Abdomen

Inguinal Canal

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Overview

The inguinal canal provides a conduit, which enables the spermatic cord and round ligament to pass from intra- to extraperitoneal, and onto the external genitalia. The inguinal canal is a site of particular anatomical importance due to the frequency of inguinal hernias in clinical practice. 

Gross Anatomy

The inguinal canal is a tubular structure passing from the anterior superior iliac spine to the pubic tubercle. It is comprised of a deep ring, which is where there is direct communication with the peritoneal cavity, and the superficial ring. The landmark of the deep ring is halfway along the length of the inguinal canal, commonly known as the mid-point of the inguinal canal. The superficial ring is just superior to the pubic tubercle, marking the end of the inguinal canal.

Clinical Anatomy

Inguinal hernias

 

Inguinal hernias occur when intraperitoneal contents escape through a weakness in the inguinal canal. Indirect hernias come through the deep ring and direct hernias come through the posterior wall of the inguinal canal (i.e. transversalis) in Hasselbach’s triangle (see below).

 

They are diagnosed clinically as a lump in the groin, although an US scan can confirm the diagnosis (not often performed in practice, especially if it is clinically obvious). The treatment is surgical repair. There are two main methods, open or laparoscopic. They have similar outcomes, although the post-operative recovery time with laparoscopic repair is slightly shorter. The open repair performed in common practice is known as the modified Lichtenstein repair. The recommended repair of bilateral inguinal herniae is via the laparoscopic route. They are reduced and then reinforced with mesh to reduce the risk of recurrence. 

Quick Anatomy

Key Facts

Inguinal canal

 

Anterior

External oblique aponeurosis with internal oblique laterally

Posterior

Transversalis fascia

Roof

Internal oblique, transversalis fascia and fibres of transversus abdominis

Floor

Inguinal ligament (thickened fibres of external oblique); medially, the lacunar ligament

Hasselbach’s triangle

 

Medial

Lateral edge of rectus sheath (linea semilunaris)

Lateral

Inferior epigastric vessels

Floor

Inguinal ligament

Aide-Memoire

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Summary

The inguinal canal carries the round ligament and Ilioinguinal nerve in women and the spermatic cord along with the Ilioinguinal nerve in men. It is important to remember the contents of the cord, often remembered as:

 

  • 3 arteries (artery to vas deferens, testicular artery, cremasteric artery);
  • 3 fascia (external spermatic, cremasteric and internal spermatic fasciae);
  • 3 nerves (genital branch of genitofemoral, smypathics and ilioinguinal nerve- note, it is not technically insde the cord);
  • 3 others (pampiniform plexus, lymphatics and the vas deferens)

References

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