Perineum Flashcards
perineum: description
diamond shaped space inferior to pelvic floor
pelvic diaphragm (levator ani & coccygeus muscles)
funnel shaped with anal aperture at inferior apex
perineum margin and division
anterior: inferior aspect of pubic symphysis
posterior: tip of coccyx
lateral: ischial tuberosity; ischiopubic rami, sacrotuberous lig.
ceiling: pelvic diaphragm
perineum is divided by an imaginary line between ischial tuberosities
urogentital triangles: posterior
anal triangle: posterior
urogenital triangle
laterally: ischiopubic rami
posterior: line between ischial tuberosity
anteriorly: pubic symphysis
roof: pelvic diaphragm
composed of
urogential hiatus
perineal membrane
deep perineal pouch (between levator ani and perineal membrane)
role: provide support to external genitalia & pelvic vsicera
urogenital hiatus
u shaped opening in levator ani
anal triangle
lateral: sacrtuberous ligament anteriorly : ischial tuberosity posteriorly: coccyx roof: pelvic diaphragm opening in levator ani: anal aperture external anal sphincter suround the anal canal split down the middle: ischio anal fossa
ischio-anl fossae
paired wedge-shaped spaces on either side of anal canal
space filled of adipose tissue
superiorly: pelvic diaphragm
laterally: ischium & sacrotuberous ligament
inferiorly: skin of anal region
allows movement of pelvic diaphragm
expansion of anal canal during defecation
passage of internal pudendal vessels, pudendal nerve and associate
anterior recess of ischio- anal fossae
when ischio-anal fossa project forward in urogenital triangle
superomedial wall: levator ani
lateral wall: obturator internus
floor: deep perineal pouch and perineal membrane
internal pudendal artery
from anterior trunk of internal iliac
leaves pelvic cavity through greater sciatic foramen, inf to piriformis
passes lateral to ischial spine
reach perineum through lesser sciatic
enter pudendal canal (alcock’s) formed by obturator internus muscle fascia
supplies erectile tissue, perineum, inf. rectum
gives inferior rectal artery
artery of bulb of penis/ vestibular bulb
dorsal artery of penis/clitoris
deep penile artery/ clitoris
perineal artery
internal pudendal vein
same path but reversed
pelvic veins follow course of arteries
drain perineum but not deep dorsal vein of the penis/clitoris
gives inferior rectal, vein of bulb of penis/ vestibular bulb
perineal vein
pudendal nerve
motor and sensory
leaves pelvic cavity through greater sciatic
inf to piriformis
pass through sacrospinous ligament, loop over ischial spine
through lesser sciatic foramen to reach perineum
enters perineum through pudendal canal (alcock) with internal pudendal vessels
somatic innervation of perineal and associate
gives :
inferior rectal, perineal nerve
dorsal nerve of penis/ clitoris
inferior rectal:
sensory to anal region, motor to external anal sphincter
perineal nerve
enter urogenital triangle
sensory of perineum
motor to muscle of external genitalia
dorsal nerve of penis/clitoris
enters anterior recess
sensoty to penis/clitoris
