_Clinical Features._--The attitude of the patient is characteristic: the elbow is flexed and is supported by the opposite hand, while the head is inclined towards the affected shoulder to relax the muscles of the neck. Crepitus is elicited on bracing back the shoulders, or on attempting to raise the arm beyond the horizontal, and these movements cause pain. Tenderness is elicited on making pressure over the seat of fracture, and also on distal pressure. The sternal fragment almost invariably overrides the acromial, and can usually be palpated through the skin; on measurement, the clavicle is found to be shortened. When the fracture is incomplete (greenstick) or transverse, the symptoms are less marked. [Illustration: FIG. 14.--Fracture of Acromial End of Clavicle. Shows forward rotation of lateral fragment, and line of fracture united by bone.] Fracture of the _lateral_ or _acromial third_ of the clavicle is a common form of accident at football matches, and usually results from direct violence, the bone being driven down against the coracoid process, and broken as one breaks a stick over the knee. The fracture may take place through the attachment of the conoid and trapezoid ligaments, in which case the only symptoms are pain and tenderness at the seat of fracture, with impaired movement of the limb. Displacement and crepitus are prevented by the splinting action of the ligaments. When the break is lateral to the attachment of the trapezoid ligament, the fracture is usually transverse, and is almost always due to a fall on the back of the shoulder--the angle between the spine and the acromion process striking the ground. The acromial fragment rotates forward (Fig. 14), sometimes even to a right angle, causing the tip of the shoulder to pass forwards, and so to lie slightly nearer the middle line. The integrity of the coraco-clavicular ligaments prevents any marked drooping of the shoulder. It is noteworthy that the displacement is not always evident at first. Fractures of the _medial_ or _sternal third_ are rare, are usually oblique, and result either from an indirect force acting in the line of the clavicle, or, less frequently, from direct violence or muscular action. As a rule, the deformity is insignificant, except when the costo-clavicular ligament is torn, in which case the medial end of the distal fragment is tilted up by the weight of the arm. The shoulder passes downwards, forwards, and medially. When close to the sternal end, this fracture may simulate a dislocation of the sterno-clavicular joint or a _separation of the clavicular epiphysis_. This last is a rare accident, which may occur between the seventeenth and the twenty-fifth years, and is usually the result of violent muscular action. It differs from the other injuries in this region in being more easily reduced and retained in position, the epiphysis lying entirely within the limits of the articular capsule of the sterno-clavicular joint.