Distal median nerve dysfunction occurs when there is damage to the distal portion of the median nerve, which travels down the arm and provides movement and sensation to the thumb. Carpal tunnel syndrome , another form of median nerve dysfunction , is one of the more common peripheral neuropathies. Dysfunction of a single nerve group, such as the distal median nerve, is classed as mononeuropathy . The usual causes are direct trauma, prolonged pressure on the nerve, and compression of the nerve by nearby body structures.
Entrapment involves pressure on the nerve where it passes through a narrow structure.
Wrist fractures may injure the median nerve. In some cases, no detectable cause can be identified. This is a fairly common occupational or recreational injury. There may be weakness of the thumb and difficulty with opposition of the thumb and little finger. A detailed history may be needed to determine the possible cause of the neuropathy.