information about

An injury or some traumatic occurrence, perhaps minor, can be the precipitating event which kicks the knee joint into a painful state. Even a small injury can cause the joint to swell and the knee can react in complex and negative ways to the presence of minor levels of fluid in the joint. Trauma causes the synovial lining to secrete synovial fluid and this is contained inside the capsule of the joint, continual movement irritating the joint by stretching of the capsule. A swollen knee is typically held at an angle of about thirty degrees as this is the most comfy, loose position for the joint.

The ankle is a very particular joint, commonly referred to as a mortise joint. It hinges backwards and forwards whilst we are walking and also gives the sideways support to allow us to hold our balance in moving and unstable conditions. The ankle hinge connects the foot to the lower leg and allows transmission of the forces of the bodyweight across it and onto the mobile and propulsive platform of the foot. In the lower leg the tibia makes up most of the upper part of the ankle with the fibula contributing a small amount towards the outside.

The elbow makes up the middle joint of the arm and makes two reasonable length and useful levers of the arm. At first glance the elbow looks like a simple forwards and backwards hinge but on looking more closely it is capable of a lot more. The upper arm bone (humerus) connects in the elbow with the two forearm bones, the ulna and the radius. The upper part of the ulna and the lower part of the humerus form the elbow joint, with the easily felt bony point of the ulna at the back of the joint. The end of the humerus has a rounded cylinder shape which is surrounded partially by the ulnar part of the joint.

The shoulder is a specialised joint which has an extreme range of motion at the connection between the upper limb and the trunk. The joint classification of the shoulder is as one of the ball and socket joints but this structure is much clearer in the hip than the shoulder. The humeral head, the upper end of the arm bone, is a large rounded ball-like structure with some obvious relationship to the ball of the hip. The shoulder socket however is quite different from the hip in that the joint surface is very flat and small compared to the head.

As the individual nerve roots emerge from the neck they join together and separate in a complex fashion in an area called the brachial plexus, running down from the neck to the axilla where the individual arm nerves emerge. Nerves are very vulnerable structures and can be injured in gunshots, direct blows, knife attacks and traction injuries, which involve a sudden stretch. The results can be very disabling, with a chronically painful arm the patient is not able to move or use very well. Recovery is very variable and many patients have to cope with a less than useful arm.