Pelvic Vasculature and Perineum Flashcards
Internal Iliac Artery (branch off what, enters true pelvis to supply what, divides into what)
branch of common iliac artery
enters true pelvis to supple pelvic viscera, pelvic walls, perineum, and gluteal region
divides into anterior and posterior divisons
Posterior Division of Internal Iliac Artery (branches to what and name them)
branches to pelvic wall, lumbar region, and buttock
Iliolumbar Artery
Lateral Sacral Artery
Superior Gluteal Artery
Iliolumbar Artery ( supplies what)
sends branches to iliac fossa and lower lumbar region
Lateral Sacral Artery (course, supplies what)
descends anterior to sacrum
sends branches into the anterior sacral foramina to supply radicular branches to anterior spinal artery
Superior Gluteal Artery (course, supplies what)
Passes posteriorly b/w lumbosacral trunk (anterior rami or L4,L5) and anterior ramus of S1
exits pelvis via greater sciatic foramen (superior to piriformis muscle) to supply gluteal muscles
Anterior Division of Internal Iliac Artery (branches to what and name them)
supplies pelvic viscera, gluteal region, and thigh Obturator Artery Umbilical Artery Inferior Vesical Artery Middle Rectal Artery Vaginal Artery Uterine Artery Inferior Gluteal Artery Internal Pudendal Artery
Obturator Artery (course)
passes w/ obturator nerve on lateral wall of pelvis, then through obturator foramen to supply medial thigh
In 25% of people obturator artery comes from where and when is this an issue
inferior epigastric artery
can be an issue when repairing inguinal hernia
Umbilical Artery (what does it give off and supply)
patent proximal part gives off 2-3 superior vesicle arteries- supply upper part of bladder
Obliterated part of umbilical artery (what does it become)
forms medial umbilical ligament (fold)
superior vesicle arteries
branches of umbilical artery and supply upper part of bladder
Inferior Vesicle Artery (what does it supply, what is special about it)
supplies base (posterior wall) of urinary bladder, prostate, and seminal vesicles only found in males
Middle Rectal Artery (course, in males can come from what artery)
passes medially to lower rectum, prostate, and seminal vesicle may arise from inferior vesicle artery in males often absent (especially females)
Vaginal Artery (course)
passes to sides of vagina
Uterine Artery (course, issue with course)
crosses superior to ureter to enter broad ligament of uterus
problem in hysterectomy because wanna cut artery not ureter
Inferior Gluteal Artery (course)
passes posteriorly b/w anterior rami of S1 and S2 or S2 and S3
leaves pelvis by passing b/w performs muscle and coccyges muscles (artery inferior to piriformis)
passes through greater sciatic foramen to supply gluteal region
Internal Pudendal Artery (course)
first passes b/w piriformis and coccygeus muscles and leaves pelvis via greater sciatic foramen to enter gluteal region
courses inferiorly, posterior to ischial spine and sacrospinous ligament and then passes through lesser sciatic foramen to enter the perineum
Internal Pudendal Artery (supply)
main blood supply to structures of perineum
Why does the internal pudendal artery leave true pelvis via greater sciatic foramen and reenter via the lesser sciatic foramen
pelvis diaphragm supports viscera and if artery penetrated it there would be a site of potential weakness and result in herniation of pelvic viscera into perineum
perineum (what is it)
diamond-shaped region of true pelvis inferior to pelvic diaphragm
Perineum (anterior to posterior boundaries)
pubic symphysis to tip of coccyx
Perineum (lateral boundaries)
pubic arches
ischial rami
ischial tuberosities
sacrotuberous ligament
the perineum is subdivided by an imaginary line passing though ischial tuberosities creating what?
two triangular regions:
urogenital triangle
anal triangle
urogenital triangle (what is it, contents)
anterior triangle of perineum
contains urogenital structures- root of penis (male), vulva (external gentialia of female), urogenital diaphragm
Anal triangle (what is it, contents)
posterior triangle of perineum
contains- anal canal and adjacent external anal sphincter as well as ischiorectal fossa
urogenital diaphragm (where is it)
located inferior to urogenital gap in pelvic diaphragm
part of urogenital triangle
anal triangle (borders)
posterior: tip of coccyx
lateral: sacrotuberous ligament
anterior: imaginary transverse line through ischial tuberosities
ischiorectal fossa (borders)
base of wedge: located superficially at skin surrounding anus
lateral side of wedge: obturator internus muscle
medial side of wedge: pelvic diaphragm and anal canal
ischiorectal (ischioanal) fossa (what is it, what does it contain)
wedge-shaped
fat filled- supports anal canal
contains- pudendal nerve and internal pudendal artery and vein (coursing anteriorly and inferiorly along lateral wall)
anterior recess of ischiorectal fossa is where
b/w pelvic diaphragm and urogenital diaphragm in urogential triangle
what supports the anal canal, allowing for distention during dedication
ischiorectal fossa
Pudendal Canal (Alcock's canal) (what is it, what does it contain)
fascial canal within obturator internus fascia on lateral wall of ischiorectal fossa
contains pudendal neurovascular bundle
extends from lesser sciatic foramen (posteriorly) to urogenital diaphragm (anteriorly)
Pudendal Nerve (formed from what)
anterior rami of S2-4 of sacral plexus
Pudendal Nerve (what type of nerve is it)
somatic (voluntary) nerve
somatic innervation to most of perineum
Pudendal Nerve (course)
passes out of main pelvic cavity via inferior part of greater sciatic foramen to enter gluteal region
descends posterior to ischial spine
passes through lesser sciatic foramen to enter pudendal canal
Pudendal Nerve (branches)
branching occurs in anal triangle:
Inferior rectal nerve
branches to structures of urogenital triangle (dorsal nerve of penis/clitoris and posterior scrotal/labial nerves)
Internal Pudendal Artery (branches)
Inferior rectal artery
branches to structures of urogenital triangle (dorsal branches to penis and clitoris)
how does lower half of anal canal get blood supply
inferior rectal artery (branch off internal pudendal, which is branch of internal iliac)
Anal Canal (course)
terminal part of large intestines
begins at narrowing of rectal ampulla at level of pubertal sling of pelvic diaphragm
bent at angle at anorectal junction
descends posteroinferiorly to anus b/w anococcygeal body and perineal body
what is landmark for beginning of anal canal
coccyx
Internal Anal Sphincter (what is it, innervation)
thickening of smooth circular muscle of upper part of anal canal wall
involuntary- parasympathetic
parasympathetic stimulation of the internal anal sphincter does what
relaxes sphincter
external anal sphincter (what is it, innervation)
striated muscle surrounding lower part of anal canal
extends from perineal body to anococcygeal body
voluntary- inferior rectal nerve
Name the parts of the external anal sphincter
Deep part
Superficial part
Subcutaneous part
Deep Part of External Anal Sphincter (what does it do)
fuses with adjacent puborectalis muscle of pelvic diaphragm
Superficial Part of External Anal Sphincter (what does it do)
moors anal canal in median place by its attachments to perineal body and anococcygeal body
Subcutaneous Part of External Anal Sphincter (what does it do)
slender
surrounds anus
external anal sphincter (action)
closes anal canal
whats responsible for the bend at anorectal junction
puborectalis
Puborectalis aids closure of anorectal junction how
drawing posterior wall of anal canal anteriorly, keeping posterior wall of anorectal junction opposed to anterior wall except during defecation
Anorectal ring (what is it, what is it composed of)
palpable landmark during rectal exam
composed of depp part of external anal sphincter, puborectalis, and internal anal sphincter
anorectal ring determines what about a patient
continence
Anal Columns (what are they, what do they contain)
characteristic vertical folds of mucus membrane
contain superior rectal vessels
location of portal-caval anastomosis
anal columns
anal valves (what are they)
semilunar epithelial folds joining inferior ends of anal columns
what structures indicate the pectinate line
anal valves
what does the pectinate line mark
juncture between hindgut endoderm and ectoderm of proctodeum
location of embryonic anal membrane (former cloacal membrane)
anal valves
anal sinuses (what are they)
recesses superior to anal valve and between anal columns
upper half of anal canal gets blood from where
superior rectal artery and vein from inferior mesenteric artery and vein
upper half of anal canal drains lymph through where
inferior mesenteric nodes
upper half of anal canal is innervated by what
stretch receptors and other visceral afferents send sensory fibers into hypogastric plexus of autonomic system
no somatic sensory fibers so area not so sensitive
lower half of anal canal is innervated by what (what does it respond to)
somatic sensory fibers from inferior rectal nerve (branch of pudendal nerve)
respond to pain, touch, and temp
very sensitive
lower half of anal canal is gets blood supply by what
inferior rectal artery
lower half of anal canal drains lymph through what
medial nodes of superficial inguinal lymph nodes (inferior to inguinal ligament)
what can be torn by hard stools in a chronically constipated patient, tearing anal mucosa
anal valves
tearing of anal valves can cause what
anal canal to be infected and from fistula through wall of anal canal into the ischiorectal fossa- can result in perianal abscess
perianal abscess (what is it)
collection of pus in fat in ischiorectal fossa
Perianal Abscess (how can it spread)
from one side to the opposite sid
anteriorly into anterior recess of ischiorectal fossa (b/w elevator ani and urogenital diaphragm) to affect urogenital structures
Internal Hemorrhoids (what are they)
varicosities of tributaries of superior rectal veins in anal columns covered by mucous membrane of anal columns
External Hemorrhoids (what are they)
varicosities of tributaries of interior rectal veins covered by skin (very painful- somatic fibers of inferior rectal nerve)
Urogenital Triangle (location)
anterior part of perineum
below part of pelvic diaphragm which has a central urogenital gap