At what level does the median nerve exit the carpal tunnel and divide into its terminal branches?

Explanation

## Anatomy of Median Nerve Terminal Division ### Course Through the Carpal Tunnel The median nerve enters the carpal tunnel at the wrist and travels through it without dividing. The carpal tunnel is bounded by: - **Anterior:** Flexor retinaculum (transverse carpal ligament) - **Posterior:** Carpal bones - **Contents:** Median nerve + 8 flexor tendons (FDS, FDP, FPL) ### Terminal Division in the Palm **Key Point:** The median nerve exits the carpal tunnel and immediately divides into **recurrent (motor) and digital (sensory) branches in the palm**, typically just distal to the wrist crease. ### Motor and Sensory Branches | Branch | Target Muscles | Sensory Distribution | |--------|----------------|----------------------| | **Recurrent (Thenar)** | Abductor pollicis brevis, Flexor pollicis brevis (superficial head), Opponens pollicis | — | | **Lateral Digital** | — | Lateral 3½ fingers (thumb, index, middle, lateral half of ring) | | **Medial Digital** | — | Medial 1½ fingers (medial half of ring, little finger) | **High-Yield:** The recurrent branch is the FIRST motor branch and is most vulnerable to injury in carpal tunnel syndrome, leading to thenar muscle atrophy. ### Clinical Correlation **Clinical Pearl:** In carpal tunnel syndrome, compression occurs WITHIN the tunnel, but the clinical signs (thenar atrophy, sensory loss) reflect damage to the branches AFTER they exit the tunnel in the palm.