The Shoulder Joint is often the seat of trauma, and, especially at clinics attended by manual workers, many such cases are found, generally contusions and dislocations.

Contusions usually affect the anterior and external part of the shoulder, and one can then feel obvious circumscribed muscular swellings in Deltoid, sometimes even small haematomata. Sprains are more uncommon than dislocations. Of the latter the subspinous is rare and the subclavicular rather uncommon. The subcoracoid and subglenoid dislocations are together more numerous than all other dislocations in the body put together. The most common fracture is that of the surgical neck.

Metastatic and other non-traumatic joint affections are comparatively rare, although cases of fluid, chronic progressive arthritis, bacterial inflammation, deforming processes, and gout do occasionally occur. Tuberculosis is rare.

Nervous contractures at the humero-scapular joint of central origin or due to affections of the brachial plexus are rare.

In examination of these eases the exclusion of fracture presents more difficulty than usual. The uncommon fractures of the acromion, of the spine of the scapula, and the tip of the coracoid process (tenderness on pressure) are easy to detect, nor should the neighbouring fracture of the clavicle present any difficulties. The common fracture of the surgical neck of the humerus should not be missed in a fairly careful examination. Fractures of the anatomical neck and impacted fractures near the joint, on the other hand, are more difficult to diagnose, and fractures of the tuberosities immediately outside the joint are often overlooked. Fractures of the lesser tuberosity are certainly rare, but, on the other hand, it is not at all unusual for the whole of the greater tuberosity or the part round its anterior facet, where Supraspinatus is inserted, to be detached. It is not to be expected that palpation can give any decided information here. In such cases considerable swelling both in the transverse and sagittal directions is common. A circumscribed tenderness on pressure often gives the right clue. When the whole of the greater tuberosity is separated it can be felt under the acromion, and is pulled strongly outward, even somewhat backward, while the head of the humerus is dragged inward and can be felt close to the coracoid process. If one suspects that the anterior facet is torn off, this suspicion is increased if when the patient's arm has been abducted to the horizontal position he feels a sharp localised burning pain in the joint when he tries to hold his arm up by his own innervation. Rotation is also painful.

A good skiagram is highly desirable in these cases. If fracture is present massage should not be begun before the joint has been properly fixed for at least a fortnight.

The most marked swellings caused by effusion in the joint are to the front and still more to the back below Deltoid, less in the axilla. In these cases rotation is limited, but the arm is rotated somewhat inward. If the outline of the shoulder bulges outward it is generally the result of a swollen subdeltoid bursa, sometimes of fluid in the joint. If there is a swelling of the acromial bursa it shows more to the front under Deltoid. A swelling in the bursae of Grube can be seen near the coracoid process. Abscesses in the connective tissue or in the lymphatics of the axilla must not be mistaken for inflammation of the shoulder joint and massaged.

It must be remembered in regard to non-traumatic inflammatory affections of the shoulder, especially of bacterial origin, that they often develop so insidiously that functional disturbances have often reached an advanced stage when the patient conies under treatment. I have seen many such cases, especially after the recent epidemics of influenza. The patient has felt a dull pain in the joint which he has put down to ordinary rheumatism, and which has made him, partly unconsciously, perform the movement of abduction as far as possible by rotation of the shoulder blade and, especially if the left arm were the one affected, use the other arm in place of the affected one.

In examination of movements in the humero-scapular joint it is important to distinguish clearly between those movements which take place in this joint and those which take place by means of rotation of the scapula on its antero-posterior axis. One stands behind the patient, grasping the lower angle of the scapula with one hand, and with the other grasps his elbow and performs abduction in the shoulder joint. Normally, as we know, abduction can take place to a horizontal position, but anything further than this is effected, even normally, by rotation of the scapula. When there is any inflammation in or round the joint the patient can easily fix the humerus at the shoulder joint by innervating his muscles, and on examination one gains the impression that mobility is reduced to its minimum or is completely lost. In such cases, especially in the case of the shoulder joint, great diagnostic, prognostic, and therapeutic advantages are to be gained from the use of anaesthetics, and their use should not be neglected. A novice often marvels at the great ease with which movement is obtained without perceptible resistance within a large part, if not the whole, of the normal range. In other cases one can certainly feel how one stretches the shrivelled capsule, or tears asunder adhesions in its lowest part, when one slowly but firmly brings the upper arm up to the head.

The treatment of the shoulder joint is partly dictated by the tendency of the shoulder muscles to atrophic shortening. As soon as it is possible to perform passive movements - a few days after contusions, sprains, the reduction of dislocations, and as soon as the first stage of the healing of a fracture has taken place - one must endeavour before all else to bring the arm both forward-upward and outward-upward to a position behind the head. Every patient with inflammation of the shoulder, of whatever kind this may be, is in great danger of losing this part of the normal mobility of the joint. The corresponding contraction develops quickly and easily for two reasons. One reason is the already-mentioned tendency of some of the muscles concerned, especially Teres Major and Teres Minor, rapidly to undergo atrophic shortening. The other reason is the adhesive synovitis which in the shoulder joint causes adhesions of the folds in the lower part of the capsule anteriorly and posteriorly. Owing to the ordinary position of the arm it is the lower part of the capsule which is shortened by shrinking.

In some dislocations the circumflex nerve is injured. The Deltoid is then occasionally paralysed, and sensory symptoms may also arise.

The important movement of raising the upper arm to the side of the head is best performed when the patient is in lying or half-lying position on a plinth. After this movement he may stand and take adduction forward, which is done by carrying his elbow as far as possible towards the pit of the stomach. Lastly, adduction backward is performed by grasping the patient's fully pronated forearm and carrying the elbow backward as near to the spine as possible. If arm-lifting-upward can be performed fully when one leaves off treating the patient, some one in the patient's home can be shown how to carry out the movement, and the patient can practise it himself several times a day by taking the "hanging fundamental position" of Swedish gymnastics as well as he can.

It is after dislocations of the shoulder joint that one most often finds that the dislocation was not reduced soon enough and that it is no longer possible for it to be reduced. The latter may even be the case after two months, in spite of the accounts published of reductions after a year or even longer. In such cases one must try-by means of massage and gymnastics to make the most of the false joint formed, and it is possible, especially in subcoracoid dislocation, to obtain very fair mobility.