#Tuberculous Disease# is usually met with in young adults, and is more common in the right shoulder. The prominent features are pain, rigidity, and wasting of the deltoid and scapular muscles. The pain is sometimes severe, shooting down the arm and interfering with sleep, and it may be associated with tenderness on pressure over the upper end of the humerus. In cases with carious destruction of the articular surfaces there are starting pains, and the arm is shortened. If a cold abscess forms in the bursa underneath the deltoid, the pus may burrow and appear at the anterior or posterior boundary of the axilla or in the axillary space. Pus formed in the joint tends to gravitate along the inter-tubercular groove. The axillary glands may be infected. The primary lesion is either a caseating focus in one of the bones--most often in the upper end of the humerus--or it is of the nature of caries sicca. The greater part of the head may disappear, and the upper end of the shaft be drawn against the socket. In exceptional cases, portions of the glenoid or humerus are found separated as sequestra, or the disease involves parts outside the joint, such as the acromion or coracoid process. Hydrops with melon-seed bodies is rare. In young subjects, destruction of the tissues at the ossifying junction may result in considerable shortening of the arm. The _diagnosis_ is to be made from (1) arthritis deformans, in which the movements are less restricted, and are attended with grating and cracking; (2) paralysis involving the deltoid and scapular muscles--by the absence of pain, and the flail-like character of the movements; (3) disease in the sub-deltoid bursa--by the absence of rigidity and other evidence of implication of the articular surfaces; and (4) sarcoma of the upper end of the humerus--by the history of the case, the use of the X-rays or an exploratory incision. Injuries in the region of the upper epiphysis resulting in loss of movement, may, in the absence of a reliable history, be mistaken for tuberculous disease. While the _prognosis_ is favourable on the whole, recovery is usually attended with fibrous ankylosis and incapacity to raise the arm above the level of the shoulder. The disease often progresses slowly, and may last for years.