 As might be expected, the symptoms involve weakness in the muscle innervated by the AIN including the flexor digitorum profundus muscle to the index (and sometimes the middle) finger, the flexor pollicis longus muscle to the thumb and the pronator quadratus of the distal forearm.As opposed to carpal tunnel syndrome, the AIN has no sensory fibers and therefore no numbness associated with the Anterior Interosseous Syndrome.Non-surgical treatment consists of splinting, proximal tissue massage and anti-inflammatory drugs.