The ulnar nerve in the tunnel of Guyon

The ulnar nerve (C8, T1) of the upper limb innervates the forearm and palm. In its course it is subject to entrapment / lesion at bottleneck sites. Among the more distal ones is the compression / injury to the nerve at the wrist – where its deep branch traverses an osseo-ligamentous canal, referred to as Guyon’s tunnel. As the nerve supplies many ‘educated’ intrinsic muscles of the palm associated with manually dexterous actions, lesions to the nerve often lead to a major loss of functional efficiency of the hand. Ulnar nerve injuries are claimed to be the biggest cause to loss to the number of man-days in the industrial sector. This study examines the more distal anatomical relations of the nerve and lists the locales of the branches given off by the nerve and the sites of possible compression along its carpal route. Key words: ulnar nerve, Guyon’s tunnel, compression syndromes, lesions