GI Radiology > Hernia > Anatomy


Knowledge of the anatomy of the inguinal region facilitates understanding of inguinal hernias.

Internal View

The image at right is an internal view of the anterior abdominal wall showing the internal ring, the inferior epigastric vessels and Hesselbach’s triangle. Inguinal hernias are defined by their relation to the inguinal (Poupart's) ligament and Hasselbach's Triangle, an area bordered laterally by the inferior epigastric artery, inferiorly by the inguinal ligament, and medially by the lateral margin of the rectus sheath. The floor is formed by the transversalis fascia. Spigelian hernias occur between the internal oblique and transversus abdominis muscles. Direct inguinal hernias pass medially to the inferior epigastic vessels, while indirect inguinal hernias pass laterally to the inferior epigastric vessels.
Internal view of the anterior abdominal wall

External View

This external view of the lower abdominal wall shows the spermatic cord exiting the external inguinal ring and the dissection of the muscular layers of the wall: the external oblique, internal oblique and transversus abdominis. The transversus abdominis layer is key to the formation of hernias and to surgical repair. The transversalis fascia forms the internal investing layer of the rectus muscle and has little inherent strength for protection from hernia or usage for repair. Hesselbach’s triangle (H) again lies medial to the epigastric vessels. In men, the spermatic cord passes through the inguinal canal from the internal inguinal ring (transversalis fascia) to the external inguinal ring (external oblique aponeurosis).
External view of the lower abdominal wall

CT anatomy

Four CT images illustrate the normal anatomy of the inguinal region of a male pelvis. The inguinal ligament is difficult to identify on CT due to its oblique course and thin diameter.

The inferior epigastric artery and vein (IE) lie anterior to the external iliac vessels (E) just lateral and posterior to the rectus abdominis.The testicular vessels (TV) are seen posterior to the inferior epigastric vessels near the inguinal canal.
The spermatic cord is in the inguinal canal at the internal ring.The spermatic cord is lateral to the base of the penis in this section distal to the external ring.

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