Pelvis and perineum anatomy

Question 1

What bones form the pelvis?

Answer 1

The pelvis is formed by the sacrum, coccyx, and a pair of hip bones (ilium, ischium, and pubis).

Question 1

What are the two main divisions of the pelvic cavity?

Answer 1

The pelvic cavity is divided into the false pelvis (above the pelvic brim) and the true pelvis (below the pelvic brim).

Question 2

Which two triangles form the perineum?

Answer 2

The perineum is divided into the urogenital triangle (anterior) and the anal triangle (posterior).

Question 3

What is the main nerve supplying the perineum?

Answer 3

The pudendal nerve is the main nerve supplying the perineum, controlling the external urethral and anal sphincters.

Question 4

Name the muscles that form the pelvic floor.

Answer 4

The pelvic floor is formed by the levator ani group (pubococcygeus, puborectalis, iliococcygeus) and the coccygeus muscle.

Question 5

What are the main branches of the internal iliac artery?

Answer 5

The main branches of the internal iliac artery include the superior gluteal, inferior gluteal, internal pudendal, obturator, and umbilical arteries.

Question 6

Which structure in the male pelvis surrounds the urethra and can be a site of cancer or enlargement?

Answer 6

The prostate gland surrounds the urethra in the male pelvis and can be a site of cancer or benign prostatic hyperplasia.

Question 7

What role does the pelvic splanchnic nerve play?

Answer 7

The pelvic splanchnic nerves carry parasympathetic fibers to the pelvic organs, controlling functions like urination, defecation, and sexual arousal.

Question 8

What is the significance of the ischial spine in clinical practice?

Answer 8

The ischial spine is a landmark for administering a pudendal nerve block during childbirth.

Question 9

What are the potential consequences of pelvic floor muscle weakness?

Answer 9

Weakness in the pelvic floor muscles can lead to pelvic organ prolapse, urinary incontinence, and fecal incontinence.

Question 10

What is the difference between male and female bony inlet?

Question 11

What are the ligaments in the pelvis

Question 12

What are the male internal genital organ in the pelvic girdle

Answer 12

Question 13

What is the arterial blood supply of the prostrate

Answer 13

Question 13

What are the histological division of the prostate

Answer 13

Question 14

How do we divide the broad ligament?

Question 14

What is the venous blood supply of the pastorate

Question 15

Identify the structures that form the boundaries of the pelvic inlet and outlet.

Answer 15

Question 16

What are the boundaries of the perineum?

Answer 16

Anterior: Pubic symphysis
Posterior: Coccyx
Lateral: Ischial tuberosities
Anterolateral: Ischiopubic rami
Posterolateral: Sacrotuberous ligaments

Question 17

What is the perineal body and its significance?

Answer 17

Perineal Body: A fibromuscular mass located at the center of the perineum.
Significance: Serves as an attachment point for perineal muscles, providing structural support to the pelvic floor.

Question 18

Differentiate between the urogenital triangle and the anal triangle.

Answer 18

Urogenital Triangle: Contains external genitalia and the openings of the urethra and vagina (in females).
Anal Triangle: Contains the anus and ischioanal fossae.

Question 19

What structures are found in the deep perineal pouch?

Answer 19

In males: Membranous urethra, deep transverse perineal muscles, bulbourethral glands, and neurovascular structures.
In females: Part of the urethra, deep transverse perineal muscles, and neurovascular structures.

Question 20

What is the role of the ischioanal fossa?

Answer 20

Role: Provides space for the expansion of the anal canal during defecation and contains fat, inferior rectal vessels, and nerves.

Question 21

What is the pelvic diaphragm, and what muscles compose it?

Answer 21

Pelvic Diaphragm: The muscular floor of the pelvis that supports the pelvic organs.
Muscles:
Levator ani (composed of the pubococcygeus, puborectalis, and iliococcygeus)
Coccygeus

Question 22

What are the functions of the levator ani muscles?

Answer 22

Supports pelvic viscera
Maintains continence by reinforcing the external anal sphincter
Helps in childbirth by resisting increased intra-abdominal pressure

Question 23

What is the significance of the ischioanal fossae?

Answer 23

Significance: Provides a cushion of fat that allows for the expansion of the anal canal during defecation. It also contains important structures like the inferior rectal vessels and nerves.

Question 24

Describe the blood supply to the perineum.

Answer 24

Arterial Supply: Internal pudendal artery, which gives rise to several branches, including the inferior rectal artery, perineal artery, and dorsal artery of the penis/clitoris.
Venous Drainage: Internal pudendal veins follow the arteries and drain into the internal iliac veins.

Question 25

What is the clinical significance of the pudendal nerve?

Answer 25

Clinical Significance: The pudendal nerve provides sensory and motor innervation to the perineum. It is essential for continence and sexual function. Damage to this nerve can result in incontinence or sexual dysfunction.

Question 26

What is the urogenital diaphragm, and what are its components?

Answer 26

Urogenital Diaphragm: A triangular muscular layer that spans the area between the ischiopubic rami.
Components:
Deep transverse perineal muscle
Sphincter urethrae
Perineal membrane

Question 27

Explain the pathway of the internal pudendal artery.

Answer 27

Pathway:
Originates from the internal iliac artery.
Exits the pelvis via the greater sciatic foramen.
Re-enters the perineum through the lesser sciatic foramen.
Travels in the pudendal canal and supplies the perineum.

Question 28

What are the coverings of the testis?

Answer 28