Which structure forms the medial boundary of the inguinal canal?

Explanation

## Medial Boundary of the Inguinal Canal **Key Point:** The conjoint tendon (also called the falx inguinalis) forms the medial boundary of the inguinal canal. It is the fused aponeurosis of the internal oblique and transversus abdominis muscles. ### Anatomical Composition The conjoint tendon is formed by: 1. Aponeurosis of the internal oblique muscle 2. Aponeurosis of the transversus abdominis muscle These two layers fuse together and insert onto the pubic crest and pectineal line medially. ### Boundaries of the Inguinal Canal | Boundary | Structure | |----------|----------| | **Medial** | Conjoint tendon (falx inguinalis) | | **Lateral** | Internal ring (lateral to inferior epigastric vessels) | | **Superior** | Internal oblique and transversus abdominis arches | | **Inferior** | Inguinal ligament | | **Anterior** | External oblique aponeurosis | | **Posterior** | Transversalis fascia and peritoneum | **High-Yield:** The conjoint tendon is clinically significant because it forms the floor of the inguinal canal medially. Weakness or deficiency of the conjoint tendon predisposes to direct inguinal hernias, which protrude medial to the inferior epigastric vessels. **Clinical Pearl:** In direct inguinal hernias, the hernia sac protrudes through the floor of the canal (conjoint tendon deficiency) medial to the inferior epigastric vessels, whereas in indirect hernias, the sac passes through the internal ring lateral to these vessels.