The elbow, like most of the bodys joints, exhibits what are called accessory movements, small gliding and sliding movements which occur inside the joint during movement but which cannot be performed independently. These small movements are essential to the function of a joint and are easily disturbed, reduced or lost in injury or long term postural abnormality. The elbow has small, hardly noticeable movements in a sideways direction as the joint gaps slightly under pressure. This small gapping does not contribute greatly to the positions attainable by the wrist or hand but does make a functional contribution.
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.
The muscles of the extensor part of the forearm can become short and tight, especially if the opposing muscles become over strong, restricting their function in being able to hold the wrist in an effective posture for a functional hand grip. The ability of the radial head to rotate freely within its ligamentous strap is also key to permitting the hand to adopt a huge range of potentially required 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 arm is used for many actions and over some time in a bent position so the wrist is extended and the elbow flexed this can cause a mechanical disadvantage as the wrist extensors are slackened off and so can exert less force. A typical activity of this sort is piano playing and use of a computer mouse. If the muscles have to continually try and recover from ongoing posture stresses which persist for a long period they can shorten close to their origin. With time this sets the elbow up for the small event which will be the last straw and alter the achy, annoying problem into an acute, terrible pain.
A common elbow musculoskeletal problem is tennis elbow or lateral epicondylitis. If a person overdoes a physical action they are not accustomed to they can cause acute trauma to the muscular origin and acute pain onset. A slower development of this condition is more typical, with low level problems until suddenly more severe pain results from relatively minor trauma. In tennis itself using the backhand stroke is a particular stressor on the common extensor origin but many other activities can mimic this activity and produce the same painful 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.
