Perineum Flashcards
Borders of anal triangle
Ischial tuberosities
Coccyx
Borders of Urogenital triangle
Ischail tuberosities
Pubic symphysis
Columns
longitudinal ridges in anal canal
Pectinate line
indicates where anal columns end
divides the origin of nerves and vessels
former site of cloacal membrane
Cloacal membrane
membrane present at pectinate line during development
Origin of NAV above pectinate line
A: inf mesenteric
N: visceral motor (parasym, sym), sensory
V: portal sys
Origin of NAV below pectinate line
A: int iliac
N: somatic motor and sensory
V: caval sys
Line connecting what landmarks divides pelvic outlet into UG and anal triangles?
Ischial tuberosities
Contents of superficial perineal pouch in both males and females
Ischiocavernosus
Bulbospongiosus
Superficial transverse perineal muscles
Deep perineal branches of int pudendal vessels and pudendal nerves
Ischiocavernosus male vs female
Male and female – split
Bulbospongiosus male vs female
Male: fused at center
Female: split
Location of superficial transverse perineal muscle
along line dividing UG and anal triangles
Midpoint of superficial transverse perineal muscle
perineal body
Spongy erectile tissue covered by ischiocavernosus in male and female
Corpus cavernosum (of penis/clitoris)
Spongy erectile tissue covered by bulbospongiosum in male and female
Corpus spongiosum (single structure in males, paired in females)
Deep perineal pouch contents
Ext urethral sphincter
Compressor urethrae *small in males – part of ext urethral sphincter)
Deep transverse perineal muscle (skeletal in males, smooth in females)
Membranous urethra (males)
What structure is the floor of the perineal pouch?
Roof?
Floor: Levator ani
Roof: perineal membrane
Innervation of anal triangle
pudendal nerve (back of pelvis) Inf anal splits off pudendal --> inf rectal runs through pudendal canal --> perineal nerve when exits canal --> splits into dorssal nerve of penis/clitoris and post scrotal/labia majora
Blood supply of anal triangle
Int pudendal a
Inf anal splits off
int pudendal becomes perineal –> branches to ext genitalia
Spongy tissue in male perineum
Corpora cavernosum (paired) Corpus spongiosum (singular, contains spongy urethra)
What spongy erectile tissue in male ends?
Which extends out to glans penis?
Ends: corpora cavernosum
Extends to glans: spongiosum
Arterial supply of male perineum
Dorsal aa of penis (paired)
Deep aa of penis (paired, in corpora cavernosa)
Both sets of aa are branches from int pudendal a
Venous supply of male perineum
One dorsal v of penis
Drains to prostatic venous plexus
Innervation of male perineum
Sym: Pudendal –> perineal –> post scrotal and dorsal n of penis
Parasum: pelvic splanchnic nerves –> form cavernous nerve plexus
Pudendal n – parasym or sym?
Sym (motor and sensory)
Cavernous nerves cause…in males
vasodilation of aa in spongy erectile tissue
Cavernous nerves originate from…
prostatic plexus (from pelvic sphlanchnic)
Innervation of female perineum
Post labial n (from perineal n, from pudendal n)
Dorsal n of clitoris (from pudendal)
Blood supply of female perineum
Post labial aa (from perineal a, from int pudendal a)
Dorsal a of clitoris (from int pudendal)
