DR1: Pelvic Floor

Question 1

What is the perineal membrane?

Answer 1

Thick fibrous membrane sitting beneath the pelvic diaphragm

Question 2

What is the pelvic diaphragm?

Answer 2

Formed by the muscles of the pelvic floor

Question 3

What is the pubic arch?

Answer 3

Runs between the lower edge of the pubic body and the two ischial tuberosities

Question 4

What is the deep perineal pouch?

Answer 4

Formed by the anterior and posterior free edges of the perineal membrane folding upwards

Question 5

What perineal muscles are in the deep perineal pouch?

Answer 5

Compressor urethrae, utherovaginal sphincter in females

Question 6

Describe the superficial perineal pouch.

Answer 6

Inferior to the perineal membrane containing skeletal muscles responsible for erection

Question 7

Describe the perineal body.

Answer 7

Found midway along a line joining the two ischial tuberosities
Site where fibres from several muscles of the superficial perineal pouch converge.

Question 8

What muscles cover part of the pelvis wall?

Answer 8

Piriformis

Obturator internus

Question 9

What is the passageway for the somatic sacral nerves?

Answer 9

Anterior surface of the sacrum

Question 10

Describe the piriformis muscles.

Answer 10

Lies on anterior surface of the sacrum

Question 11

Describe the obturator internus muscle location.

Answer 11

Passes beneath the obturator foramen

Question 12

Describe the tendinous arch.

Answer 12

Used to locate the obturator internus muscle

Question 13

Describe the muscles of the pelvic floor.

Answer 13

Levator ani

Coccygeus

Question 14

What features are associated with the pelvic floor?

Answer 14

Internal surface of the body of pubis
Ischial spine
Coccyx
Tendinous arch

Question 15

Origin and insertion of iliococcygeus

Answer 15

Tendious arch projects from ischial spine to posterior aspect of pubic bone to coccyx

Question 16

Origin and insertion of Pubococcygeus

Answer 16

From internal surface of the pubis to the coccyx

Question 17

Origin and insertion of puborectalis

Answer 17

From pubis with fibres inserted behind the rectum

Question 18

Origin and insertion of coccygeus

Answer 18

Inner surface of the ischial spine to lateral margin of the coccyx and side of the 5th sacral segment

Question 19

Roots of the sacral plexus

Answer 19

Formed by anterior primary rami of S1-4

Question 20

Course of the obturator nerve

Answer 20

Exits the pelvis via the obturator foramen

Question 21

What nerve remains in the pelvis?

Answer 21

Piriformis nerve

Question 22

Lumbosacral trunk

Answer 22

Sacral plexus is joined by the anterior primary rami of the lumbar L4,5

Question 23

Sciatic nerve

Answer 23

L4,5, S1-3

Largest nerve in the body and largest branch of the plexus

Question 24

Superior gluteal nerve

Answer 24

L4,5 plus S1

Question 25

Inferior gluteal nerve

Answer 25

L5, S1, S2

Question 26

Pudendal nerve

Answer 26

S2-4 Exits the pelvis through the greater sciatic foramen then re-enters through the lesser sciatic foramen by crossing over the ischial spine

Question 27

Main branches of the lumbosacral trunk

Answer 27

Sciatic nerve Superior gluteal nerve Inferior gluteal nerve Pudendal nerve

Question 28

Important structures of the posterior pelvis

Answer 28

Sciatic nerve Pudendal nerve Gluteal vessels

Question 29

Sciatic nerve

Answer 29

Widest nerve in the human body as a large amount of myelin is required to insulate the long axons Found inferior to the piriformis muscle (rarely the nerve passes through the piriformis muscle to cause sciatica)

Question 30

Clinical significance of the sciatic nerve

Answer 30

In order to avoid the nerve, injections into the buttocks are always done both lateral and high

Question 31

Pudendal nerve

Answer 31

Target of pudendal block for anaesthetic drug to numb perineal region

Question 32

When is a caudal epidural more common practice than a pudendal nerve block?

Answer 32

When used to alleviate labour pain

Question 33

Superior gluteal artery

Answer 33

Exits the pelvis through the greater sciatic foramen and superior to the piriformis muscle

Question 34

Inferior gluteal artery

Answer 34

Exits the pelvis through the greater sciatic foramen and inferior to the piriformis muscle

Question 35

Superior and inferior gluteal veins

Answer 35

Adjacent to superior and inferior gluteal arteries