THE SCAPULA. 



177 



these motions of the clavicle ; and the general use of the bone 

 is to regulate the motions of these parts. 



From the situation, figure, and use of the clavicles, it is evident 

 that they are much exposed to fractures ; that their broken 

 parts must generally pass each other, and that they will be kept 

 in their places with difficulty. 



Fig. 40.* 



The Scapula, 



Or shoulder-blade, is the triangular bone situated on the upper 

 and back part of the thorax. The back part of the scapula has 



nothing but the thin ends of the 

 serratus anticus major, and sub- 

 scapularis muscles between it 

 and the ribs : but as this bone 

 advances forwards, its distance 

 from the ribs increases. The 

 longest side of this bone is near- 

 est the spine, and has an oblique 

 position as respects it. The up- 

 per or shortest side, called the 

 superior costa of the scapula, is 

 nearly horizontal, and parallel 

 with the second rib. The lower 

 side, which is named the inferior 

 costa, is extended obliquely from 

 the third to the eighth rib. The 

 situation of this bone, here described, is, as when people are sit- 

 ting or standing, in a state of inactivity, and allowing the mem- 

 bers to remain in the most natural easy posture. The inferior 

 angle of the scapula is very acute ; the upper one is near to a 



* A posterior view of the scapula. 1. The supra-spinous fossa. 2. The infra- 

 spinous fossa. 3. The superior border. 4. The supra- scapular notch. 5. The 

 anterior or inferior border. 6. The head of the scapula and glenoid cavity. 7. 

 The inferior angle. 8. The neck of the scapula, the ridge opposite the number 

 gives origin to the long head of the triceps. 9. The posterior border or base of 

 the scapula. 10. The spine. 11. The triangular smooth surface, over which 

 the tendon of the trapezius glides. 12. The acromion process. 13. One of the 

 nutritious foramina. 14. The coracoid process. 



