Carpal tunnel syndrome is one of the most commonly diagnosed disorders of the upper extremity. The etiology of the neuropathy is known to be associated with many disorders, with the etiology of carpal tunnel syndrome mainly attributable to ischemia of the median nerve. The purpose of this study was to determine the presence of neural elements within the transverse carpal ligament. Fourteen transverse carpal ligaments were harvested from seven male and seven female fresh frozen cadavers with an average age of 76 years. The tissues were stained with S-100 using a standard immunoperoxidase technique used to localize neural tissue. The transverse carpal ligament consisted of interwoven bundles of fibrous connective tissue. It was found to have an intraligamentous and extraligamentous neural network consisting mostly of free nerve endings and pacinian corpuscles. Ruffini's corpuscles were not identified. This study showed that there is neural innervation to the transverse carpal ligament. Pacinian corpuscles have been shown to be mechanoreceptors which respond to changes in joint position, whereas free nerve endings have been identified as nociceptors. Neural innervation were present in the transverse carpal ligament, and the nociceptive information relayed by these neural elements may contribute to the pain associated with carpal tunnel syndrome. In addition to being a mechanical wrist stabilizer, the transverse carpal ligament also may play a role in proprioception of the wrist.

Endoscopic carpal tunnel release has been shown to decrease postoperative recovery time in patients undergoing surgery for carpal tunnel syndrome. There is, however, some controversy concerning the safety and reliability of the procedure. We performed endoscopic carpal tunnel release utilizing the two portal technique described by Chow on 20 fresh cadaver specimens. There were no injuries noted in any of the vital structures including the ulnar artery, superficial palmar arch, third common digital nerve or flexor tendons. The transverse carpal ligament was found to be completely transected in 95% of the specimens. Hyperextension of the wrist significantly displaces the vital structures both dorsally and distally. The use of a slotted cannula and specially designed blades protect the surrounding structures during the procedure. Based on this study, endoscopic carpal tunnel release using the technique described by Chow may be performed reliably without injury to any of the vital structures.