Distal rupture of the palmaris longus tendon and fascia as a cause of acute carpal tunnel syndrome.

Acute carpal tunnel syndrome is rare compared with its more chronic presentation. Previous reports in the literature have documented the most common causes. Rupture of the distal palmaris longus tendon into the palmaris fascia as a cause of an acute carpal tunnel syndrome has not been reported previous to this case report. Partial rupture of the tendon and hemorrhage around its insertion produced intrinsic compression on the transverse ligament and the underlying nerve.