Pelvis Perineum Anatomy (ketchum) 1 and 2 Flashcards
what are the three bones of the pelvis
ileum
ischium
pubis
what are the parts of the ilium?
what does the ilium articulate with?
ala (wing)
body–> participates in formation of the upper 2/5th of the acetabulum
articulates with the sacrum posteriorly
what portion of the acetabulum does the ischium contribute
the body forms the posterior-inferior 2/5th of the acetabulum
what portion of the pubis contributes to the acetabulum and how much of the acetabulum is pubis making up?
superior ramus forms the anterior 1/5th of the acetabulum
what is the pubic symphysis
fibrocartilaginous disc linking two pubis bones
thicker in females and responsive to hormonal changes during pregnancy
only site of movement of the pelvis during pregnancy
what type of joint is the sacroiliac joint and what type of motion occurs here
synovial joint b/w sacrum and ilium
gliding motion (primarily)
can be rotatory
what ligaments reinforce the sacroiliac joint
anterior and posterior and interosseous sacroiliac ligaments
sacrotuberous ligament (sacrum to ischial tuberosity)
sacrospinous (ischeal spine to the sacrum)
what ligaments prevent rotatory movement of the sacroiliac joint
interosseous sacroiliac and sacrotuberous ligaments
what type of joint is the lumbosacral joint
fibrocartilaginous between L5 and S1
where does the iliolumbar ligament attach
from transverse process of LV5 to iliac crest
what is the terminal line
a line along the pubic and iliac bones to the base/pelvic surface of sacrum
aka the pelvic inlet
divides the pelvis into two portions
1) major (false) pelvis above the line
2) minor (true) pelvis below the line
what is the pelvic outlet
the line from the tip of the coccyx to the lower boundary of the pubic symphysis
what is the normal erect position? at what angle is the pelvis sitting
pelvis normally tips at 50-60 degrees from the horizontal
base of the sacrum is 4” higher than the symphysis
ASIS and the symphysis lie in roughly the same vertical plane!!
how is the female pelvis different than the male pelvis? major pelvis iliac crests minor pelvis sacrum subpubic angle
shallower major and minor pelvis iliac crests (anterior) are more everted
shallower, wider minor pelvis
relatively greater diameters
broader, less concave sacrum
pelvic inlet wider & more oval
subpubic angle greater
what are the four types of pelves
android
anthropoid
gynecoid
platypelloid
android pelvis
most common male pelvis (30 percent of females)
heart shaped pelvic inlet
anthropoid pelvis
2nd most common male pelvis (20 percent females)
exaggerated anterior and posterior inlet
gynecoid pelvis
most common female pelvis (47 percent of females)
slightly oval-shaped pelvic inlet
platypelloid pelvis
least common in both sexes (~3% of female pelves)
exaggerated transverse inlet diameter
what are the pelvic diameters of the superior aperture
true congugate
diagonal conjugate
transverse
oblique
what are the pelvic diameters of the inferior aperture
transverse
anterior sagittal
posterior sagittal
true conjugate
sacral promontory to pubic symphysis (upper border)
can measure by palpation (OB)
diagonal conjugate
from the sacrovertebral angle to the inferior margin of the symphysis
transverse diameter of the superior aperture? inferior aperture?
superior–> greatest width (horizontal) of superior aperture
inferior–> b/w the inner surfaces of the ischial tuberosity
oblique diameter of the superior aperture
from the sacroiliac articulation of one side to the iliopectineal eminence of the other side
anterior and posterior sagittal diameters of the inferior aperture
anterior -> from transverse diameter to the symphysis
posterior–> from the transverse diameter to the sacrococcygeal junction
anything beneath the pelvic diaphragm is considered what….
perineum
what is the genital hiatus
where the urethra and vagina (or male counterparts) pass through the pelvic diaphragm
what is the urogenital diaphragm
a second diaphragm that is in the perineum that supports midline structures such as urethra, vagina, prostate
it is a voluntary muscular sheet between the ischiopubic rami
attachments of the obturator internus
where does it exit the pelvis
origin
obturator membrane
rim of obturator foramen
insertion
greater trochanter of femur
leaves the pelvis as a tendon thru the lesser sciatic notch
action of obturator internus
external rotation of thigh
innervation of the obturator internus
nerve to obturator internus
attachments of the piriformis
where does it exit the pelvis
origin–> sacrum
insertion–> greater trochanter of femur
exits pelvis through greater sciatic foramen
2 actions of the piriformis
external rotation of the thigh
abduction of the thigh
innervation of the piriformis
ventral rami of S1 and S2
what muscles make up the inner walls of the minor pelvis
obturator internus
piriformis
what muscles make up the pelvic diaphragm
levator ani (pubococcygeus, iliococcygeus, puborectalis)
coccygeus
what innervates the levator ani muscles
perineal branches of S3 and S4
what are the attachments of the iliococcygeus muscle
origin:
arcus tendineus obturator fascia
insertion:
coccyx
anococcygeal lig.
what is the action of the iliococcygeus muscle
support pelvis viscera
what are the attachments of the pubococcygeus muscle
origin: pubis
insertion:
coccyx
anococcygeal lig.
what is the action of the pubococcygeus
support pelvic viscera
what are the attachments of the puborectalis
origin–> pubis
insertion–> puborectalis muscle (attaches onto itself
what is the action of the puborectalis
support pelvic viscera
maintain anorectal junction
what are the attachments of the coccygeus
origin–> ischial spine and sacrotuberous ligament
insertion–> coccyx and lower part of sacrum
what is the action of the coccygeus
support pelvic viscera (it is the most posterior muscle of the pelvic diaphragm)
what are the urinary tract elements in the pelvis
pelvic portion of ureter
urinary bladder
what are the gastro-intestinal tract elements of the pelvis
rectum and anal canal
what are the female and male reproductive organs in the pelvis
F–> vagina, uterus, uterine tubes, ovaries
M–> pelvic portion of vas deferens
seminal vesicles
prostate gland
what is endopelvic fascia
lining of the pelvic walls and floor
this lining consists of membranous lining and loose CT
covers and surrounds pelvic contents
fills space b/w peritoneum and muscles
pelvic peritoneum
does NOT contact floor and walls of pelvis
it is draped over superior aspects of pelvic structures
forms distinctive folds and pouches
what are the pouches made by peritoneum in the female
what is the significance of these pouches
rectouterine pouch–> b/w rectum and uterus
vesicouterine pouch–> b/w superior aspect of the urinary bladder and uterus
these are areas where material might collect/build up
also locations of ectopic pregnancy
what pouch does peritoneum form in the male
rectovesical pouch b/w bladder and rectum
what is the broad ligament
found only in females
reaches laterally across the pelvis and is folded over the uterus
formed during formation of uterus and vagina from paramesonephric ducts
what is the perineum
diamond shaped area between the coccyx and the pubis
often referred to as the centrol (perineal body)
what are the boundaries of the perineum
anterior - pubis, ischiopubic rami
posterior - ischial tuberosities, sacrotuberous ligaments, & coccyx
superior - separated from pelvic cavity by pelvic diaphragm
inferior – skin surface (posteriorly), superficial fascia (anteriorly)
what is the perineum divided into
anal triangle and urogenital triangle (line connecting ischial tuberosities)
what are the boundaries of the anal triangle
anterior - posterior edge of urogenital triangle
posterior - boundaries of perineum
lateral - ischiopubic rami and obturator internus m. below the arcus tendineus
superior - the roof of the anal triangle is formed by the inferior aspect of the pelvic diaphragm
inferior- skin and superficial fascia of perineum
what are the boundaries of the ischioanal fossa
superior - levator ani and pelvic diaphragm
inferior - skin of the perineum
posteiror- posteriorly the right and left ischioanal fossa communicate
anterior - components of the external anal sphincter and UG diaphragm fuse
anterior recesses- extend anteriorly between the levator ani and urogenital diaphragm
what muscles are in the urogenital diaphragm
shincter urethrae muscle which surrounds the urethra (in the female this is called the urethrovaginalis b/c it also surrounds the vagina)
compressor urethrae
-this extends laterally from the sphincter
deep transverse perineal muscle
what membrane covers the UG diaphragm more externally?
perineal membrane
what fascia layer covers the perineal membrane
colle’s fascia
what is the ligament that is an anterior thickening of the perineal membrane
what is the significance of this ligament
trasnverse perineal ligament
this is the stopping point of the perineal membrane so that is does not extend to the pubis
allows passage of the deep dorsal vein of penis (or clitoris) to enter pelvis
where is the superior fascia of the UG diaphragm derived
transversalis fascia
what components are in the superficial perineal space ?
erectile bodies
musculature
vessels
nerves
what components are in the deep perineal space (between the inferior and superior fascia of UG diaphragm)
muscles of UG diaphragm
Vessels and nerves
moving externally to internal what are the layers you hit in the perineum area….
skin superficial fascia (campers then colle's (scarpa's) fascia)
superficial perineal space perineal membrane deep perineal space superior fascia of UG diaphragm ischioanal fossa pelvic diaphragm (levator ani muscles) extraperitoneal CT peritoneum peritoneal space in pelvis
see last slide in the pelvis perineum 1 powerpoint
where does the bladder sit
behind the pubic symphysis
what are the 4 surfaces of the bladder
superior
inferolateral (two)
inferoposterior - base of bladder
what is the apex of the bladder and what arises there
junction of inferolateral and superior surfaces
median umbilical ligament (urachus) arises here
where do ureters enter the bladder
superior -lateral angles
what is the neck of the bladder
junction of inferolateral and inferoposterior surfaces
which surrounds urethral opening
what space separates the bladder from the pubic rami
prevescial fascial space
what sits posterior to the bladder in the male
rectum
ductus deferens
seminal vesicles
what sits posterior to the bladder in females
cervix and upper vagina
what is the muscular wall of the bladder and what is it innervated by
“detrusor” innervated by parasympathetics
what is the mucous membrane of the bladder
transitional epithelium
what is the trigone of the bladder
area between the orifices of the ureters superiorly and internal urethral orifice inferiorly
what innervates the trigone
sympathetics–> prevents retrograde urine flow
what are the three vessels that innervate the bladder
superior vesicle (from umbilical) (major)
middle vesicle (from superior vescial)
inferior vesical (from anterior division of internal iliac artery) -vaginal artery in
what is the venous drainage of the bladder like
Does NOT follow arteries
drains into dense venous plexus around base & neck
prostatic plexus of the male
vesico-vaginal plexus of the female
drains with deep dorsal v. of penis to internal iliac v.
this probably means that metastatic cancer in the prostate will spread easily to bladder area
where does the pelvic ureter enter the pelvis (by crossing what structures?)
enters the pelvis by crossing iliac vessels anteriorly
what crosses anterior to the ureter in males
ductus deferens
what crosses anterior/superior to the ureter in females
uterine artery
what is the significance of the ureters staying in the wall of the bladder for about 2 cm before opening at the ureteral orifices …
since ureters have no valves this path creates a means of preventing backflow of urine
contraction of bladder closes the ureters during urination
compression of ureter by distended bladder
what is the vascular supply to the ureters
common iliac
internal iliac
vasiculodefernetial (male)
uterine (or inferior vesical artery) (female)
venous supply follows arteries
what are the 4 parts of the male urethra
intramural–> wall of bladder
prostatic –> from internal urethral orifice through prostate gland (1 inch)
membranous–> through urogenital diaphragm , surrounded by sphincter urethrae m.
penile (Spongy) –> from inferior surface of urogenital diaphragm through spongy body of penis
what are the two lumiinal dilations of the male urethra
within the bulb (bulbar portion)
within the glans penis (fossa navicularis)
what are the two glands that open into the penile urethra
bulbourethral (Cowper’s) glands
opens into bulbar portion
urethral glands (of Littre)
numerous small glands
in proximal 2/3 of spongy body
what are the two parts of the female urethra
superior portion
surrounded by urethral glands
paraurethral glands correspond to prostate in male
homolog is the prostate glands
membranous
pierces urogenital diaphragm
what is the rectum? at what level of vertebrae does it originate
terminal 6-8 inches of large bowel
originates at level of 3rd sacral vertebrae (rectosigmoid junction)
what morphological features distinguish the rectum from sigmoid colon
rectum has no mesocolon and is therefore retroperitoneal
teniae coli spread out as longitudinal m surrounding entire rectum
what is the rectum proper
from origin to perineal flexure
dilated caudal portion is the ampulla
what is the anal canal
perineal flexure to anus
anatomical and clnical anal canal differ
what is the anatomical anal canal and what is the clnical anal canal
anatomical–> from level of upper surface of pelvic diaphragm to anus 1- 1.5 inches long
clinical –> from pectinate line to anal verge (1/2 inch long)
what part of the rectum contacts the peritoneum
ventral rectum
what structures are palpable on exam in a rectal exam of the male
contents of rectovesical pouch posterior surface of bladder seminal vesicles distal vas deferens prostate sacrum, coccyx, ischial spines
what structures are palpable on exam in rectal of female
contents of rectouterine pouch
cervix
vagina
sacrum, coccyx ischial spines
what are the muscular/tissue layers of the rectum
outer longitudinal–> blends with fibers of levator ahi at anal region
inner circular muscle–> thickened to form internal anal sphincter
submucosal layer –> loose connective tissue
mucosal layer
what are plica transversales
transverse rectal folds
these are semilunar folds of mucosa, sucmucosa and cirucular muscle
three folds typically
2 from left
1 from right
lowest is 2 inches above anus
highest is at the rectosigmoid junction
what are rectal columns
mucous membrane overlying submucosal arteries and veins
what are anal valves
archlike folds of mcuous membrane connecting caudal ends of rectal columns
these cover the anal sinues
what is the pectinate line
irregular circumferential line formed by anal valves and base of rectal columns
dividing line (with variation) for….
1) venous drainage
superior–> drains to middle an superior rectal
inferior –> inferior rectal v
2) lymphatic drainage
superior–> drains to pelvic nodes
inferior –> inguinal nodes
3) Nerve supply
superior –> autonomics
inferior–> somatic
4) Epithelial lining
superior–> typical GI tract mucous lining
inferior –> stratified squamous epithelium
what is the pecten
area immediately below pectinate line
characterized by great amount of CT creating blue-white appearance
what is the anal verge
caudal most portion of anal canal
skin picks up sweat glands and hairs
what are the three major arterial suppliers to the rectum
superior rectal - from inferior mesenteric
- near rectosigmoid junction it divides into right and left branches
- does NOT supply upper 1/5 to 1/4 of rectum
middle rectal - variable in origin (from internal iliac or other pelvic artery)
-middle of rectum
inferior rectal- from internal pudendal
-supplies external anal sphincter and perianal portion of levator ani muscle
what is the venous drainage of the rectum
to two intercommunicating plexus
submucosal (subcutaneous plexus)
-within submucosa immediatley under skin of anal canal
superior rectal above pectinate line
inferior rectal below pectinate line
perimuscular plexus
- drains muscular wall of rectum below level of peritoneum
- mostly drains into middle rectal vein
where does most of the blood supply to the pelvis originate
internal iliac
where does the internal iliac divide and into what?
divides at the upper border of piriformis and divides into anterior and posterior trunks
anterior–> arises lateral to the pelvic plexus
what are the 3 branches off the posterior trunk of internal iliac
iliolumbar
lateral sacral
superior gluteal
what does the iliolumbar branch into and what do these supply
lumbar branch–> supplies psoas and quadratus lumborum
iliac branch-> supplies iliacus
what does the lateral sacral artery supply
it is multiple arteries (mostly just 2)
first branch–> enters sacral foramne
-supplies–> structures of vertebral canal, skin and muscle over dorsum of sacrum
anastomoses with superior gluteal artery
second–> descends along sacrum medial to anterior foramina
where does the superior gluteal artery leave the pelvis
greater sciatic foramen above piriformis muscle
what are the 8 branches of the anterior trunk of the internal iliac artery
umbilical (superior vesicle) middle rectal inferior rectal obturator internal pudendal inferior gluteal uterine and vaginal vesiculodeferential
what are two other vessels that supply pelvis but are not branches of the internal iliac a
middle sacral–> arises from aorta along anterior surface of sacrum–> sends small communicating branches to the lateral sacral arteries
superior rectal artery–> branch of the inferior mesenteric –> distributes to posterior wall of rectum
what are the main venous drainage systems of the pelvis
internal iliac v.
iliolumbar v.
***note lots of anastomotic connections exist in the pelvis which creates multiple routes of transmission for infections and metastases
what are the cruciate anastomoses of the pelvis
gluteal artery and perforating branch of profunda femoris
what does the obturator a. communicate with
iliac branch of iliolumbar communicates with?
lumbar branch of iliolumbar?
medial femoral circumflex
deep circumflex iliac a.
lumbar branches of aorta
internal pudendal communicates with what
external pudendal a.
lateral sacral aa. communicate with…
middle sacral artery
superior rectal artery communicates with …
middle and inferior rectal arteries
what forms the lumbosacral plexus
the lumbar plexus (T12-L5)
sacral plexus (S1-S4)
what do the anterior divisions of the lumbosacral plexus supply? posterior divisions?
anterior–> original flexor muscles
posterior–> extensor muscles
where do the anterior and posterior divisions of the lumbar plexus leave the pelvis? sacral plexus?
lumbar plexus–> on anterior aspect of thigh
sacral–> leave posteirorly entering the buttocks
what 5 nerves make up the anterior division of the lumbar plexus
iliohypogastric ilioinguinal genitofemoral obturator L4 contribution to sacral plexus
what 3 nerves make up the posterior division of the lumbar plexus
lateral femoral cutaneous
femoral n
accessory obturator n.
what 4 nerves makes up the anterior portion of the sacral plexus
tibial portion of sciatic
n to quadratus femoris
n. to obturator internus
pudendal
what 5 nerves make up the posterior division of the sacral plexus
superior gluteal n. inferior gluteal n. common fibular portion of sciatic n. to piriformis posterior femoral cutaneous
