Anterior Interosseous Syndrome

If there is reason to suspect pronator syndrome then differential diagnosis from anterior interosseus syndrome (also known as Kiloh-Nevin syndrome) is to be considered. Here there is compression of the anterior interosseous nerve, which is a branch of the median nerve in the forearm. Should there be the presence of thick fibrous strands in the arm then this part of the nerve can also be damaged. This occasionally occurs spontaneously after a forearm fracture or an infection. Excessive stressing has also been put forward as a possible cause.

Because the clinical picture of this condition can be the inability to flex the thumb at the distal interphalangeal joint, the occasional misdiagnosis is possible (for example a tear to the thumb’s flexor tendon). However, in a compression syndrome of the anterior interosseous nerve, there is additional pain in the forearm and a weakness in the index finger so that a pincer movement with thumb and index finger is difficult or impossible. The patient does not have the ability to form a circle using the thumb and index finger. Should conservative therapy methods not have achieved any noticeable improvement after a maximum of 8 weeks then the nerve should be decompressed through surgery.

Anterior interosseous syndrome is one of the nerve compression syndromes.
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