#Tarso-metatarsal Dislocations.#--One, several, or all of the metatarsals may be separated from the distal row of tarsal bones--the usual cause being a fall from a horse, the foot being fixed in the stirrup. The bases of the metatarsal bones are displaced laterally and towards the dorsum. The base of the second metatarsal and the first cuneiform are sometimes fractured. Reduction by manipulation is generally easy in dorsal dislocations, but may be difficult when the bones are displaced laterally. This may be due to fragments of bone or soft parts getting between the bones, and may necessitate operative interference. In old-standing dislocations, operation is to be advised only when locomotion is seriously interfered with. #Dislocation of the Toes.#--The great toe may be dislocated at its metatarso-phalangeal joint, the base of the proximal phalanx passing towards the dorsum (Fig. 102). Diagnosis and reduction are alike easy. [Illustration: FIG. 102.--Radiogram of Dislocation of Toes. (Sir Montagu Cotterill's case.)] #Inter-phalangeal# dislocations are rare and are easily reduced. CHAPTER IX DISEASES OF INDIVIDUAL JOINTS THE SHOULDER-JOINT The shoulder is seldom the seat of disease, and most affections of the joint are met with in adults. In young subjects, infective processes result chiefly from extension of disease from the upper epiphysial junction of the humerus, which is partly included within the limits of the synovial cavity. The synovial membrane, in addition to lining the capsular ligament, is prolonged down the inter-tubercular (bicipital) groove around the long tendon of the biceps, and pus may escape from the joint by this diverticulum and gravitate down the arm; we have also observed loose bodies of synovial origin in this diverticulum. There is frequently a communication between the joint and the sub-deltoid bursa. There is no attitude characteristic of disease of the shoulder-joint, but the girdle is usually elevated, the upper arm held close to the side and rotated medially, while the elbow is carried a little backwards. In the later stages, the head of the humerus may be drawn upwards and medially towards the coracoid process. Fixation of the shoulder-joint is largely compensated for by movement of the scapula on the thorax, so that when testing for rigidity the scapula should be fixed with one hand while passive movements of the arm are carried out with the other. The deltoid is usually atrophied, allowing the acromion, coracoid, and great tuberosity of the humerus to stand out prominently beneath the skin. Swelling is rarely a prominent feature, except when there is a collection of synovial fluid or of pus in the bursa beneath the deltoid.