_Treatment._--The limb should be immobilised in the position of abduction with the forearm and hand directed forwards; the most efficient apparatus is a plaster spica embracing the thorax and the upper limb down as far as the wrist. If the articular surfaces are affected and the disease is likely to lead to ankylosis, the arm should be abducted to a right angle. The severe pain of caries sicca may be relieved by blistering or by the application of the cautery. To inject iodoform, the needle is introduced either immediately outside the coracoid process, or just below the junction of the acromion process and spine of the scapula. When the disease does not yield to conservative measures, or the X-rays show a gross lesion in the bone, excision of the joint should be performed; a close fibrous ankylosis usually results, and the arm is quite a useful one provided the abducted position has been maintained throughout. #Pyogenic Diseases.#--The shoulder-joint may be infected by extension of suppurative osteomyelitis from the upper end of the humerus, or from suppuration in the axilla, or through the blood stream by ordinary pus organisms, pneumococci, typhoid bacilli, or gonococci. Extension should be applied to the arm abducted at a right angle. When it is necessary to open the joint, the incision should be placed anteriorly in the line of the inter-tubercular groove; if a counter-opening is required it is made on the posterior aspect by cutting on the point of a dressing forceps introduced through the anterior incision. #Arthritis Deformans.#--The shoulder is seldom affected alone, except when the arthritis is a sequel to injury, such as a fracture of the neck of the humerus. The common type of lesion is a dry arthritis with fibrillation and eburnation of the articular surfaces. The long tendon of the biceps is usually destroyed, the head of the bone is drawn upwards, and, after wearing through the capsule, rubs on the under surface of the acromion, which also becomes eburnated. The clinical features are pain, stiffness, and cracking on movement, and as these symptoms may also be caused by loose bodies in the joint, an X-ray picture should be taken to differentiate between them. #Neuro-arthropathies# of the shoulder are met with chiefly in syringomyelia. In some cases there is a large fluctuating and painless swelling; in others marked and rapid wasting of the deltoid and scapular muscles with flail-like movements of the joint associated with disappearance of the upper end of the humerus (Fig. 104). [Illustration: FIG. 103.--Arthropathy of Shoulder in Syringomyelia. The upper end of the humerus has disappeared and the movements are flail-like (cf. Fig. 104).] [Illustration: FIG. 104.--Radiogram of specimen of Arthropathy of Shoulder in Syringomyelia. The head of the humerus has disappeared and masses of new bone have formed in the surrounding muscles (cf. Fig. 103).]