Week 6: Pelvis and Perineum Flashcards
pelvic inlet
- circular opening where the abdominal cavity is continuous with the pelvic cavity
- sacral promontory protrudes into this opening
pelvic outlet
diamond shaped and bounded by the pubic symphysis, pubic arches, inferior pubic rami, ischial rami, sacrotuberous ligament, and the coccyx
sciatic notch
between posterior inferior iliac spine and the ischial spine
sacrospinous ligament
changes the sciatic notch into an opening, the greater sciatic foramen
difference between male and female for pelvic inlet
female: wide, oval or circular
male: narrow, heart-shaped
difference between male and female for sacrum
female: short, straight
male: long, prominent
difference between male and female for coccyx
female: straighter
male: curves ventrally
difference between male and female for sciatic notch
female: wide
male: narrow
difference between male and female for subpubic angle
female: broad, rounded (80-85 degrees)
male: deep, acute (50-60 degrees)
pelvic wall muscles
piriformis and obturator internus
pelvic floor consists of
pelvic diaphragm and urogenital diaphragm
pelvic diaphragm
- levator ani and coccygeus muscles
* thin sheets of muscles that the urethra, vagina, and rectum pass through
levator ani
made up of iliococcygeus, pubococcygeus, and puborectalis
illiococcygeus and pubococcygeus contract when
abdominal pressure is raised to support the pelvic organs
pubococcygeus helps
maintain urinary and fecal continence
puborectalis function
relaxes and contracts the anorectal angle to control defacation and aids in voluntary control of micturition
coccygeus
- deep to sacrospinous ligament
* pulls the coccyx forward after defacation
uterus
pear-shaped and has 4 regions: fundus, body, isthmus, and cervix
fundus of uterus
the upper area in which the uterine tube connect to the uterus
body of uterus
starts below the level of uterine tubes and continues downward until the uterine walls and cavity begin to narrow
isthmus of uterus
the lower, narrow, neck region
cervix
extend from isthmus until it opens into the vagina
anteverted or anteflexed uterus
- normal position of uterus
* oriented anteriorly toward the bladder
retroverted or retroflexed uterus
- a normal anatomical variation of uterus position (1 in 4)
* oriented posteriorly toward the rectum
flexion of uterus
the angle between the uterine body and isthmus
version of uterus
the angle between the cervical canal and the vagina
broad ligament
- formed by the double layer peritoneum (mesentery) that drapes over the female reproductive tract
- can be divided into parts depending on what structure it covers; vessels, nerves, and lymphatics travel via these messenteries
mesometrium
the mesentery of the uterus; it is adjacent to uterus
mesovarium
mesentery of the ovary
mesosalpinx
mesentery of the uterine tube (also called salpinx)
what passes through the suspensory ligament of the ovary
ovarian vessels from the aorta to the ovary
ovarian ligament
attaches the inferomedial pole of the ovary to the uterus
round ligament of the uterus
is continuous with the ovarian ligament and travels from uterus laterally to enter the deep inguinal ring
vesicouterine pouch
recess between bladder and uterus
rectouterine pouch (of Douglas)
recess between the uterus and rectum
pubovesical ligaments
- formed by pelvic fascia deep to the peritoneum that thickens to help support pelvic organs
- from pubic bones to bladder
transverse cervical ligaments
- formed by pelvic fascia deep to the peritoneum that thickens to help support pelvic organs
- (cardinal ligaments) from uterus to lateral pelvic wall
uterosacral ligaments
- formed by pelvic fascia deep to the peritoneum that thickens to help support pelvic organs
- from uterus to sacrum
damage to pubovesical, transverse cervical, and uterosacral ligaments
- can be caused by multiparity, birth trauma, obesity, chronic cough, and heavy lifting
- can result in stress incontinence, bladder prolapse, or varying degrees of uterine prolapse =
what ligaments are involved in bladder prolapse
pubovesicle ligaments
what ligaments are involved in uterine prolapse
transverse cervical ligaments
testes
descend into the scrotum and are attaches to the seminal vesicle by the vas deferens
ejaculatory ducts are embedded into
the prostate
during ejaculation, semen passes
from the seminferous tubules in the testis -> the epididymis and vas deferens -> ejaculatory ducts -> urethra
epididymis is continuous with
the vas deferens
tunica vaginalis
- in descent of testes into scrotum, tunica vaginalis attaches to the anterior and lateral aspect of the testes
- it has a visceral and parietal layer
descent of testis forms
inguinal canal and spermatic cord, which is covered in layers derived from the abdominal wall
external spermatic fascia
layer of spermatic cord derived from external oblique aponeurosis
cremasteric fascia/ muscle
layer of spermatic cord derived from the intenal oblique muscle
internal spermatic fascia
layer of spermtic cord derived from transversalis fascia
spermatic cord contains
ilioinguinal nerve, genital branch of genitofemoral nerve, testicular artery, pampiniform plexus, lymphatics, and vas deferens (and deferential vessels)
inguinal canal
- an oblique passageway through the abdominal wall
- begins at the deep inguinal ring, passes obliquely toward the midline under the transverse abdominal and internal oblique muscles, and ends at the superficial inguinal ring
deep inguinal ring
- in transversalis fascia
* is the beginning of the inguinal canal
superficial inguinal ring
- opening in the aponeurosis of the external oblique musle
* is the end of the inguinal canal
what is contained in the inguinal canal
in males: spermatic cord
in females: round ligament of uterus
blood supply of reproductive system
from the internal iliac artery, a branch of the common iliac artery
internal iliac branches common to males and females
iliolumbar, lateral sacral, superior gluteal, inferior gluteal, internal pudendal (gives off inferior rectal branch), umbilical - (superior) vesicle arteries to the bladder, obturator, middle rectal
female exclusive branches off the internal iliac
uterine and vaginal arteries
male exclusive branches off the internal iliac
deferential artery (a branch of the umbilical artery to the vas deferens)
superficial and deep inguinal nodes
- receive lymph from the perineum and lower limb
* drains to external iliac nodes, then common iliac, finally lateral aortic nodes
lymph from ovaries and testies
flow directly to the lateral aortic nodes because they are supplied from branches that come directly off the aorta
lymph from lateral aortic nodes drain to
cisterna chyli and then thoracic duct
Body of bladder
- main portion
* collects urine
neck of bladder
- funnel shaped extension
* connects bladder to the urethra
bladder lined with
transitional epithelium
detrusor muscle
- 3 poorly defined layers of smooth muscle in the bladder
* the bulk of the bladder wall
internal urethral sphincter
- below the neck of the bladder
* consists of smooth muscle cells extending from the detrusor muscle
external urethral sphincter
- at the level of the pelvic floor (below internal urethral sphincter)
- composed of voluntary striated muscle fibers
micturition reflex
- autonomic regulation of micturition by spinal cord reflex
- involves impulses traveling from bladder to sacral spinal cord and vice versa
- can be inhibited or facilitated by neurons located in cerebral cortex or brainstem
micturition occurs in 2 phases
- filling phase and emptying (voiding) phase
* both require coordinated interaction between bladder and nervous system
bladder filling is parasympathetic or sympathetic
sympathetic
sympathetic=stores
bladder emptying is parasympathetic or sympathetic
parasympathetic
perineum
- diamond shaped area below pelvic floor
* divided into 2 triangles by drawing a line between ischial tiberosities
anterior urogenital triangle
associated with openings of urinary and reproductive systems and functions to anchor the external genitalia
posterior anal triangle
contains the anus and the external anal sphincter
nerve and blood supply to perineum
pudendal nerve (S2-S4) and internal pudendal artery
deep perineal pouch
- part of urogenital triangle
- potential space between pelvic diaphragm and perineal membrane
- contains part of urethra, external urethral sphincter, and deep transverse perineal muscle (also bulbourethral glands in males and part of the vagina, compressor urethrae, and sphincter urethrovaginalis in females)
perineal membrane
tough fascia that provides attachment for external genitalia and helps support the pelvic organs
superficial perineal pouch
- part of urogenital triangle
- potential space between perineal membrane and perineal fascia
- contains external genitalia
perineal body
- connective tissue structure (central tendon) into which pelvic floor and perineal muscles attach
- in the midline of the perineum
erectile tissue of males
copora cavernosa and corpus spongiosum compose the penis
erectile tissue of females
- vestibular bulbs (bulb of the vestibule) - deep to labia majora and separated by vaginal opening
- crura of clitoris - join to form the body and glans of clitoris
bulbospongiosum
- covers proximal end of corpus spongiosum (bulb of penis) in males
- covers vestibular bulbs in female
Thin skeletal muscles that cover proximal ends or roots of erectile tissues
- bulbospongiosum, ischiocavernosum, and superficial transverse perineal muscles
- contract to move blood volume during orgasm
ischiocavernosum
- covers proximal end of corpora cavernosa (crus of penis) in males
- covers crus of the clitoris in female
- lies along the pubic ramus on each side
superficial transverse perineal muscle
runs transversely across the posterior border of the urogenital triangle from the ischial tuberosity to insert in the perineal body, along with the bulbospongiosum and external anal sphincter
