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 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.
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.
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 muscles are over tight and the muscular action forces are pulling the opposite way as we grip or hold something, there may be an overstress of the tendon-bone junction leading to some of the local tissue fibres tearing away from the bone. Once this has occurred and a degree of healing followed, it becomes easier and easier to re-injure the area with less and less physical force. The healing process, involving scar formation, can also cause tightening as it contracts and lead to a further vulnerability to stretch. In serious cases the severity of the pain can be so bad that simple minor actions can be painful and so are avoided.