There are two main nerves to the hand: the median and the ulnar nerves. There are also two diseases that cause compression of these nerves: carpal tunnel (see separate information sheet) and cubital tunnel syndromes.
At the back of the elbow is a tight tunnel, The Cubital Tunnel, through which the ulnar nerve pass into the forearm. This is where it is called “the funny bone” as trauma to this will give an electric shock to the hand. The floor of this tunnel is made by the elbow bones and the roof by a tough ligament (Osborne ligament). Cubital tunnel syndrome (CuTS) is when the ulnar nerve is compressed in this tunnel. The ulnar nerve supplies the muscles of the hand that are responsible for the fine precise function of the hand as well as the hand grip. It also provides sensation to the little and half of the ring fingers. The deformity with an ulnar nerve dysfunction is called a “claw hand”.
Symptoms of CuTS are typically pins and needles and tingling or numbness in the above fingers as well as clumsiness of the hand. It is worse when the elbow is bent. In its most severe forms the small muscles in the hand may even be wasted. It can be from a previous broken elbow, lumps in the elbow or just in people who are genetically more susceptible to get CuTS.