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 small movements may not look like they contribute much to the function of the elbow joint but they can. As we adjust the arm to grip something effectively the added movements of the elbow allow a slight lengthening of the wrist extensor muscles at times. A small amount of tension on a muscle enhances its ability to contract and increases its effectiveness, in this case the extending of the wrist so that the hand is in the right position for the strength of the grip to be applied.
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 dominant movement patterns we perform again and again every day for hundreds of repetitions typically are turning the forearm over so the hand is palm up and pulling the wrist back with the palm down. Both the main muscles which are concerned with these very common actions originate from the same anatomical location on the outside of the forearm near the elbow. Overuse of these muscle groups can lead to increased tone in this lateral compartment of the elbow, causing shortening and loss of elasticity of the tissues. A cycle of tightening, muscular compensation and further tightening can develop.
Elbow problems can be particularly brought on by using the arm for long periods with the wrist extended and the elbow bent, as the bent elbow slackens off the wrist extensors slightly and decreases their ability to be effective. This type of activity is especially apparent in playing the piano or using a computer mouse. Repetitive activity over a long time can cause more permanent shortening of the muscles as they try and recover from continuous postural trauma. This allows a small activity at some time to cause local trauma and convert a troublesome, achy problem into an acute and very painful injury.
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.
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