Superficial inguinal ring

The superficial inguinal ring is a triangular opening in the aponeurosis of the external oblique muscle located immediately superior and lateral to the pubic tubercle. It represents the external opening of the inguinal canal and allows structures traversing the canal to emerge into the superficial tissues of the groin.

Boundaries of superficial inguinal ring

The margins of the superficial inguinal ring are formed by two tendinous crura of the external oblique aponeurosis. The medial crus attaches to the pubic symphysis, while the lateral crus attaches to the pubic tubercle. These crura are connected by curved intercrural fibres, which help prevent excessive widening of the ring during increases in intraabdominal pressure. The base of the superficial inguinal ring lies superior to the pubic crest and forms the exit of the obliquely oriented inguinal canal.

--- Reflected inguinal ligament

The reflected inguinal ligament (Colles ligament) arises partly from the medial crus of the ring and contributes to reinforcement of the lower anterior abdominal wall.

Structures passing through superficial inguinal ring

In males, the spermatic cord exits through the superficial inguinal ring, while in females the round ligament of the uterus passes through it. The ilioinguinal nerve also emerges through the ring in both sexes.

The ring is normally narrow and slit-like, helping maintain the integrity of the abdominal wall while permitting passage of cord structures.

Clinical correlates

Clinically, the superficial inguinal ring is important in the assessment of inguinal hernias. In indirect inguinal hernias, abdominal contents pass through the deep inguinal ring, traverse the inguinal canal, and may emerge through the superficial inguinal ring into the scrotum or labia majora. Enlargement or weakness of the ring may predispose to herniation.