Perineum Flashcards
What is the most inferior region of the trunk?
the perineum
where is the perineum located ?
at the pelvic outlet, the inferior margin of the pelvis and spinal column
*between the buttocks and the thighs
what are the boundaries of the perineum?
pubic symphysis, ischiopubic rami, the ischial tuberosities and coccyx
a transverse line between the ischial tuberosities subdivides the diamond shaped pelvic outlet into an
anterior urogenital triangle and posterior anal triangle
what passes through the urogenital triangle
urethra and vagina
what passes through the anal triangle?
the anal canal
A sheet of skeletal muscle that closes the pelvic outlet or forms the floor of the pelvis
the pelvic diaphragm
what is the major function of the pelvic diaphragm?
to support the pelvic contents
what muscle runs from the coccyx to the ischial spine and reinforces the pelvic outlet posteriorly?
coccygeus muscle
group of muscles that make up the major portion of the pelvic diagphragm
levator ani
the levator ani is a group of muscles that can be subdivided into?
pubococcygeus, puborectalis and iliococcygeus
most important of the levator ani muscles? what does it do?
puborectalis- it creates a sling that reinforces the rectoanal flexure- this is extremely important for fecal continence
during defecation, what muscle must relax to allow the bend where the rectum joins the anal canal to relax?
puborectalis
where do the fibers of the levator ani decussate between in females and males? what do they decussate into?
in females- between the vagina and anus
in males- between the prostate gland and the anus
they decussate into a mass of fibrous tissue called the central tendon of the perineum
what is the thickest portion of the levator ani and provides main support of the pelvic floor?
central tendon of the perineum
because the pelvic diaphram does not cover the pelvic outlet completely, what space is left open?
urogenital hiatus
what passes through the urogenital hiatus in males and females
men- urethra
female- urethra and vagina
the urogenital diaphragm extends between? what does it consist of?
the two ischiopubic rami and consistes of two layers of fascia with an intermediate layer of skin
the muscular layer of the urogenital diaphragm includes?
the more anterior sphinter urethrae and the more posterior deep transverse perineus
what forms the voluntary sphincter when you relax and begin urinating
sphincter urethrae
what muscle contributes to the perineal body
the deep transverse perineus
what is the arrangement of the layers of the pelvic diaphragm from superficial to deep
muscles of the erectile tissue
UG diaphragm
Pelvic diaphragm
pelvic outlet
the web-shaped space between the pelvic diaphragm and the obturator internus muscle is the?
ischioanal or ishiorectal fossa.
in a normal specimen, what is the ishioanal specimen filled with?
fat, and the inferior rectal vessels and nerves that supply the anal sphincter, lining of the anal canal and perianal skin
what is the purpose of the fa in the ishioanal fossa?
the loos fat allows the anal canal to expand during defecation
where is ischioanal fossa located?
the ischioanal fossa extends anteriorly deep to the urogenital diaphragm on either side of the midline and extend posteriorly between the gluteus maximus muscle and pelvic diaphragm