ICD-11

Damage to a single nerve or nerve group of the upper limb (not including central nervous structures such as the brain, brainstem or spinal cord), resulting in a loss of movement, sensation and/or autonomic function.

Upper limb mononeuropathy refers to pathology affecting a single peripheral nerve of the upper limb. The peripheral nerve may be damaged anywhere along its course from the spinal nerve root, as part of the brachial plexus, or along its terminal branches. Damage results in weakness, disturbance of sensation, and/or pain. Generally, the term mononeuropathy refers to nerve damage occurring distal to the brachial plexus. There are many nerves in the arm distal to the brachial plexus; therefore, different mononeuropathies can occur. The most common mononeuropathies of the upper extremity are carpal tunnel syndrome, ulnar neuropathy, and radial neuropathy. These are often due to mechanical injury caused by compression or trauma. Most commonly, this can be seen in the median nerve at the wrist (carpal tunnel syndrome) or in the ulnar nerve at the elbow. Trauma is the most frequent cause of radial neuropathy, although this can also occur from compression over the spiral groove (Saturday night palsy). Diabetes mellitus, connective tissue disorders, and infections such as leprosy are some of the diseases considered in the aetiology of mononeuropathy.