The arm is most commonly injured in a fall when it is used to protect the head and face as well as cushion the fall. Never forget to check ABC (see page 94) for injuries elsewhere in the body, and distal neurovascular status. In high energy accidents (such as falls from a motorcycle) the brachial plexus may be torn. This is a devastating injury often leaving a useless arm and very severe causalgia-type pain.

Conversely the clavicle is only a thin strut holding the shoulder complex out and away from the midline. It is therefore easy to break. However, it also heals quickly and has great powers of remodelling if there is a malunion. The joints at each end, especially the acromioclavicular joint, can also be subluxed or even dislocated.

The shoulder joint itself allows a large range of movement and as a result is prone to dislocation. This is almost always anterior. The patient has frequently had the problem before and will tell you exactly what the diagnosis is, and even how it can be reduced quickly. Reduction is relatively simple immediately after the injury (the arm just needs to be pulled straight). Later, once muscle spasm has set in, strong analgesia or even an anaesthetic may be needed to get the shoulder back into joint. Treatment is then gentle mobilisation while waiting for the torn tissues around the shoulder joint to heal. If dislocations are repeated, surgery to repair the soft tissues around the shoulder may be needed.

Any patient who has had a dislocation of the shoulder is liable to another. If the arm is put into the position in which the dislocation can occur (above their head and forced backwards) they will become very worried about what might happen next. This is known as an ‘apprehension sign