226 



The Clavicle 



readily reduced, it is often impossible to keep the clavicle in position 

 without obtaining, by a cutting operation, permanent ankylosis. 



The joint has a synovial membrane and a capsule which is thick- 

 ened by superior and inferior fibres. Sometimes the joint is divided by 

 an inter-articular fibre-cartilage. 



The conoid and trapezoid ligaments bind the outer third of the 

 clavicle to the coracoid process ; the conoid is behind and to the inner 

 side of the trapezoid, the base of the cone being upwards. 



The chief muscles attached to the clavicle are the pectoralis major 

 in the cylindrical and the deltoid in the flattened part, in front, and 

 the trapezius behind the deltoid. The sterno-mastoid arises along the 

 sternal third of the upper aspect, and the subclavius is inserted into the 

 groove on the under surface. 



Fracture of the clavicle usually occurs at about the middle of the 

 convex part, the cause being a fall on to the hand or shoulder. 



Signs oj 'the fracture. The shoulder at once drops, for there is now 

 nothing but the trapezius and the levator anguli scapulae to support the 

 weight of the arm. The dragging is so painful that the man usually 

 holds up the elbow in the other hand, and inclines his head to the 

 injured side. The collar-bone is intended not only to hold the shoulder 

 up, but to fend it from the chest. When, therefore, the bone is broken 

 the pectoralis major and minor, latissimus dorsi, subclavius, trapezius, 

 and rhomboids drag the scapula inwards, whilst the pectorals also drag 

 it somewhat forwards. 



The inner fragment does not stir : the costo-clavicular '(rhomboid) 

 and the adjacent ligaments hold it firm. As the finger is run along 

 the broken bone the sternal fragment certainly does 

 seem to be displaced, but it is not. It is the outer 

 part that has fallen in beneath it. 



The treatment consists in raising the elbow and 

 with it the drooping scapula and in bringing the 

 elbow across the chest, a large pad being placed in 

 the armpit. The pad acts as a fulcrum to the humerus 

 a lever of the first order : when the elbow is drawn 

 inwards the scapular end of the bone is thrust out- 

 wards. The hand is laid flat over the opposite 

 breast, and the arm, forearm, and hand are secured 

 by a wide roller, or strapping, for about three weeks. 

 When the clavicle is broken outside the conoid 

 ligament there is usually no displacement, for the 

 shoulder-blade is still suspended by that ligament ; 

 there maybe some dropping of the shoulder, however. 

 Complications. The broken bone may, if the 

 violence be great, wound the external jugular (p. 35), subclavian, or in- 

 ternal jugular vein, or even the subclavian artery. It may also lacerate 

 the brachial plexus. 



Fracture of cla 

 vicle. (DHL; ITT.) 



