ANATOMY OF PELVIS
Terms
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- piriformis
- arises from anterior surface of sacral vertebrae 2-4; sacral plexus formed on the substance of muscle; almost fills the greater sciatic foramen; tendon passes thru and almost fills lesser sciatic foramen; attaches to greater trochanter; "pear-shaped"
- coccygeus (ischiococcygeus)
- arises from ischial spine and extends back towards the sacrum and coccyx; lies anterior to sacrospinous ligament
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pubococcygeus
(levator ani) - arises from pubis, extends to posterior coccyx; circumscribes urethra, vagina, and rectum; 3 parts: pubourethralis, pubovaginalis, puborectalis
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iliococcygeus
(levator ani) - arises from tendonous arch of levator ani
- tendonous arch of levator ani
- thickened part of obturator internus fascia
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puborectalis
(pubococcygeus) - most medial and anterior fibers of pubococcygeus; attaches to one side fo pubis running posterior takin 90 deg bend around rectal/anal junction and attaches to the other side
- broad ligament
- double layered fold of peritoneum; anterior and posterior leaflets; anterior leaflet-comes over the top of the oviduct and passes posteriorly over ovarian ligament; 4 parts
- 4 parts of broad ligament
- infundibulopelvic (suspensory ligament of ovary); mesoovarium; mesosalpinx; mesometrium <major part>
- uterus
- cornu (horns); fundus (upper part); body; uterine cavity; internal os <about same position as isthmus>; cervix (lower 1/3); external os
- vagina
- smooth muscular tube; lower 1/4 innervated by pudendal n (n of perineum); fornices-surround lips of cervix, to reach rectouterine pouch <Douglas> go thru posterior fornix into most inferior part of peritoneal cavity/also important in infection (abortion)
- oviduct
- ampulla (2/3 of oviduct, where fertilization occurs); infundibulum (funnel)-distal end; fimbria-fingerlike processes on end of infundibulum
- urinary bladder
- surfaces: superior, anterior, posterior; subperitoneal (extraperitoneal); ligaments: pubovesical and pubocervical (female), and puboprostatic (male); lies in retropubiv space (space of Retsius)
- interior aspect of bladder
- detrusal muscle (smooth)-innervated by pelvic splanchnic nn (S2-S4), also called nervi erigentes, which also carry afferent and efferent limbs of bladder emptying reflex arc
- bladder trigone
- area of interior wall of bladder that is smooth-mucosa is so adherent to muscle tissue; bounded by ureters (ureteric orifices) and urethra
- prostate
- triangular shape with base superiorly and apex inferiorly(urogenital diaphragm); 4 lobes: two lateral, anterior, posterior; ejaculatory duct passes thru posterior lobe, dividing in into median and posterior lobe proper
- male urethra
- 3 parts: prostatic, membranous, spongy portions
- anal canal
- 4-5cm; 3 areas:cutaneous, transitory zones, and mucous membrane (5-10 vertical columns-Morgagni's)
- arterial supply of rectum
- superior rectal a (continuation of IMA); median sacral (aorta); middle rectal (internal iliac); inferior rectal (internal pudendal)
- obturator nerve
- only nerve found in pelvis that is branch of lumbar plexus
- sacral plexus
- formed on piriformis muscle; formed by lumbosacral trunk joining with S1-S5
- sciatic nerve
- largest nerve, formed by L4-S4
- pudendal nerve
- almost sole somatic nerve supply of perineum; passes out of greater sciatic foramen (beteen piriformis and coccygeus muscles)then run deep to sacrospinous lig and thru lesser sciatic foramen to give off inferior rectal nerves, then continues into pudendal canal (ischiorectal fossa), gives off posterior scrotal and labial nerves and perineal nerve continues deep to perineal membrance and becomes the dorsal nerve of penis or clitoris
- pelvic splanchnic nerves
- from S2-S4; causes erection (parasympathetics); carry afferent and efferent limbs (bladder reflex arc fibers)
- ischium
- L-shaped, has body and ramus;greater and lesser sciatic notches lying in between ischial tuberosity and ischial spine
- pubis
- body lies medially; pubic crest; superior ramus; inferior ramus, which joins with the single ramus of ischium (ischiopubic ramus), one of the most frequently fractured sites of oscoxy
- pectineal line
- lies in superior and posterior aspect of superior ramus (pubis); pectineus attaches here
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1) sacrospinous lig
2) sacrotuberous lig - 1) is anterior to 2); both help to convert greater and lesser sciatic notches into foramina; extrinsic ligs of SI joint; 1) attaches to ischial spine and coccygeus muscle lies anterior to it.
- Peritoneum related to pelvis (male)
- comes off the anterior abdominal wall and passes onto superior aspect of vesicle of bladder then passes deeply in the interval of the vesicle and rectum and back over anterior and lateral surfaces of rectum--forms most inferior, dependent protion of male peritoneal cavity <rectovesical pouch>; excess liquid in peritoneal cavity called ascites
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Peritoneum-continued
(female) - comes off ant abdominal wall down to superior surface of bladder, hits uterus; change is the intervention btwn urinary bladder and rectum with vagina and cervix; anterior layer runs over ant aspect of uterus and runs over top part (fundus) and is located posteriorly as well; relationship to rectum is similar to in male; 2 spots that are most dependent: 1)rectouterine pouch <pouch of Douglas or cul-de-sac>--inferior to 2)vesicouterine pouch
- Pelvic fascia
- Parietal-a continuation of abdominal transversalis fascia; more or less equal to deep fascia enveloping muscles; visceral-Endopelvic or extraperitoneal fatty tissue; acts as a cushion,and supports and lies adjacent to organs
- 2 thickenings of parietopelvic fascia-used to suture uterus or bladder to lateral wall
- 1) tendinous arc of levator ani-condensation of obturator interin fascia, lies against wall of pelvis; 2) tendinous arc of pelvic fascia-thickening of fascia covering pelvic diaphragm
- divarication
- Separation of normally joined parts, such as the separation of certain abdominal muscles during pregnancy.
- dehiscence
- A bursting open or splitting along natural or sutured lines
- pudendal artery
- gives rise to inferior rectal aa then on to posterior labial aa and on to deep artery of clitoris <homologous structures in male>
- pectinate line
- point where voluntary muscle in external anal sphincter, and involuntary muscle in internal anal sphincter; internal area supplied by pelvic sympathetics and parasympathetics, external by somatic nerves
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suspensory lig of ovary
(infundibulopelvic lig) - part of broad ligament; fold of peritoneum convering anterior aspect of ovarian vessels as cross the pelvic brim
- ovarian ligament
- connects other end of ovary to uterus; the distal portion of gubernaculum ovary, or round lig--artery of round lig <Artery of Samson>
- cardinal ligament
- represents 90% of ligamentous support; NOT part of peritoneum