Inguinal canal

inguinal canal
Front of abdomen, showing surface markings for arteries and inguinal canal. (Inguinal canal is tube at lower left.)
The scrotum. On the left side the cavity of the tunica vaginalis has been opened; on the right side only the layers superficial to the Cremaster have been removed. (Right inguinal canal visible at upper left.)
Latin	canalis inguinalis
Gray's	subject #258 1239
MeSH	Inguinal+Canal

The inguinal canal is a passage in the anterior (toward the front of the body) abdominal wall which in men conveys the spermatic cord and in women the round ligament. The inguinal canal is larger and more prominent in men. Each person has two, on the left and right sides of the abdomen.

Site

The inguinal canal is situated just above the medial half of the inguinal ligament. In both sexes the canal also transmits the ilioinguinal nerve.

Length

Approximately 3.75 cm (1.57 inches).

Direction

It is oblique directed inferiorly, anteriorly and medially.

Boundaries

A first-order approximation is to visualize the canal as a cylinder, stretching from the deep inguinal ring to the superficial inguinal ring.^[1]

To help define the boundaries, the canal is often further approximated as a box with six sides. Not including the two rings, the remaining four sides are usually called the "anterior wall", "posterior wall", "roof", and "floor".^[2] These consist of the following:

One way to remember these structures is with the mnemonic "MALT", starting at the top and going counterclockwise:

• M - muscles
• A - aponeuroses (The A in MALT coincides with the position of the wall—anterior. This can be used to remember that the direction of the mnemonic is anticlockwise)
• L - ligaments
• T - transversalis/tendon

Contents

• in males : the spermatic cord^[5] and its coverings + the ilioinguinal nerve.
• in females : the round ligament of the uterus + the ilioinguinal nerve.

The classic description of the contents of spermatic cord in the male are: 3 arteries: artery to vas deferens (or ductus deferens), testicular artery, cremasteric artery 3 fascial layers: external spermatic,internal spermatic,cremastic 3 other vessels: pampiniform plexus, vas deferens (ductus deferens), lymphatics 1 nerve: genital branch of the genitofemoral nerve (L1/2)

The ilioinguinal nerve passes through the superficial ring to descend into the scrotum, but does not formally run through the canal.

Development

During development gonads (ovaries or testes) descend from their starting point on the posterior abdominal wall (para-aortically) and near the kidneys down the abdomen and through the inguinal canal to reach the scrotum. The testis then descends through the abdominal wall into the scrotum, behind the processus vaginalis (which later obliterates). Thus lymphatic spread from a testicular tumour is to the para-aortic nodes first, and not the inguinal nodes.

Disorders

Abdominal contents (potentially including intestine) can be abnormally displaced from the abdominal cavity. Where these contents exit through the inguinal canal the condition is known as an indirect inguinal hernia. This can also cause infertility. This condition is far more common in men than in women, owing to the inguinal canal's small size in women.

A hernia that exits the abdominal cavity directly through the deep layers of the abdominal wall, thereby bypassing the inguinal canal, is known as a direct inguinal hernia.

Additional images

Wikimedia Commons has media related to: Inguinal canal

• 

  The spermatic cord in the inguinal canal.

• 

  Inguinal fossae

See also

• Superficial inguinal ring
• Deep inguinal ring

References

External links

• SUNY Labs 36:01-0102
• Atlas of anatomy at UMich abdo_wall63 - "The Male & Female Inguinal Canal"
• Diagram at nurseminerva.co.uk