Perineum Flashcards
Ischioanal fossae
Fat filled spaces that support the anal canal while permitting its descent and expansion during defecation
Perineum can be split into two triangles, name them
anal triangle
Urogenital triangle
Ischioanal Fossa communicates with urogenital triangle via the anterior recesses, what is a potential problem with this?
Potential route for the spread of infection
What is the tendinous connection between the anus and coccyx?
anococcygeal raphe
What is important about the pudendal canal? Where is it located?
- passageway for pudendal n. and internal pudendal a. and v.
- Located between Obturator internus and ischioanal fossa
What are the branches off the internal pudendal artery?
*internal pudendal a. comes off internal iliac a.
- inferior rectal
- splits into deep a. of penis (clitoris) and dorsal a. of penis (clitoris)
Where can you find the pudendal n. (S2-4)?
- greater sciatic foramen -> ishcial spine and sacrospinous ligament -> lesser sciatic foramen
- Passes through the pudendal canal and branches to innervate perineal structures
When is the pudendal and ilioinguinal nerve blocks used
- to help with the pain of childbirth
- Pudendal nerve block: inject near ischial spine -> perineal structures numbed
- Ilioinguinal nerve block: for pain of superior aspect of labia majora
The anal canal has different embryological deviation. What line seperates the proximal and distal aspects?
Proximal: endodermally derived
Distal: ectodermally derived
Line: pectinate line
The superior portion of the anal canal recieves what innervation, blood supply; and lymph drainage?
Innervation: Autonomic and visceral sensory
Blood supply : Superior rectal a. and v. (Portal)
Lymph: internal iliac nodes
The inferior portion of the anal canal has what innervation; what blood supply; and what lymph drainage?
Innervation: somatic motor and sensory innervation
Blood supply:inferior and middle rectal a. and v. (Caval)
Lymph: Superficial inguinal nodes
Internal hemorrhoids (“piles”)
- Prolapse of normally distended veins of internal venous plexus
- often compressed by sphincters - impeding blood flow leading to ulceration and strangulation
- Bleeding is bright red
- visceral pain
External hemorroids
- Thromboses (blood clots) in veins of external venous plexus
- predisposing conditions include pregnancy; chronic constipation
- any condition that impedes venous blood flow
- somatic pain
Internal anal spincter: location, what affect does sympathetics and parasympathetics have on it
- Location: smooth muscle sphincter that surrounds superior 2/3 of anal canal
- contraction: maintained (tonic) via sympathetics
- Inhibited by: parasympathetics
External anal sphincter: origin, insertion, innervation, action
O: skin and fascia around arus; coccyx; anococcygeal ligament
I: surrounds lateral aspects of anal canal
N: inferior rectal n.
A: voluntary constriction of anal canal
Fetal incontinence is usually an impairment of 2 of what 3 muscles
- internal anal sphincter
- external anal sphincter
- puborectalis
What is the hood of the clitoris called
prepuce of clitoris
What is the anterior portion of the female external genitalia superficial to pubic bone (grows hair)?
Mons pubis
What is the name of the skin that covers the head of the penis?
prepuce of penis
What membrane attaches the roots of external genitalia and associated muscles?
Perineal membrane
What are corpora cavernosa and corpora spongiosa
spongy erectile tissue in females; females have two of each
Clitoris has two lateral attachments that form from the corpora cavernosa, what are they
crura
What are corpora cavernosa and corpus spongiosum? What structure lies in the corpus spongiosum?
erectile tissue in men; men have only one corpus spongiosum that encloses urethra
What are the two ends of the penis called?
bulb of penis and glans penis
Ishciocavernous is found in both males and females. What is the origin, insertion, innervation, and action
O: internal surface of ischiopubic ramus and ischial tuberosity
I: crus of penis/clitoris
N: pudendal n
A: helps maintain erection
What is the origin, insertion, innervation, and action of Bulbospongiosus in males?
A: compresses bulb, assists erection and ejactulation
O: perineal body, median raphe
I: surrounds bulb of penis
N: pudendal n
O, I, A, N or bulbospongiosus in females
A: assists erection, “sphincter of vagina”
O: perineal body
I: pubic arch, fascia of corpora cavernosa
N: pudendal n
action, origin, insertion, and innervation of superficial transverse perineal in males and females
A: supports and flexes perineal body to pelvic floor; supports pelvic floor
O: ischiopubic ramus and ischial tuberosity
I: perineal body
N: pudendal n.
External urethral sphincter and Compressor Urethrae : action; origin; insertion; innervation in males and females
Action: compress urethra (helps maintain continence); compress vagina (females)
O: ischial tuberosity
I: anterior aspect of urethra
N: dorsal n. of penis/clitoris (branch of pudendal n)
What artery runs in the corpora cavernosa in males
deep artery of the penis
Veins of perineum in males
superficiall dorsal v. of penis: drains to thigh
Deep dorsal v. of penis: drains to pudendal v.
What nerve innervates the perineum in males and females
Paired!
- dorsal nerve of penis/clitoris
* from pudendal n.
(male picture showed)
NAVAN
mneumonic for nerve, artery, vein, artery, nerve in the male penis
What is the deep perineal pouch?
- Location: b/w perineal membrane (pictured as blue line) and pelvic diaphragm
- contains external urethral spincter, glands (in males); included anterior recesses of ischioanal fossa
Superficial perineal pouch
- Location: b/w perineal membrane (blue line) and deep perineal fascia
- contains erectile tissue and associated muscles as well as space between deep and superficial fasciae
Scarpa’s fascia runs continuously around the external genitalia. Name the parts
- superficial fascia of penis
- Dartos fascia: around scrotum
- Colles fascia
fascia beginning from rectus abdominis and External oblique aponeurosis runs deep around the penis. Name the parts
- buck’s fascia
- deep perineal fascia
Rupture of urethra superior to perineal membrane will cause
bloody urine will enter the deep pouch and abdominopelvic cavity
Rupture of urethra inferior to perineal membrane
- break is through corpus spongiosum
- bloody urine will enter the perineal cleft
