Perineum Flashcards
what is the perineum
the region that lies below the levator ani (pelvis diaphragm) and medial to the sacrotuberous ligament
the levator ani forms the ___ of the pelvis and the ___ of the perineum
floor of the pelvis and the roof of the perineum
blood supply and innervation of the perineum
- internal pudendal artery
- pudendal nerve
the internal pudendal a. and pudendal n. leave the pelvis via what structure to briefly enter the gluteal region?
greater sciatic foramen
the internal pudendal a. and pudendal n. pass through the ______ to the enter the perineum
lesser sciatic formen
once the internal pudendal artery and pudendal n. pass through the lesser sciatic foramen, they lie on the ___ wall of the perineum and are covered by ___ ___ forming the ___ ___
lateral; deep fascia forming the pudendal canal
greater sciatic foramen location
- in front of hip bone
- behind sacrotuberous ligament
- above sacrospinous ligament
lesser sciatic foramen location
- in front of hip bone
- behind sacrotuberous ligament
- below sacrospinous ligament
the anatomical perineum is roughly what shape
diamond
boundaries of the perineum
- pubic symphysis
- left and right ischiopubic ramus
- sacrotuberous ligament
- left and right ischial tuberosities
- the coccyx
an imaginary line passing between the ischial tuberosities divides diamond shaped perineum into two triangular regions called
- the urogenital triangle anteriorly
- anal triangle posteriorly
due to the anterior tilt of the pelvis, the urogenital triangle is ____ to the floor while the anal triangle is ___ in orientation
horizontal; vertical
2 regions of the urogenital triangle
- UG diaphragm (deep pouch)
2. superficial pouch
what is the UG diaphragm
a diaphragm structure comprised of muscle, connective tissue, and neurovascular branches of the pudendal n.
what is the inferior boundary of the deep pouch (UG diaphragm)
perineal membrane; external genitalia hang off here
the superficial is located where
below the deep pouch
in the male, the UG diaphragm fills the deficit of the levator ani muscle ____ but does not extend ___
anteriorly but does not extend posteriorly
in the male what structure is related to the top of the UG diaphragm
prostate
all structures below the perineal membrane are in the ____ pouch of the urogenital triangle (external genitalia and vulva)
superficial
the anal canal is or is not in the superficial pouch
IS NOT as it is located in the anal triangle of the perineum
what structure is associated with the tip of the UG diaphragm in the female
bladder
contents of the UG diaphragm in males
- deep transverse perineal m.
- membranous urethra
- external urethral sphincter m.
- bulbourethral glands (males only)
- branches of pudendal n/a/v
contents of the UG diaphragm in females
- deep transverse perineal m.
- membranous urethra
- external urethral sphincter m.
- compressor urethra (females only)
- branches of pudendal n/a/v
muscles of the UG diaphragm are innervated by what nerve
pudendal nerve
the region inferior to the perineal membrane is the ____ ____ ____
superficial perineal membrane
structures of the superficial pouch
- crura of penis and crura of clitoris
- bulb of the penis (males)/vestibular bulbs (females)
- ischiocavernosus muscle
- bulbospongiosus muscle
- vestibular gland (female) muscles
- superficial transverse perineal muscle
what is the perineal body
a mass of connective tissue located at the midpoint of the line connecting the ischial tuberosities
the perineal body serves as the attachement point for muscles of the pelvis and the perineum, those muscles are:
- the levator ani
- deep perineal m.
- superficial perineal m.
- bulbospongiosus mm.
- external anal sphincter
tears of the perineal body may lead to what
may compromise structural integrity of the pelvis and perineum and lead to prolapse of organs and urinary incontinence
the superficial fascia of the perineum and abdomen are ____ with each other but are given regional names
continuous
what is the camper’s fascia
superficial fatty layer under skin
scarpa’s fascia
superficial fascia located in the abdominal (infraumbilical region)
dartos fascia
located in the region of the scrotum and the penis (superficial fatty fascia is gone here)
colles fascia
located in the region of the urogenital triangle (superficial fatty fascia is gone here)
in general, there is a ____ ____ between the superficial fascia and the deep investing fascia of muscles and structures
facial plane
in certain places, the superficial fascia fuses with the ___ ___ ___
deep investing fascia
scarpa’s fascia will fuse to the investing fascia of the ___ ___
lower limb (fascia lata)
the lateral and posterior edges of colles fascia will fuse to the ___ ___
perineal membrane
the fusing of the fascia has clinical implications why?
it prevents fluid from spreading between the regions
when can you have perforation of the spongy urethra?
during straddle injury
what is the region located posterior to the imaginary line between the ischial tuberosities
anal triangle
what divides the anal triangle into two fat filled spaces
anal canal
the fat filled spaces formed by the anal canal are called what
ischioanal fossae
borders of the ischioanal fossa
- superior- sloping of the levator ani (pelvic diaphragm)
- medial- sloping of the levator ani (pelvic diaphragm)
- lateral- obturator internus m.
- inferior/posterior- skin around the anus
what forms the pudendal canal
the obturator fascia
what does the pudendal canal contain
internal pudendal artery, vein, and pudendal n.
what arteries and nerves supply the anal canal
inferior rectal arteries and nerves as they emerge from the pudendal canal
where does the rectum end
at the floor of the pelvic cavity where the puborectalis m. encircles it
what is the continuation of the rectum
the anal canal that extends inferoposteriorly to terminate at the anus
the wall of the anal canal is composed of what
external and internal anal sphincters
what is the internal anal sphincter
thickened continuation of the inner circular layer of smooth muscle from the rectum
what is the external anal sphincter
composed of skeletal (voluntary) muscle
superficial portion of the external anal sphincter is attached anteriorly to what and posteriorly to what
attached anteriorly to the perineal body and posteriorly to the coccyx
what attaches the superficial portion of the external anal sphincter to the perineal body and coccyx
anococcygeal raphe
the lining of the anal canal exhibits vertical folds of mucous membrane called
anal columns
the recesses between the anal columns are called what
anal sinuses
the anal columns are joined at their inferior ends by horizontal folds called
anal valves
the anal-valves have a __ __ morphology
cup-like
the spaces behind the anal valves are called the
anal crypts
what is the clinical importance of the anal crypts
they can serve as a point for infection that may lead to fistula into the ischioanal fossa
the lower margins of the anal valves form the tooth-like ___ ___
pectinate line (dentate line)
what happens below the pectinate line
important changes including changes in the epithelial lining, arterial supply, venous drainage, and lymphatic drainage
arterial supply above the pectinate line
superior rectal a. and middle rectal a.
arterial supply below the pectinate line
inferior rectal aa.
venous drainage above the pectinate line
hepatic portal system and caval system
venous drainage below the pectinate line
caval system via inferior rectal vv.
lymphatic drainage above the pectinate line
internal iliac lymph nodes (deep)
lymphatic drainage below the pectinate line
inguinal lymph nodes (superficial)
innervation above the pectinate line
autonomic fibers (poor localization)
innervation below the pectinate line
pudendal nerve (precise location)
describe the relationship between the anterior recess of the ischioanal fossa and the ischioanal fossa
the anterior recess is continuous with the fossa as it passes anterior to the ischial tuberosities
the boundaries of the anterior recess of the ischioanal fossa are similar to that of the ischioanal fossa, but what is different?
the inferior wall is the UG diaphragm
