The large majority of the bodys joints, including the elbow, are capable of producing what are known as accessory movements, small sliding and gliding movements occurring inside a joint which a person cannot perform on their own. Accessory movements are vital for the normal use of a joint and are easily disrupted, limited or abolished by trauma or postural bodily misuse. The elbow accessory movements are very limited in size and consist of a small sideways gapping of the joint, which does not make a large difference to the ability to achieve various positions with the hand but does increase functional ability.
These little accessory movements may not seem to be able to make a difference to the use of the elbow joint but they can permit a slight lengthening of the extensor muscles of the wrist when we are trying to adjust our arm position to get hold of something. If a muscle is stretched slightly this increases the contractibility and thereby its function. In this case the extensor muscles can extend the wrist more successfully to allow the flexor muscles to apply grip strength.
If the opposite muscles dominate and the extensor compartment of the elbow and forearm is tight and shortened to some extent the muscles will not be able to position the wrist well to allow effective grip and holding of objects. The rotatory ability of the radial head within its supporting ligament is also of high importance in allowing the hand to be positioned in virtually any number of positions.
The two commonest and repeated movements we perform again and again throughout the day are extending the wrist with the fingers downwards and rotating the forearm so that the palm faces up. The groups of muscles which perform these two actions start life over the same patch of bone on the outer side of the elbow, leading to potential overuse and pain problems. Overuse of the muscles can increase the tone in the outer elbow compartment, reducing both the elasticity of the tissues and causing them to shorten. This can develop into a cycle of becoming tight, adapting by using the hand in new ways and then tightening further.
If the elbow is bent and the wrist is extended in an activity which is repetitive and lasts for some time then this can be damaging as the elbow bend loosens the extensor muscles a little and reduces their effectiveness to some degree. Examples of this activity are using a computer mouse or playing a piano. Continuous postural stresses from repeated actions over a long period can permanently cause tightening as the muscles continually recover. All this prepares the elbow for a time when a relatively minor added stress changes the typical, irritating achy joint into a highly acute and painful problem.
Tennis elbow is a common condition and typically develops as described above. It can come on acutely out of the blue after someone does an excessive amount of work, stressing the elbow very heavily and causing local injury and inflammation. More commonly there is a slow and longer term development of problems followed by a more sudden acute episode as a sudden stress is applied. Playing the backhand stroke in tennis is a particularly troublesome action to stress the common extensor origin but many other actions can produce the same result.
If the hand and forearm are engaged in strenuous activity gripping or holding an object they may traction the tightened tissues around the extensor origin and damage some of the fibres at the junction between the tendon and the bone. Repetitive cycles of this activity can allow the pain to become gradually worse whilst the precipitating stresses reduce in severity, making the whole pattern more irritable. The continual injury and scarring process which repeats makes the injured areas tighten up further and expose them to the danger of sudden stretching stresses. Often irritating, the pain of tennis elbow can severe.