A shoulder joint is a ball and a socket joint. The head of the upper arm borne (humerus) and a shallow cup-like structure of the shoulder blade scapula) make up this joint. The head is much bigger than the socket and only a part of the head can fit into the socket called the glenoid cavity. The socket is deepened by a fibro-cartilagenous rim. Due to this arrangement, the shoulder has a better range of movement than any other joint in the body. But it is weak joint and depends on the surrounding muscles for its strength.
The joint is covered by a sac-like structure, a fibrous capsule. This capsule is lax and the bones can be separated from each other for a distance upon half an inch. This can provide a further range of movement. The inferior part of the capsule is the weakest part. The movement at the shoulder joint is further increased by the movement of the shoulder blade itself. When the arm is raised upto120 , movement takes place at the shoulder joint and a further 60 is obtained by rotation of the shoulder blade. The acromio-clavicular joint at the lateral end of the collar bone (clavicle) and sterno-clavicular joint at the medial end of the collar bone also participate in shoulder movements.
In the case of a frozen shoulder, the capsule is thickened and retracted. This can be clearly demonstrated by arthography (taking an X-ray after injecting a radio-opaque dye inside the joint). Why a frozen shoulder occurs is not known. There is a limitation of movement in all directions. It generally occurs between the ages of forty to sixty. After sixty, it is rare. The usual course of the disease is as follows:
It starts with an ache in the shoulder when the arm is moved. There is pain when the arm is kept still. After one month the pain is more severe and spreads down to the elbow. It is worse at night and increases further if the patient lies on the same side. Restriction of movement starts becoming obvious. After 2-3 months severe pain occurs at the slightest movement. The patient cannot raise his hand more than thirty to forty degrees. The patient cannot raise his hand more than thirty to forty degrees. The rotative movement of the arm is also limited. After 4 months no further diminution takes place in the movement. The pain is at its worst at the end of 4 months. After 5 months it begins to reduce gradually. After 6 months there is no constant pain. Pain is felt only when the arm is moved. The patient is now able to lie on the painful side. After 7months there is pain only in the upper part of the shoulder. After 8 months the range of movement begins to become wider. After one year the patient is almost well.
It has been noted that the pain and restriction of movement decrease during the first four months. During the next four months the pain decreases but the limitation of movement persists. In the last 4 months the range of movement returns. If exercises are done, the full range of movement is sure to return, and if no exercises are done, some amount of permanent limitation will persist at the shoulder joint. In the severe variety, pain may go on increasing upto nine months. Wasting and thinning of muscles also start and complete recovery may take upto two years.
Some doctors advise forced mobilisation under general anaesthesia. Though some very good results have been achieved by this process, some grave setbacks also occur. This treatment is therefore not advisable because during this act a tear in the lower part of the capsule can occur. This has been seen by arthography taken before and after the treatment. We believe that skill and experience play a dominant role in achieving good results. It is very important to know when to stop and how to grade these manoeuvres. This is practically impossible when the manipulation is done under anaesthesia, because the results are only known the next day or when the patient wakes up. For such cases we recommend a gradual stretching of the shoulder without anaesthesia. However this is not as simple as it sounds. If there is too much stretching, it provokes pain and if there is too little, it does not produce any results. Stretching has to be done with great care. The patient feels great discomfort when the arm reaches the restricted range; it should then be coaxed a little further without increasing the pain or producing a muscle spasm. The shoulder should be moved in this final increased range for five to seven minutes twice a week. The patient should also be taught certain exercises which should be done twice a day at home. This treatment, in my experience, reduces the recovery period to two to three months. Sometimes cervical and upper dorsal manipulation along with mobilisation is helpful.
This treatment can also be given in the case of a frozen shoulder after an accident. There are other cases where the patient feels pain in the shoulder joint, but it is radiated from the neck. In these cases, ‘the shoulder is nothing, the neck is everything!’ Here manipulation of the lower cervical spine brings about a spectacular recovery, and when this is so, the above diagnosis is confirmed. In these cases movement at the shoulder joint is quite free. Pain may radiate in the whole arm from the base to the neck, accompanied by numbness, a tingling sensation and a feeling of pins and needles in the hands.The pain in the shoulder may also be caused by diseases of the thorax abd abdomen.
Keeping the joint mobile is very important. This can be done at home in the following way: