CHAPTER IV 



THE BONES— FRACTURES AND EXOSTOSES 



THE SCAPULA 



This flattened and somewhat triangular bone is situate on the antero- 

 lateral aspect of the thorax. It presents two surfaces, three edges, and 

 three angles. The bone is not fixed in position, but is movable on the 

 wall of the thorax, to which its deep tace or ventral surface is applied. 

 Its long axis takes a direction which is downwards and forwards. The 

 body of the bone is not exposed to great risks of injury, since the outer 

 surface or dorsum is well clothed by muscles. On this surface, how- 

 ever, there extends longitudinally a prominent ridge called the spine, 

 which may be felt in the living animal, and which is most exposed just 

 above its middle, where it forms what is known as the tubercle of the 

 spine, to which the trapezius muscle is attached. This is the only 

 portion of the spine which is very exposed, since the ridge is peculiar 

 in the horse in not being produced inferiorly into an acromion process, 

 but at either extremity it gradually subsides to the level of the surface of 

 the body of the bone. 



The most important angle of the scapula is the inferior, since this 

 presents the coracoid process and the glenoid cavity. The former is 

 placed superiorly at this angle. It is a roughened eminence which is 

 elongated from above to below, and from the inner aspect of which there 

 projects a well-defined tubercle. From the coracoid process the tendon 

 of origin of the biceps flexor brachii muscle arises, whilst the tendon of 



