Repro - Perineum

Question 1

Where is the perineum found?

Answer 1

Inf to the pelvic diaphragm, being the most inferior portion of the trunk

Question 2

What structures are within the boundaries of the perineum?

Answer 2

• external Genitalia
• Perineal Muscles
• Anal Canal

Question 3

How do we divide the peroneum up ?

Answer 3

Into two triangles:

• Anterior or Urogenital (Inf to Pubic symphisis)
• Posterior or Anal (Ant/inf to coccyx)

Question 4

What is the peritoneal membrane?

Answer 4

A thin sheet of deep fascia stretching between the right and left pubic arch below the symphisis
Ext genitalia are affixed to it

Question 5

Your’e looking at the perineum from underneath with the skin etc cut away. Name the 4 major perineal muscles?

Answer 5

Ischiocaverosus
Bulbospongiosus
Superficial & deep Transverse Perineal Muscles
Ext Anal Sphincter

Question 6

What nerve innervates the perineal muscles?

Answer 6

Muscular branch of the perineal nerve, itself a branch of the pudendal nerve (S2-4)

Question 7

Function of the Ischiocavernosus?

Answer 7

Stabilizes erect penis
Tenses Vagina during orgasm
Flexes Anus in both genders

Question 8

Function of the Bulbospongiosus?

Answer 8

Erection (penile & clitoral)

Contractures of orgasm

Question 9

Function of the superficial perineal muscle?

Answer 9

FIxes the perineal body in place

Question 10

Function of the deep perineal muscle?

Answer 10

Fixes perineal body
Supports pelvic floor
Expels semen and last drops of urine (both genders)

Question 11

What is the perineal body?

Answer 11

Central tendon of the perineum. Its found between the vagina/penis and anus.

The Ext Anal sphincter, Bulbospongiosus, Superficial/deep transverse perineal muscles and Ant fibres of levator ani all converge here

Question 12

How is the perineal body clinically significant as part of reproduction ?

Answer 12

It can tear during vaginal birth which predisposes to prolapse of the uterus, rectum or bladder

Question 13

How do we avoid the perineal body and surrounding tisuses tearing during birth?

Answer 13

Episiotomy, ideally mediolateral or lateral rather than midline

Question 14

We have two pouches or potential spaces in our perineum, what are they called and what traverses them?

Answer 14

Superifical and Deep Perineal Pouch/space

The Urethra

Question 15

What space is the ext urinery sphincter found?

Answer 15

Deep Perineal Space

Question 16

Where is the Int Urinary SPhincter found?

Answer 16

In the Subperitoneal space

Question 17

What muscle is found in the deep perineal space?

Answer 17

Deep Transverse perineal muscle

Question 18

What are the widest and narrowest parts of the urethra?

Answer 18

Widest is the prostatic
Narrowest is the membranous (as it passes through the ext urethral sphincter)

Penile or spongy is somewhere in between

Question 19

What “structure” allows the anal canal to expand when you defecate?

Answer 19

The Ischio-anal or Ischio-rectal fossae

Question 20

Where are the ischio-anal fossae found?

Answer 20

Inferior to the pelvic floor and lateral to the anal canal

Question 21

What is found in the ischio-anal fossae?

Answer 21

Adipose tissue, this along with proximity to bowel makes it vulnerable to infections

Pudendal Canal contents

Question 22

What is included in the pudendal canal and how does it enter the ischio-anal canal?

Answer 22

Internal Pudendal Art
Internal Pudenal Vein
Pudendal Nerve

It’s the site of a pudendal nerve block and enteres the ischio-anal fossae through the Lesser Sciatic Foramen