Exam #4: Perineum II Flashcards
What does the deep (investing fascia) of the perineum envelop? What is it fused to?
Muscles of the perineum
- Ischiocavernosus
- Bulbospongiosus
- Superficial transverse perineal
Suspensory ligament of the penis or clitoris
What is Buck’s Fascia?
- Continuation of the deep fascia in the penis
- Surrounds the corpora cavernosa & corpus spongiosum in the penis
- Is surrounded by the superficial penile fascia
What is the male superficial perineal pouch? What are its borders?
A potential space between Colles fascia & the perineal membrane superior to it. Borders=
- Membranous/ Colles Fascia
- Perineal Membrane
What is the perineal membrane?
Thin inferior fascia of the UG diaphragm
What are the borders of the male deep perineal pouch?
- Superior fascia of UG diaphragm
- Inferior fascia of UG diaphragm (perineal membrane)
What are the contents of the male superficial perineal pouch?
- Root of penis
- Ischiocavernosus m.
- Bulbospongiosus m.
- Superficial transverse perineal m.
- Spongy urethra
What is the deep perineal pouch? What are the borders of the deep perineal pouch, & what are the contents of the male deep perineal pouch?
A space between the perineal membrane & the superior fascia of the urogenital diaphragm.
- Membranous urethra
- External urethral sphincter
- Bulbouretheral (Cowper’s) gland
- Deep transverse perineal m.
- Dorsal nerve of penis
- Internal pudendal & arterial branches
What fascia attaches to & contains the dartos muscle in the scrotum?
Colles Fascia (formerly Scarpa’s Fascia in abd.)
What is the function of the dartos muscle?
- Smooth muscle
- Helps elevate the testis a little w/ wrinkling
- Thermoregulation
What innervates the dartos muscle?
Genital branch of genitofemoral nerve
Describe the fascial layers of the penis from superficial to deep.
Superficial= Colles Fascia that surrounds the penis under skin
Deep= Buck’s Fascia, which binds erectile bodies together
Tunica Albuginea= surrounds the corpora cavernosa & corpus spongiosum (erectile bodies)
What is the root of the penis?
Attached part of the penis that contains three erectile tissues:
- Bulb–corpus spongiosum attached to the perineal membrane of UG diaphragm
- R & L crura–corpus cavernosum, attached to ischiopubic rami
What is the body of the penis?
Continuation of erectile tissues from root:
- 1x Corpus spongiosum, cont. of bulb
- 2x Corpus cavernosum, cont. of crura
Where does the proximal spongy urethra open?
External uretheral meatus
What muscles cover the bulb & crura?
Bulb= Bulbospongiosus m. Crura= Ischiocavernosus m.
What is the function of the bulbospongiosus muscle?
Compress bulb which:
- Empties the spongy urethra of residual urine/ semen
- Erection
What is the function of the ischiocavernosus muscles?
Compress crura which achieves & maintains erection
What are the superficial transverse perineal muscles?
Small muscles arising from ischial tuberosity & inserting into perineal body
What is the perineal body?
Small fibrous mass in center of perineum
What structures attach to the perineal body?
- External anal sphincter
- Bulbospongiosus
- Superficial transverse perineal muscles
What two muscles are contained within the male deep perineal pouch?
1) External sphincter urethrae
2) Deep transverse perineal muscle
What is the bulbourethral gland & what is its function?
- Gland of the male deep perineal pouch w/ ducts extending into the spongy urethra
- Functions to produce fluid that a) neutralizes the acid pH of urine & b) lubricates penis during sexual arousal (doesn’t contribute much)
What is the mons pubis?
- Region of the “vagina” above the clitoris (pubic hair)
- Fat filled for protection during intercourse
What are the labia majora?
- Homologous structure to scrotum
- Prominent fold of skin that is fat filled (protection)– has pubic hair
What are the labia minora?
Delicate mucus membrane folds medial to labia majora
What is the vestibule? What does it contain?
Space between labia minora
- External meati of urethra
- Vagina (vaginal opening)
- Greater vestibular glands
What is the function of the greater vestibular glands?
Secretion of lubricating fluid for intercourse
What is the prepuce?
Hood that protects the clitoris
What is the frenulum?
Fold of mucus membrane between clitoris & labia minora
How does the erectile tissue of the female differ from the male?
- Bulb of the vestibule is homologous with the bulb of the penis & corpus spongiosum; however, it is divided into 2x parts & does NOT have an erectile function
- There are R & L crura w/ corpus cavernosa that DO have erectile function
Only the corpus cavernosa in the female is erectile
What muscles cover the vestibular bulbs?
Bulbospongiosus m.
What muscles cover the R & L crura in females?
Ischiocavernosus m.
How is a pudendal nerve block performed?
1) Insert fingers into vagina
2) Palpate IT
3) Inject anesthetic toward IT
What is a complication of damage to the perineal body during parturition?
Prolapsed uterus
What is an episiotomy?
A surgical incision posterior or lateral from the vaginal opening to aid in parturition & provide clean edges of skin for repair
Describe the general innervation of the perineal organs (somatic, sympathetic, & parasympathetic).
Somatic= Pudendal Nerve (S2-4) Sympathetic= T11-L2 Parasympathetic= S2-4 (Pelvic splanchnic nerves)
What is the mnemonic to remember the innervation of sexual function?
Point= Parasympathetic (Erection) Shoot= Sympathetic (Emission) Score= Somatic (Ejaculation)
How do the autonomic nervous systems function in ejaculation?
Sympathetics= close internal urethral sphincter (prevent reflux) Parasympathetics= contract urethral muscle
