Palmar carpal ligament

The palmar carpal ligament is a superficial, transverse fibrous band, representing a localized thickening of the antebrachial fascia on the volar (palmar) aspect of the wrist.

It is crucial to distinguish this ligament from the flexor retinaculum (transverse carpal ligament). The palmar carpal ligament lies superficial and proximal to the flexor retinaculum, which, while also a thickening of deep fascia, is located distally and forms the roof of the carpal tunnel.

The palmar carpal ligament primarily functions as the roof of Guyon's canal (ulnar canal). This canal facilitates the passage of the ulnar nerve and ulnar artery into the hand, lying superficial to the flexor retinaculum (but deep to the palmar carpal ligament). In addition, the ligament also helps to stabilize the wrist and prevents bowstringing of the long extensor tendons.