Lecture 18 DA

Question 1

Where does piriformis originate and insert?

Answer 1

It originates from the three midsections of the sacrum and exits the pelvis through the greater sciatic foramen, and attaches on the lower limb.

Question 2

Where does obturator internus originate from?

Answer 2

It originates from the obturator foramen, exits through the lesser sciatic foramen, just under the sacrospinous ligament.

Question 3

What lines the obturator internus? What attaches here?

Answer 3

Obturator fascia lines it. In the middle of obturator internus, it is thickened, called tendinous arch. The levator ani attaches here.

Question 4

How does the levator ani split the pelvic cavity?

Answer 4

It partitions it into the cavity above and the perineum below.

Question 5

What is within the perineum?

Answer 5

Rectum, vagina and urethra.

Question 6

What is the pelvic floor?

Answer 6

Levator ani, also known as the pelvic diaphragm as it acts like one, maintaining pressure.

Question 7

Where does the levator ani project and what does it do to foetal heads?

Answer 7

It projects medially, and rotates the head 90 degrees.

Question 8

What is found between the levator ani and the obturator internus?

Answer 8

The pudendal canal. Neurovascular bundle travels through here, the pudendals.

Question 9

What is the major artery of the pelvis?

Answer 9

Common iliac artery.

Question 10

Where do the internal and external iliac arteries supply?

Answer 10

External - lower limb.

Internal - Pelvis.

Question 11

What is the raphe?

Answer 11

A tendinous line formed by the levator ani.

Question 12

What is a consequence of a weak levator ani?

Answer 12

Visceral prolapse distally, as well as urinal and faecal incontinence.

Question 13

What is a complication of prostatectomy or childbirth regarding internal viscera?

Answer 13

They can both cause distal prolapse.

Question 14

What is a complication of prostatectomy regarding nerves?

Answer 14

Nerve supplying rectum and urethra can be damaged, resulting in faecal and urinal incontinence.

Question 15

What happens in a prolapse?

Answer 15

Pelvic floor stretches, and viscerafall through.

Question 16

Describe the pubococcygeus.

Answer 16

Found deeply. Has puborecalis within it. Under reflex control in children. When nervous system matures, it goes under voluntary control. Puborectalis is deep to pubococcygeus, and passes around the anal canal like a sling, causing a kink at the recto-anal junction. Prevents involuntary defaecation. Rectum is only somewhat straighter during defaecation.

Question 17

Describe the structure and function of puborectalis, pubovaginalis and puboprostaticus.

Answer 17

Sling like, fuses with the deep part of the external anal sphincter.
Pubovaginalis/puboprostaticus stabilise the vagina or prostate. Puboprostaticus attaches from pubis to prostate.

Question 18

What is the prostatic urethra?

Answer 18

Urethra within the substance of the prostate.

Question 19

Describe the iliococcygeus.

Answer 19

In between pubococcygeus and ischiococcygeus. Sits on top of the sacrotuberous ligament.
It is the agitator caudae in animals, moving the tail. Commonly absent or very few fibres.

Question 20

Describe the ischiococcygeus.

Answer 20

It is the most posterior component of levator ani.

Question 21

What are the three components of levator ani from anterior to posterior?

Answer 21

Pubococcygeus
Iliococcygeus
Ischiococcygeus

Question 22

Is the levator ani always under pressure?

Answer 22

Yes, especially during childbirth.

Question 23

What is the peineal body?

Answer 23

Midline fibrous nodule, larger in females than males, and is in the perineum. Muscles merge with the perineal body and stabilise it.

Question 24

What are thr functions of the pelvic floor?

Answer 24

Supports pelvic viscera.
Raises the pelvic floor.
Continence, faecal and unrinal.
Childbirth, creates a gutter to enable foetal head rotation.

Question 25

What is the nerve supply to the pelvis?

Answer 25

Segmental from S3 and S4 above.
Pudendal from S2 and S3 below, enters the gluteal region with the gluteal artery, but exits via the lesser sciatic foramen.

Question 26

What nerve is in danger if trauma occurs to the perineal region?

Answer 26

Pudendal nerve can be damaged.

Question 27

What nerve is anaesthetised during childbirth by obstetricians, and what landmark is used to find it?

Answer 27

The pudendal nerve, ischial spine used as a landmark.

Question 28

Where is the urogenital hiatus found, what what passes through it?

Answer 28

Found anteriorly, vagina passes through it.

Question 29

Which viscera can prolapse?

Answer 29

Uterus - urethrocoele
Bladder - cystocoele
Rectum - Rectocoele