L8.1 Perineum Flashcards
1
Q
Region of the perineum
A
- Perineum is best seen with legs open, separates into urogential triangle and anal triangle (located behind
- Perineum is the region below the pelvic floor
2
Q
Features of the perineum
A
- Perineum is the site of anchoring for penis and clitoris
- Anal triangle is slightly angulated POS
- Triangles divided by line across the ischial tuberosities
3
Q
Significance of the angulation of the vaginal and anal canal
A
- Forms functional sphincters
4
Q
Development of the urogenital/GI system
A
- Common ejection chamber for urogential system and GI tract
- Cloaca
- Made up of endoderm
- Has cloacal sphincter (mesoderm)
- Skin has a rich sensory NS
- Internally different NS and BS
- Partition during development (rectovesical septum)
- Urogenital and anal
- Cloaca
5
Q
Perineal membrane
A
- Perineum has strong support from perineal membrane
- Has deep perineal pouch
- Where skeletal muscles forms sphincters around urethra and vagina
- Allows attachment of external genitalia
6
Q
Deep perineal pouches
A
- External urethral sphincter
- Made up of skeletal muscles (slow twitch fibres)
- Able to maintain tone 24/7
- Relaxed to allow micturition
- Additional sphincter components in Females
- Sphincter urethrovaginalis
- Surrounds urethra and goes on to support the vagina (active muscular support)
- Goes in front of vagina
- Compressor urethrae
- Sphincter urethrovaginalis
7
Q
Superficial perineal pouch
A
- Superficial urogenital muscles
- Bulbspongiosus
- Contracts to expel the last drop of urine
- Attaches to the fibrous N - the perineal body
- Perineal body
- Common sites of attachment for muscles of perineum
- Roots of external genitalia
8
Q
Clitoris
A
- Clitoris is deisnged similarly to the penis
- Made up of bulb on each side
- Crura (homologues of corpus cavernosum in male)
- Erectile tissues
- Glands
- Bulb
9
Q
What happens when the bulbs are damaged
A
- Leads to Extravasation of urine into extraperitoneal tissue of the pelvic cavity
- Damaged by falling onto a beam
10
Q
Features of the female external vaginal components
A
- Vulva
- External genitalia in female
- Labium majora
- Homologue of the scrotum in males
- Labium minora
- Homologue of the spongy urethra in males
- Glands is ANT to urethra (which is just behind the clitoris)
- Glands open up into area called vestibule
- Hymen
- Partitioning the opening of the vagina
11
Q
Ischio (rectal) anal fossa
A
- Contains fat and pudendal N (gives off INF rectal N) to external anal sphincter
- Allws rectum and anua to distent to allow defaecation
- Abscess formation (typically have to be removed)
12
Q
External anal sphincter
A
- Deep part
- Superficial part
- Attach to perineal body
- Forms the raphe to the tips of the coccyx
- Stabliises the perineal body
- Subcutaneous part
- Guards the most superficial part of the anal canal
- Innervated by INF rectal N (branch from S4)
13
Q
Nerves of the perineum
A
- INF retal N (S4) comes from pudendal N
- Pudendal N (S2, 3, 4)
- Supply branches to perineum, rectum, L.A
- Into pelvic cavity via GSF and exits LSF
- Not prone to compression or entrapment
- INF to the pelvic floor
- Pudendal N (S2, 3, 4)