The Human Elbow Joint ” Part Two
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.
The tiny joint movements which can occur do not look important enough to influence the ability to use the joint but they can allow a minor stretching of the muscles which extend the wrist as we try to achieve a grip or hold on to something. Lengthening a muscle increases its ability to contract afterwards and enhances its function. If the wrist and finger flexor muscles are going to exert the maximum control and power in gripping then the wrist extensor muscles need to work optimally.
Should the opposing muscle group, the flexors, dominate then the extensor muscle origin can become shortened and tight to a degree, limiting the ability of the extensor muscles to adapt wrist positions for useful holding and gripping. The radial head, normally rotating in its radial ligament, confers the precise positioning required to allow the hand to be placed and used in a huge variety of positions.
Pulling the wrist upwards with the palm pointing down and forearm rotation with elbow bend as the palm faces upwards are the two most common and useful arm functions, repeated countless times every day. The origin of both the sets of muscles which do these activities happens to occur very close on the same area of bone on the outside of the elbow. If this leads to overuse of this area the muscles can become tenser, shortening them and reducing tissue elasticity. A cycle can then occur where the initial stress is overuse, followed by the area becoming tight, then the arm compensating and becoming tighter once again.
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.
Over tight muscles in the extensor origin are opposed by the strength of the gripping and holding applied, in cases causing an overstress to the junction between the bone and the tendon and local tearing of tissues from the bone. As a process this can repeatedly occur, with the initiating stress becoming less and less and the pain results becoming more troublesome and long-lasting. As the small scars continually form they contract and add to the local tightness and so the likelihood of painful stretching. Tennis elbow pain can be very severe so that it interferes with activities of daily living.
Jonathan Blood Smyth, editor of the Physiotherapy Site, writes articles about Physiotherapists, physiotherapy, physiotherapists in Solihull, back pain, orthopaedic conditions, neck pain and injury management. Jonathan is a superintendant physiotherapist at an NHS hospital in the South-West of the UK.