The Perineum

Question 1

Triangles of the perineum

Answer 1

ANTERIOR UROGENITAL TRIANGLE

POSTERIOR ANAL TRIANGLE

Question 2

Contents of anal triangle

Answer 2

Anal aperture – the opening of the anus.

External anal sphincter muscle – voluntary muscle responsible for opening and closing the anus.

Ischioanal fossae (x2) – spaces located laterally to the anus.

Question 3

Innervation of the anal triangle

Answer 3

Alongside the perineum, the anal triangle is innervated by pudendal nerve supplying somatic fibres

Question 4

Contents of the urogenital triangle - deep perineal pouch

Answer 4

potential space between pelvic floor and perineal membrane

• ext. urethral sphincter, vagina
• bulbourethral glands, deep transverse perineal muscles

Question 5

What divides the deep and superficial perineal pouches?

Answer 5

The perineal membrane, perforated by the urethra (and vagina)

*provides attachment for external muscle genitalia§

Question 6

Contents of the urogenital triangle - superifcial perineal pouch

Answer 6

potential space between perineal membrane and superficial perineal fascia

*erectile tissues = ischiocavernosus, bulbospongiosus

• superficial transverse perineal muscles
• greater vestibular glands / bartholin’s glands

bounded to perineal body

Question 7

Significant muscle attachments in the perineum

Answer 7

perineal bodies

anococcygeal bodies

Question 8

Male urethra

Answer 8

PROSTATIC
- at neck of bladder, internal sphincter
- widest most dilated
- ejaculatory duct entry

MEMBRANOUS
- narrowest
- external sphincter

SPONGY / BULBOUS
- receipt of bulbourethral gland

NAVICULAR FOSSA: dilatation at the glans of penis

Question 9

vascular supply of the male urethra

Answer 9

inferior vesical artery

bulbourethral artery

internal pudendal artery.

Question 10

Nerve supply of the urethra

Answer 10

prostatic plexus

Question 11

LYMPH drainage of urethra

Answer 11

prostatic and membranous portions drain to the obturator and internal iliac nodes,

the penile urethra drains to the deep and superficial inguinal nodes.

Question 12

Location of urethra in females

Answer 12

internal = neck of bladder

external = distal end, orifice at the vetibule (opening) - voluntary, deep perineal branch

Question 13

Vascular supply of female urethra

Answer 13

• internal pudendal arteries
  vaginal arteries
  inf. vesical branches
• pudendal nerve

Question 14

Female external genitalia

Answer 14

1. mons pubis
2. labia maj. - hair skin folds
3. labia min. - fuse with clitoris and extend posteriorly of the vestibule
4. Vestibule - opening enclosed by labia min.
   - vaginal introitus
   - urethra
5. bartholin’s glands - lubricating mucus
6. clitoris - beneath clirotal hood
   - corpora cavernosa: erectile

Question 15

Vascular supply of the vulva

Answer 15

• internal and external pudendal arteries
• pudendla veins + labial veins
• LN: superficial inguinal lymph nodes
• pudendal nerve

Question 16

Support structures of the vulva

Answer 16

• BULBOSPONGIOSUS lies laterally to the vestibule
• ISCHIOCAVERNOSUS
• transverse perineal muscle
• external anal sphincter
• levator ani