Spermatic cord is a cord-like collection of structures that pass through the inguinal canal to and from the testis. The contents of the cord are covered with three concentric layers of fascia derived from the layers of the anterior abdominal wall. The spermatic cord begins at the deep inguinal ring and ends at the testis.
Contents of spermatic cord:
Spermatic cord consists of the following structures.
- Vas deferens (Ductus deferens):
It is a cord like structure that can be palpated in the upper part of the scrotum. It is in fact a thick walled muscular duct. The primary function of this duct is to transport spermatozoa from epididymis to urethra.
- Testicular artery:
It is a branch of abdominal aorta arising at the level of second lumbar vertebra. It is long and slender in form and descends on the posterior abdominal wall. The testicular artery supplies blood to testis and epididymis.
- Testicular veins (Pampiniform plexus):
From the posterior border of testis, an extensive venous plexus, known as the Pampiniform plexus, enters the spermatic cord. It becomes reduced in size as it ascends. At the level of deep inguinal ring, only a single vein is left. This vein is known as testicular vein. It runs along the posterior abdominal wall and drains into the left renal vein on the left side and into the inferior vena cava on the right side.
- Testicular lymph vessels:
These lymph vessels ascend through the inguinal canal and pass up over the posterior abdominal wall to reach the lumbar (para-aortic) lymph nodes. These lymph nodes lie on the sides of aorta at the level of first lumbar vertebra.
- Autonomic nerves:
Sympathetic nervous fibers reach the testis with the testicular artery from the renal or aortic sympathetic plexuses. Afferent sensory nerves accompany the sympathetic fibers.
- Processus vaginalis:
Processus vaginalis is an embryonic developmental outpouching of the peritoneum. The remains of it are present within the spermatic cord.
- Other structures:
In addition to the above prominent structures, there are a few others.
- Cremasteric artery: It is a small branch of the inferior epigastric artery. It supplies the cremasteric fascia.
- Artery to vas deferens: It is also a small artery and arises from the inferior vesical artery.
- Genital branch of genitofemoral nerve: It supplies the cremaster muscle.
Coverings of spermatic cord:
Spermatic cord is covered by three concentric layers of fasciae, derived from the layers of anterior abdominal wall. Developmentally, each covering is acquired as the processus vaginalis descends into the scrotum through the layers of the abdominal wall. The layers are:
- External spermatic fascia: It is derived from the external oblique muscle. It attaches to the margins of superficial inguinal ring.
- Cremasteric fascia: It is derived from the internal oblique muscle. It covers the cremaster muscle.
- Internal spermatic fascia: It is derived from the fascia transversalis (fascia covering the transversus abdominis muscle). It is attached to the margins of the deep inguinal ring.
Clinical significance of spermatic cord:
Spermatic cord is sensitive to torsion. The testicle is prone to rotate within its sac and can kink off its own blood supply. The torsion of spermatic cord may result in irreversible damage to the testicle within hours.
Spermatic cord is also involved in indirect inguinal hernia. In this condition, the contents of the abdominal cavity protrude into the spermatic cord.