MRS - Scrotum

Question 1

What is the scrotum?

Embryological development?

Answer 1

It is a fibromuscular sac located between the penis and the anus. It is dual chambered, forming an expansion of the perineum.

Embryologically, the scrotum is derived from the parited genital swellings. During development, the swellings fuse in the midline - in the adult this fusion is marked as the scrotal raphe. The scrotum is biologically homologous to the labia majora.

Question 2

Contents?

Answer 2

The scrotum contains three major (paired structures):

1) Testis - the site of sperm production
2) Epididymis - situated of the head of each testicle. It functions as a storage resovoir for sperm.
3) Spermatic cord - a collection of muscle fibres, vessels, nerves and ducts that run to and from the testes.

There are also muscle dibres located within the scrotum, The dartos muscle is a sheet of smooth muscle, situated immediately underneath the skin. It acts to help regulate the temperature of the scrotum, by wrinkling the skin - this decreases the surface area, reducing heat loss.

Question 3

Neurovascular supply?

Answer 3

The scrotum receives nearby neurovascular supply from nearby vessels and nerves.

Arterial supply

1) Anterior and posterior scrotal arteries. The anterior artery arises from the external pudendal artery, while the posterior arises from the internal pudendal artery.

Veins follow arteries and drain into the external pudendal vein.

Nervous supply

Cutaneous innervation to the scrotum is supplied via several nerves, according to the topography:
- Anterior and anterolateral aspect - anterior scrotal fibres derived from the genital branch of the genitofemoral nerve and ilioinguinal nerve.

• Posterior aspect - posterior scrotal nerves derived from the perineal branches of the pudendal nerve and posterior femoral cutaneous nerve.

Question 4

Lymphatics`

Answer 4

Drains into the superficial inguinal nodes.

Question 5

Clinical relevance - haematoma of the scrotum

Answer 5

This may develop as a result of scrotal surgery or trauma in the genital region.

This results in swelling (oedema) and discolouration of the scrotal skin. Occasionally the origin of bleeding may not arise from the scrotal contents (i.e. spermatic cord and testis) but from the basal part of the penile urethra (bulbar urethra) as in ‘straddle injuries’ - direct perineal trauma like when falling onto a bicycle crossbar.