My musician son has damaged both his wrists. The first symptoms were waking in the morning with "dead" arms, but recently while lifting a very heavy box with two thin handles he put his wrists under great strain. Now he can barely lift anything without terrible pain and cannot twist a jam-jar lid, play bass or use a computer. He has tried different wristguards and a ball mouse with with limited results. Is there any light at the end of the tunnel?

It is always difficult to put forward a diagnosis without examining the patient, especially when the symptoms are relayed by a third person. Overuse may play a role: musicians practise for long hours, and are to be considered top-level athletes in full-time training. The same rules of diagnosis and management used in athletes apply. Musicians may suffer from focal dystonia, a condition characterised by a loss in motor control of one or more fingers, and muscles in the hand and forearm tense and tighten. Professional musicians are most affected by this condition, given the repetitive movement of the fingers over a significant period of time. Focal dystonia can easily be misdiagnosed as simple overuse or stress of the hand. Although not obvious, the level at which the problem is caused is not the hand, but the brain: its capacity to control movement is impaired. Muscles may tighten up involuntarily, awkward movements may be produced, the fingers may not respond to commands from the brain, or respond in involuntary ways. The stress and frustration endured are immense. Recently, injections of botulinum in the affected muscles have been tried, but retraining seems to have the best chance of success. Other causes of the symptoms reported by your son can lie in carpal tunnel syndrome or, less likely, in some of the vessel entrapment syndromes of the upper limb. Carpal tunnel syndrome is due to compression of the median nerve at the wrist, and can be either of an unknown cause, or a consequence of a systemic condition, such as hypothyroidism. In any case, I would strongly advise seeking your GP's opinion.

I am 63 and an active mountaineer. Over the past few years I have developed serious sporadic pain between the third and fourth toes of my left foot. This can be triggered by any mild constriction of the foot or by putting serious pressure on it. I am told that it is due to a Morton's neuroma and have been supplied with two orthotics, neither of which has had any positive impact. What further steps could I discuss with my consultant?

Your symptoms do suggest a Morton's neuroma, an enlarged nerve in the space between the third and fourth toes. Part of the nerve from the outer side of the toes combines with part of the nerve from the inner side. Above the nerve is the metatarsal ligament, with very little room in between: with each step, the ground pushes up on the enlarged nerve, and the ligament pushes it down, with compression in a confined space. The syndrome is more common in women, possibly because they wear tight shoes with high heels. The diagnosis is generally made through clinical examination, and radio-graphs are taken to exclude a fracture, tumours, and arthritis. An ultrasound scan can detect whether the symptoms are really coming from a Morton's neuroma, or from an inflammation of the fluid collection under the joints of the toes (bursitis). Patients benefit from wearing wider shoes, and from padding, taping or orthotics to relieve the area around the neuroma. An injection of local anaesthetic and a corticosteroid to reduce inflammation and pain may also help. If these measures do not work, surgery may offer a solution. The "classical" operation involves making an incision on the top or on the sole of the foot. The metatarsal ligament is cut, and the enlarged portion of the nerve resected. This relieves the pain, but causes loss of sensation over the third and fourth toes. Using a different, minimally invasive approach, the ligament is sectioned through small incisions skin, and the nerve is left intact.

· Professor Maffulli is a consultant orthopaedic and sports injury surgeon. To ask him a question email fitness@theguardian.com.