The Pelvis as a Region of Anatomy of the Body

Question 1

List the surface areas of the abdomen on the left and right sides from superficial to inferior.

Answer 1

1 - Hypochondriac.

2 - Lumbar.

3 - Iliac.

Question 2

List the surface areas of the abdomen on the central line from superficial to inferior.

Answer 2

1 - Epigastric.

2 - Umbilical.

3 - Hypogastric.

Question 3

List the superior, inferior, anterior, posterior and lateral borders of the abdominopelvic cavity.

Answer 3

• Superior:

1 - The inferior border of the diaphragm.

Inferior:

1 - Pelvic floor.

2 - Perineum.

Anterior:

1 - Anterior abdominal muscles (anterosuperior).

2 - Anterior border of bony pelvis (anteroinferior).

Posterior:

1 - Ribs (posterosuperior).

2 - Vertebral column (posterosuperior).

3 - The sacrum (posteroinferior).

Lateral:

1 - Ribs (superolateral).

2 - Thigh (inferolateral).

Question 4

List the bones of the pelvis.

Answer 4

1 - Sacrum.

2 - Ilium.

3 - Ischium.

4 - Pubis.

5 - Coccyx

Question 5

What are the superior and inferior apertures of the pelvis otherwise known as?

Answer 5

• The superior aperture is also known as the pelvic inlet.

- The inferior aperture is also known as the pelvic outlet.

Question 6

List the palpable bony components of the pelvic inlet.

Answer 6

1 - Highest point, known as the supracristal plane.

2 - Middle point, known as the transtubercular plane.

3 - Lowest point known as the pelvic brim.

Question 7

Which vertebral level corresponds to the highest palpable point of the pelvic inlet / the supracristal plane?

Answer 7

L3/4 intervertebral disc.

Question 8

List 2 anatomical structures that occur at the level of the supracristal plane.

Answer 8

1 - The bifurcation of the abdominal aorta into the common iliac arteries.

2 - The umbilicus.

Question 9

Which vertebral level corresponds to the middle palpable point of the pelvic inlet / transtubercular plane?

Answer 9

L5.

Question 10

Which structures does the transtubercular plane intersect?

Answer 10

The iliac tubercles.

Question 11

Which bony component of the pelvis forms the pelvic brim?

Answer 11

The pubic crest.

Question 12

Which structure divides the pelvis into the greater and lesser pelvises?

Answer 12

The pelvic brim.

Question 13

List the contents of the greater pelvis.

Answer 13

1 - Colon.

2 - Iliacus.

3 - Psoas major and minor.

Question 14

List the contents of the lesser pelvis.

Answer 14

1 - Reproductive system.

2 - urinary system.

3 - Terminal portion of the digestive system.

Question 15

Which artery supplies all of the organs of the lesser pelvis?

Answer 15

The internal iliac artery.

Question 16

What is the rectovesical pouch?

Answer 16

• In the male pelvis, the parietal peritoneum separates the urinary bladder (anteriorly) from the rectum (posteriorly).
• As the parietal peritoneum courses between the two, it forms a pouch known as the rectovesical pouch.

Question 17

What are the rectouterine and vesicouterine pouches?

Answer 17

• In the female pelvis, the parietal peritoneum separates the urinary bladder (anteriorly) from the uterus (midway) and the rectum (posteriorly).
• As the parietal peritoneum courses between the three, it forms two pouches - the rectouterine and vesicouterine pouches.

Question 18

What is the rectouterine pouch otherwise known as?

Answer 18

The pouch of Douglas.

Question 19

What is the space of Retzius?

Answer 19

The potential space between the pubic symphysis and the bladder.

Question 20

What is the perineal body?

How does it affect the appearance of the region in which it is found?

Answer 20

• A thickening of fascia in the pelvic floor that acts as a point of attachment of muscles.
• It causes the pelvic floor to adopt a hammock-like shape.

Question 21

List the anterior, posterior and lateral attachments of the pelvic floor.

Answer 21

• Anteriorly, the pubis.
• Posteriorly, the coccyx.
• Laterally, a thickened band of the obturator fascia.

Question 22

What are the urogenital and anal triangles?

Answer 22

• The pelvic outlet has a diamond shape.
• If a horizontal line is drawn through the perineal body, the diamond is bisected into two triangles.
• The anterior triangle is known as the urogenital triangle.
• The posterior triangle is known as the anal triangle.

Question 23

Which structure defines the openings of the urethra and vagina?

Answer 23

The perineal membrane.

Question 24

What structure anchors the perineal membrane at the midline?

Answer 24

The perineal body.

Question 25

List 5 muscles anchored at the perineal body.

Answer 25

1 - The external anal sphincter.

2 - The external urethral sphincter.

3 - Superficial transverse perineal muscle.

4 - Deep transverse perineal muscle.

5 - Bulbospongiosus.

Question 26

List the layers of the pelvic floor from superior to inferior.

Which of these layers comprise the pelvic diaphragm?

Answer 26

The pelvic floor consists of the pelvic diaphragm and perineum:

1 - Internal layer of fascia.

2 - Levator ani (anteriorly) and coccygeus muscles (inferiorly).

3 - External layer of fascia.

4 - Perineal membrane.

5 - Perineum.

• Layers 1-3 comprise the pelvic diaphragm.

Question 27

What is the superficial perineal pouch?

Answer 27

A potential space between the perineal membrane and the perineum.

Question 28

What is the deep perineal pouch?

Answer 28

A potential space between the external layer of fascia of the pelvic diaphragm and the perineal membrane.

Question 29

List the muscles comprising the levator ani.

Which muscle forms the main part of levator ani?

Answer 29

1 - Puborectalis.

2 - Pubococcygeus (main muscle).

3 - Iliococcygeus.

Question 30

Describe the course of the puborectalis muscle.

What is the function of its shape?

Answer 30

• Arises from the pubis.
• Passes posteriorly to unite with the other puborectalis muscle, forming a U shaped sling around the anorectal junction.
• The sling maintains anorectal flexure, contributing to continence.
• Some fibres of puborectalis insert into the deep part of the external anal sphincter.

Question 31

How does the puborectalis muscle differ between males and females?

Answer 31

• In males, some fibres pass more anteriorly around the prostate, forming the levator prostatae muscle.
• In females, some fibres pass as a sling behind the vagina, inserting into the perineal body and forming the pubovaginalis muscle.

Question 32

Describe the course of the pubococcygeus muscle.

Answer 32

• It arises from the pubis.

- It runs posteromedially to insert into the coccyx and anococcygeal ligament.

Question 33

How does the pubococcygeus muscle differ between males and females?

Answer 33

In females, it also encircles the urethra, vagina and anus, merging into the perineal body.

Question 34

Describe the course of the iliococcygeus muscle.

Answer 34

• It arises from the lateral pubic symphysis.
• It travels laterally over the obturator internus.
• It meets in the midline with the other iliococcygeus muscle and continues to insert at the coccyx.