The perineum Flashcards
What is the most inferior region of the pelvic outlet?
Perineum
What are the borders of the perineum?
Front= pubic symphysis Back= coccyx Sides= Ischial tuberosities
Two triangles of perineum
Urogential and anal
Which of the urogenital and anorectal triangles is the most vericle?
Anorectal
What does the pudendal nerve branch into?
Perineal nerve, inferior rectal nerve, dorsal nerve of penis/ clitoris
What is the arterial supply for the perineum?
Internal pudendal artery
Where does the pudendal vein originate?
Rami of S2-S4
Describe the course of the pudendal vein?
Exits pelvis through greater sciatic foramen
Passes through ischial spine
Enters perineum through lesser sciatic foramen, passes into pudendal canal
What is the pudendal canal formed by?
Fascia overlying obturator internus
What are ishioanal fossae?
Spaces located in anus, allowing for expansion
What divides the urogenital trangle into deep and superficial?
Perineal membrane
What is the hole in perineal membrane for?
Passage of urethra
Names of two superficial fascia?
Campers and Colles
What is Camper’s fascia
Layer of abdominal wall continuous with ishioanal fossae and superficial fascia of thigh
What is Colles fascia?
Continuous with anterior abdominal wall but NOT THIGH FASCIA
Deep to camper’s
Where is the deep perineal pouch?
Above the perineal membrane
What muscles are contained in the deep perineal pouch
Deep transverse perineal muscles
External urethral sphincter
What is function of deep transverse muscles
Support to anal canal and perineum
What glands found in deep perineal pouch?
Cowpers gland
Bulbourethral gland
Where is the superficial perineal pouch?
Between perineal membrane and Colle’s fascia
What muscles are found in superficial perineal pouch
Superficial transverse muscles
Bulbospongiosus
Ischiocavernosus
What is the perineal body?
Junction of two triangles: irregular fibrocollagenous mass
What attaches to perineal body?
Levator ani
Bulbospongiosum
Superficial and deep transverse muscles
External anal and urethral sphincters
What makes up glans penis dorsally and ventrally?
Dorsal: corpus cavernosa
Ventral: corpus spongiosum
What is the proper word for foreskin?
Prepuce
What vessels are found on dorsal surface of penis?
Dorsal vein, artery and nerve
Function of Buck’s fascia?
Blocks drainage, keeping more blood in penis
What is the base of corpus cavernosum called?
Crura
What does the ischiocavernosus overlie and what is its function?
Corpus cavernosus
Compresses crura to keep blood within structure during erection
What does bulbospongiosus cover?
Bulb of penis
Corpus spongiosum
How does parasympathetic nervous system drive an erection?
NO release (potent vasodilator)
Which part of the penis becomes erect and what stays flacid- why?
Corpus cavernosum engorges with blood
Corpus spongiosum remains flaccid to protect the urethra
What do Cowpers glands do?
Produce pre-ejaculate to ready the urethra for ejaculation
How does sympathetic nervous system drive ejaculation?
Stimulates smooth muscle in lining of epididymis, vas deferens, seminal vesicles and prostate
What is the purpose of sphincter of bladder contractions during ejaculation?
Prevents ejaculate from going back into bladder
What is contained in the vestibule of the vagina?
Urethral and vaginal openings
What is the perineal raphe?
Line from inferior aspect of vagina to anus
What is the erectile tissue of the female genitalia?
Bulb of vestibule, crura of clitoris
What is the function of bulbospongiosus in women?
Reduces size of vaginal orifice, compressing dorsal vein of clitoris
