineum through careful examination of the following objectives: The student will: 1. Understand the general concept, subdivisions, and boundaries of the perineum. a. Concept: Series of tissue layers inferior to pelvic floor & attached to pelvic outlet. It’s the region between the thighs and includes the genitalia. b. Boundaries: pubic symphysis ischial tuberosities Coccyx; forming a diamond shape. 2. Learn the anal triangle’s boundaries and contents. a. Boundaries: Line between the ischial tuberosities, the sacrotuberous ligaments, and the coccyx. b. Contents: anal aperture, external anal sphincter, and the ischio-anal fossae. 3. Learn the strata of the urogenital triangle including the specific locations of the perineal membrane and superficial & deep perineal pouches. a. strata going from deep to superficial are: pelvic diaphragm, deep perineal pouch, perineal membrane, superficial perineal pouch, and the superficial fascia and skin. 4. Learn the contents of the deep perineal pouch including the content differences of muscles & glands in males & females a. deep perineal pouch contains the bulbsurethral glad (also known as the cowper’s gland) in males. b. Both males and females also have a deep transverse perineal muscle and an external urethral sphincter. c. Females also have two additional muscles, the urethrovaginalis sphincter and the compressor urethrae 5. Learn the contents (erectile tissues, glands, & muscles) of the superficial perineal pouch. a. Males: it contains the crura of the penis and the bulb of the penis. 13 | P a g e VI. b. Females it contains the bulbs of vestibule, the greater vestibular glands, and the glands of the clitoris. c. Both males and females have ischiocavernosus muscles, bulbospongiosus muscles, and a superficial transverse perineal muscle 6. Learn the structure of the male’s external genitalia (penis & scrotum) a. root, shaft, and glands the root has the two crura and the bulb of the penis that are attached to the perineal membrane. The shaft is the central part and is supported by the fundiform ligament and the suspensory ligament of the penis. The glans is the cone shaped end of the penis b. Three columns are present throughout the length of the penis, they are a specialized cartilage. The dorsal two are the corpora cavernosa and the corpus spongiosum is the bottom part. c. Remember the penis is erect in anatomical position for naming. 7. Learn the structure of the female’s external genitalia and the glands of the vestibule. a. The vulva is the external genitalia and has 4 parts. The mons pubis is the superior part covered with hair. The labia majora are the lateral skin folds also with hair and attach to the round ligament of the uterus and cover the bulbosponginosus muscle. The labia minora is the medial hairless skin fold that closes and prevents drying. The vestibule is the area between the labia minora and contains three things: the clitoris (erectile tissue and cutaneous sensitivity) the external urethral and vaginal orifices, 3 glands. The three glands are the lesser vestibular glands, the greater vestibular ducts, and the paraurethral glands (female prostate) Goal: To understand the anatomy of the pelvic neurovascular structures through careful examination of the following objectives: The student will: 1. Understand the location, composition, pathway, and function of the sacral plexus. a. Location: lies anterior to piriformis muscle and is covered with pelvic fascia with nerves exiting in greater sciatic foramen (described further below) 2. Learn the composition (spinal nerve contribution), pathway, & function of the somatic nerves of the sacral plexus. a. Composition: ventral rami of branches from spinal n Lumbosacral trunk- L4 & L5 S1-S4 (together with lumbosacral plexus it forms the sacral plexus) 3. Learn the autonomic trunks, nerves, and plexus that serve the pelvic cavity. a. Somatic Nerves Sciatic n- largest; major n of LL Comp: L4-S3 Exits: inferior to piriformis muscle Splits into: Tibial N (L4-S3) and Common Fibular N (L4-S2)—which has two branches: superficial and deep fibular nerves Pudendal N- major nerve of perineum Comp: S2-S4 14 | P a g e Exits: inferior to piriformis muscle, crosses over sacrospinous ligament and re-enters in lesser sciatic foramen. Enters Pudendal canal- medial border of obturator internus muscle— neurovascular bundle Pudendal N in canal divides into: Inf rectal N- near entrance of pudendal canal ishoanal fossa Motor: ext. anal sphincter and levator ani Sensory: skin of anal triangle Dorsal N of penis (clitoris)- descends in pudendal canal and in deep perineal pouch Function: primary sensory nerve of the penis or clitoris Perineal N- descends in canal and superficial perineal pouch and divides into: Deep perineal N- enters deep perineal pouch Motor: muscles of deep and superficial pouches Sensory: vestibule and inferior vagina Superficial perineal N- in superior perineal pouch becomes posterior scrotal or labial N (sensory nerves) b. Pelvic Autonomics Sacral paravertebral trunk (2)- 4 ganglia of the sympathetic trunk in pelvic cavity Courses over ala and descends medial to ant. Sacral foramina Ganglion impar- connects right and left trunks Sacral prevertebral trunk- carries sym, parasym, and visceral afferent fibers for pelvic organs and erectile tissues of perineum Superior hypogastric plexus- anterior to L5: distributes sacral prevertebal fibers to right and left hypogastric nerves, which descend into pelvic cavity and connects with right and left inferior hypogastric plexus. Which is made of right and left hypogastric nerves Pelvic splanchnic N- parasym, S2,3, 4 c. Subsidiary plexuses- inn by inferior hypogastric plx: Rectal plexus- assoc w/ rectum Vesicle plexus- assoc with urinary bladder Uterovaginal (prostatic plexus) – erectile tissue of perineum Cavernous N- from prostatic plexus erectile tissues of penis 4. Understand the three major vessels that serve the pelvic cavity (internal iliac, gonadal, median sacral). a. Internal Iliac Artery: Major artery of the pelvic cavity Origin: bifurcation of common iliac artery at the lumbosacral joint Bifurcation at the pelvic brim to: Anterior trunk: supplies the pelvic viscera, perineum, gluteal region, medial thigh, and placenta Branches to: Umbilical artery- adjacent to pelvic inlet, ascends in anterior abdominal wall to umbilicus 15 | P a g e One branch: superior vesical artery- serves distal ureter, superior surface of the bladder and the ductus deferens Obturator artery- located below the margin of the pelvic brim, descends through Obturator foramen with the nerve above and the vein below; serves medial thigh compartment Inferior vesical (vaginal) artery- inferior bladder, ureter, seminal vesicle, prostate (vagina), and part of rectum Middle rectal artery- serves rectum; anastomoses with superior rectal artery from the inferior mesenteric artery and the inferior rectal artery from the internal pudendal artery Internal pudendal artery- main artery of perineum; passes through greater sciatic foramen inferior to piriformis muscle and re-enters in lesser sciatic foramen Branches to: inferior rectal artery and perineal artery Perineal artery branches to: posterior scrotal (labial) artery, dorsal artery of penis & deep artery of penis (clitoris) Women only: Uterine artery which anastomizes with the ovarian artery Vaginal artery: anastomizes with uterine artery Inferior gluteal artery (terminal branch of anterior trunk), exits in greater sciatic foramen inferior to piriformis to innervate gluteus maximus Posterior trunk: supplies posterior abdominal and pelvic walls as well as the gluteal region of the hip Branches to: Iliolumbar artery which ascends above the pelvic rim along the lumbosacral trunk Iliac branch- serves iliac fossa (iliacus m) Lumbar branch- lower posterior abdominal wall Lateral sacral artery: anterior sacral foramina to serve sacrum and skin Superior gluteal artery- greater sciatic notch, above piriformis to serve the gluteal region (gluteus medius and minimus) b. Gonadal Artery (Testicular or ovarian arteries) Testicular artery: accompanies the ductus deferens into the scrotum, where it supplies the spermatic cord, epididymis, and testis Ovarian artery: enters the suspensory ligament of the ovary, supplies the ovary, and anastomoses with the ovarian branch of the uterine artery c. Median Sacral Artery: an unpaired artery arising from the posterior aspect of the abdominal aorta just before its bifurcation 16 | P a g e Descends in front of the sacrum, supplying the posterior portion of the rectum, and ends in the coccygeal body, which is a small cellular and vascular mass located in front of the tip of the coccyx 5. Learn the branches of and the pelvic organs served by the anterior and posterior trunks of the internal iliac arteries. a. above 6. Understand the patterns of venous drainage of the pelvic cavity a. Most veins follow their arteries b. Internal iliac vein Pelvic Plexuses of veins Dorsum vein of penis (clitoris) Prostatic (vesical) venous plexus- prostate and bladder External rectal plexus c. Non internal iliac veins Internal rectal plexus Gonadal (testicular or ovarian) vein **The left gonadal vein drains to the left renal vein **The right gonadal vein drains to the IVC 7. Learn the names of nodes & patterns of lymphatic drainage of the pelvic cavity. a. Visceral lymphatics Internal and external iliac nodes Common iliac nodes Lateral aortic and preaortic nodes Lumbar trunks Thoracic duct (forms at T12) b. Perineum lymphatics Superficial penis and scrotum (clitoris and labium major) Superficial inguinal nodes External iliac nodes 17 | P a g e