Fracture of Scapula 227 



The sternal end of the clavicle has an epiphysis which begins to 

 ossify about the eighteenth year and joins the shaft a few years later. 

 Occasionally this epiphysis becomes 



detached, when careful measurement //""jS^" ^"~- - "^^* 



shows that the lesion is not a dislo- (*r' "^^"^^tin ' fiT 'SntJ^ffi 



Epiphysis, 2, of clavicle at sternal end. 



In excision of the bone the peri- 

 osteum should be stripped off by the blunt raspatory, the knife being- 

 used only for the skin ; thus there is but little risk of wounding the sub- 

 clavian and supra-scapular vessels and the external jugular vein. 



The scapula reaches from the second to the seventh rib. Its 

 spine at the base corresponds to the third rib, and marks the posterior 

 limit of the fissure between the upper and lower lobes of the lung 

 (p. 192). The subscapularis and serratus magnus intervene between 

 the scapula and the ribs. The bone is held in position by certain clavi- 

 cular ligaments, and by the trapezius, levator anguli, rhomboids, and 

 serratus magnus. The latissimus dorsi may be left out of the calculation, 

 as its connection with the inferior angle is but slight and inconstant. 



Luxation of scapula is that condition in which the inferior angle 

 projects from the chest- wall. It is due, not to the angle having 

 slipped over the border of the latissimus, but to paralysis of that part 

 of the serratus which should hold the vertebral margin and the inferior 

 angle against the chest. Frictions, and electrical stimulations along 

 the nerve of Bell, usually efface the deformity. 



The acromion and the coracoid processes have each two centres 

 of ossification ; they may become ' unglued,' especially so the latter, 

 by direct violence or muscular action. The coracoid is ossified on 

 to the rest of the scapula at puberty, the acromion at manhood. 



After fracture of the coracoid the pectoralis minor, coraco-brachialis, 

 and short head of biceps drag at the loosened process, but are 

 unable to displace it materially, as the conoid and trapezoid ligaments 

 still fix it to the clavicle. The fracture is treated by flexing the elbow 

 (to slacken the biceps), and by drawing it across the chest (to take the 

 strain from the pectoralis minor and coraco-brachialis), and by fixing 

 the arm in that position for two or three weeks. The break may be 

 repaired by a ligamentous union. Probably not a few of the specimens 

 which are described as * ununited fracture of the coracoid ' are instances 

 of imperfect ossification, fracture, especially from violence, being of 

 rare occurrence. The only other fracture of the scapula which is of 

 anatomical importance is that of the neck, when the coracoid process 

 and the glenoid cavity are detached, and descend together with the 

 head of the humerus into the axilla. The injury is excessively rare ; 

 it is distinguished from simple downward dislocation of the humerus 

 by the fact that the contour of the shoulder is easily restored when 

 the arm is raised, though it recurs directly the support is removed. 

 In dislocation of the humerus the bone is firmly locked. 



o 2 



