Curriculum · Surgery
Inguinal canal anatomy and hernia type
What it is
The inguinal canal is a 4 cm oblique passage in the lower anterior abdominal wall, extending from the deep inguinal ring to the superficial inguinal ring. Identifying its layers is critical during repair, because each wall answers a different question.
- Deep, or internal, ring: an opening in the transversalis fascia, just above the mid-inguinal point and lateral to the inferior epigastric vessels. Indirect hernias enter here.
- Superficial, or external, ring: a triangular gap in the external oblique aponeurosis above the pubic tubercle, the palpable exit of the canal.
- Posterior wall: transversalis fascia, reinforced medially by the conjoint tendon, which is the fusion of internal oblique and transversus abdominis. Weakness here gives a direct hernia.
- Roof: internal oblique and transversus abdominis, which matter in posterior reinforcement.
- Floor: inguinal ligament and lacunar ligament, the boundary for the femoral canal.
In males the canal carries the spermatic cord: vas deferens, testicular artery, pampiniform plexus and the genital branch of the genitofemoral nerve. Injury there can end in infertility or hematoma. In females it carries the round ligament of the uterus, where hernias are less common but the same landmarks apply.