Pelvis and Perineum

Question 1

What are the margins of the pelvic inlet?

Answer 1

Sacral promontory

Margin of ala

Sacroiliac joint

Arcuate line

Pectineal line (pecten pubis)

Pubic crest

Pubic symphysis

Question 2

What are the parts of the linea terminalis?

Answer 2

Pubic crest

Pecten bupis

Arcuate line

Question 3

What are the boundaries of the pelvic outlet?

Answer 3

Coccyx

Sacrotuberous ligament

Ischial tuberosity

Pubic arch

Pubic body

Pubic symphysis

Question 4

What are the differences between male and female pelvis?

Answer 4

Hearth shaped inlet in males round in females

Obturator foramina face anteriorly in females

Pubic arch is larger in females (~120 degrees)

Pelvic inlet and outlet are wider in females than males.

Iliac crest is shorter and wider in females than in males.

Question 5

What is the bulb of the penis/vestibule connected to?

Answer 5

The body of the pubis.

Question 6

What are the 2 triangles formed when a horizontal line is drawn between ischial tuberosities?

Answer 6

Urogenital triangle (with vaginal opening or urethral opening in females and internal urethral sphincter of the penis)

Anal triangle (with coccyx)

Question 7

What are the most superficial muscles of the pelvic floor and what do they do?

Answer 7

The ischiocavernosus (from ischial tuberosity to the crus of the clitoris) and the bulbospongiosus (from perineal body to the bulb of the vestibule and body of clitoris).

Ischiocavernosus allows blood to move from the crus of the clitoris to the bulb/glans of the clitoris.

Question 8

What are the deep muscles of the pelvic floor?

Answer 8

Urogenital diaphragm (external urethral sphincter, and deep transverse perineal)

Pelvic diaphragm (Levator ani, external anal sphincter and coccygeus)

Question 9

What is the nerve supply of the ischiocavernosus and Bulbospongiosus?

Answer 9

The pudendal nerve

Question 10

Where does the external urethral sphincter originate and insert?

Answer 10

O - Ischiopubic rami

I - Encircles membranous part of the urethra

Question 11

What provides the external urethral sphincter with its nerve supply?

Answer 11

Pudendal nerve and spinal nerve of S4

Question 12

What does the external urethral sphincter do?

Answer 12

Compresses the membranous urethra and relaxed during micturition

Question 13

What are the origin and insertion and action of levator ani?

Answer 13

O - Ischial spine and pubis

I - Coccyx, wall of urethra, vagina, and anus

A - Supports pelvic viscera and raises the pelvic floor.

Question 14

What is the origin, insertion and action of coccygeus?

Answer 14

O - Spine of ischium

I - Coccyx and adjacent border of sacrum

A - Supports pelvic viscera and brings coccyx forward

Question 15

What is the nerve supply of levator ani?

Answer 15

Pudendal nerve

Spinal nerve S4

Question 16

What is the nerve supply of coccygeus?

Answer 16

Spinal nerve S4 - S5

Question 17

What is the origin and insertion and action of the ischiocavernosus in males?

Answer 17

O - Ischial ramus and tuberosity

I - Crus of penis

A - Move blood from crura into body of erect penis

Question 18

What is the origin and insertiona and action of bulbospongiosus?

Answer 18

O - Perineal body and median raphe

I - Perineal membrane and bulb of penis

A - Removal of residual urine from the urethra; Pulsatile ejaculation of semen

Question 19

What nerve supplies both the bulbospongiosus and ischiocavernosus in males?

Answer 19

The pudendal nerve

Question 20

What does the pudendal nerve do?

Answer 20

Motor: supplies skeletal muscles of perineum including the external urethral and anal sphincters as well as levator ani.

Sensory: Most skin of the perineum, penis and clitoris.

Question 21

Where does the pudendal nerve originate and how does it travel?

Answer 21

Originates at sacral plexus at S2 - S4 and travels along the sacrospinous ligament then passes ischial spine (landmark for anaesthetics) and descends from there