Flashcards in Perineum Deck (46):
What is the perineum bounded by?
3. Ischial tuberosity
What are the 2 divisions of the perineum?
1. anal triangle - posterior
2. urogenital triangle- anterior
Describe the anal triangle
contains the anal canal that can be divided into upper and lower halves
contains the ischioanal fossae
Characteristics of the ischioanal fossae
1. Full of fat for expansion and cushion
2. Pudendal canal for the pudendal nerve, internal pudendal artery and vein
What are the branches of the pudendal nerve?
1. inferior rectal nerves
2. dorsal nerves of penis or clitoris
What are the branches of the internal pudendal artery?
1. Inferior rectal artery
2. External genital artery
Upper half of the anal triangle
Above the pectinate line
1. No pain receptors
2. Derived from endoderm
3. Anal columns present
5. Autonomic innervation
6. Superior rectal artery and middle rectal artery
Lower half of the anal triangle
Below the pectinate line
1. Pain, stretch, and sensation receptors (clinically important for hemorrhoids)
2. Somatic innervation from inferior rectal branch of pudendal
3. Inferior rectal arteries
Internal anal sphincter
Located next to anal canal
External anal sphincter
Located next to levator ani muscle
Voluntary and innervated by inferior rectal nerve
Male vs. Female urogenital triangle
1. Testes = ovaries
2. Body of penis = body of clitoris
3. Penile raphe and spongy urethra = labium minora
4. scrotum = labia majora
5. Bulbourethral gland = greater vestibular gland
6. Prostate gland = Paraurethral gland/lesser vestibule
7. Gubernaculum = round and ovarian ligament
What are the parts to the root of the penis?
2. left and right crura
What is the bulbospongiosus muscles job?
1. Covers the bulb
2. squeeze to keep the penis erect and empty the urethra
What is the ischiocavernosus muscles job?
1. Covers the left and right crura
2. Squeeze to keep the penis erect and push blood distally
What do the bulb and crura become?
Bulb = corpus spongiosum
Crura = corpus cavernosum
What does the body contain?
Three cylinders of erectile tissues
1. Corpus spongiosum
2. Corpus cavernosa x2
What does the corpus spongiosum contain and do?
Contains the urethra and expands to form the glans
Fills with blood to keep the penis erect
Characteristics of the superficial perineal pouch
1. Potential space
2. bounded laterally by ischiopubic rami
3. Proximal spongy urethra and root of penis here
4. 3 muscles connect here
What are the 3 muscles of the superficial perineal pouch?
1. bulbospongiosus muscle
2. Ischiocavernous muscles x2
3. Superficial transverse perineal muscle
What are all the muscles of the superficial pouch innervated by?
Perineal nerve of pudendal nerve
Origin and insertion of the superficial transverse perineal muscle?
O: ischial tuberosity
I: perineal body
Characteristics of deep perineal pouch
1. Includes fat filled ischioanal fossae
2. Contains intermediate urethra, bulbourethral glands
3. Sphincter urethrae- external
4. Deep transverse perineal muscle
5. Dorsal nerve of penis
6. Dorsal artery to bulb of penis
7. dorsal arteries of the penis
2. voluntary- allows release of urine
3. Innervated by perineal branch of pudendal nerve
Characteristics of deep perineal muscle
1. extends from ischial ramus to perineal body
2. Supports pelvic floor and expel residual semen and urine
3. innervated by perineal branch of pudendal nerve
What does the dorsal nerve of the penis innervate?
skin of penis and glans of the penis
What does the dorsal artery to the bulb of the penis supply?
1. posterior corpus spongiosum
2. bulbourethral gland
What do the dorsal arteries of the penis supply?
fibrous tissue around corpora and skin
What do the deep arteries of the penis supply?
1. Fill crura and corpus cavernosa with blood
2. Aid in erection
Parts of the vagina
2. Labia majora
3. Labia minora
4. Mons pubis
Characteristics of the clitoris
2. Erectile tissues present covered by bulb of vestibule, left and right crura
3. Body- Corpus cavernosa x2 and slender erectile body from the bulb
Female superficial perineal pouch contents
2. Bulbospongiosus muscle
3. Ischiocavernosus muscle
4. Greater vestibule glands
5. Paraurethral glands/ lesser vestibular glands
6. Superficial transverse perineal muscles
Characteristics of female bulbospongiosus muscle
1. covers bulb of vestibule and greater vestibular glands
2. constrict vagina
3. Innervated by perineal nerve of pudendal nerve
What nerve innervates the female superficial perineal pouch?
Perineal nerve of pudendal nerve
What does the ischiocavernosus muscle do in females?
assists in erection of the clitoris
What do the greater vestibular glands do?
Secrete lubricating mucus during sexual arousal
What do the paraurethral/lesser vestibular glands do?
secrete fluid into vestibule for distribution to labia
What do the female superficial transverse perineal muscles do?
support/fix perineal body to support pelvic viscera and resist increased intra-abdominal pressure
What is an episiotomie?
Cut perineal body before child birth and causes the need to strengthen the perineal muscles
Don't strengthen the muscles risk of uterine prolapse occurring
Contents of female deep perineal pouch
1. part of urethra
2. part of vagina
3. sphincter urethrae
4. deep transverse perineal muscles
5. posterior labial branches of internal pudendal artery
6. artery to bulb of vestibule
7. Deep artery of clitoris
8. Dorsal artery of clitoris
8. Dorsal nerves of clitoris
Characteristics of deep transverse perineal muscles
1. located on internal surface of ischiopubic ramus and ischial tuberosity to perineal body
2. Same action as superficial transverse perineal muscles = support/fix perineal body to support pelvic viscera and resist increased intra-abdominal pressure
What do the posterior labial branches of the internal pudendal artery supply?
skin of labia majora and minora
What does the deep artery of the clitoris supply?
erectile tissues of the clitoris
What does the dorsal artery of the clitoris supply?
1. deep perineal pouch
2. erectile tissues of clitoris
What are somatic nerves roles within the pelvic region?
1. voluntary control
2. Come out via pudendal nerve (S2-S4)
3. Present in pelvic floor muscles and external sphincter (both)
4. Sensory fibers- know when you have a bladder infection
What are sympathetic nerve roles in the pelvic region?
3. Contracts internal anal sphincter and male internal urethral sphincter
4. Contracts ductus deferens, seminal vesicles, and prostatic muscles
4. Sensory fibers but poorly localized- no pain receptors