PECTORAL GIRDLE. 421 



II. THE APPENDICULAR SKELETON. 



A. The Pectoral Girdle. 



The pectoral girdle is stout, and is firmly connected with 

 the sternum to give support to the wings. It differs markedly 

 from that of the rabbit in the large size of the coracoid, 

 which is almost perpendicular to the scapula ; and in the 

 completeness of the clavicle. 



i. The scapula is a long flattened blade-like bone 

 which in the natural condition of the parts 

 lies above the ribs, a short distance from and 

 almost parallel to the vertebral column. It 

 is connected by muscles with both the ribs 

 and the vertebrae. Its anterior end, which 

 is expanded and firmly connected with the 

 coracoid, bears on its outer surface a shallow 

 depression forming part of the glenoid cavity ; 

 and is produced forwards, at its inner border, 

 into a process which helps to form the canal 

 for the tendon of the second pectoral muscle, 

 ii. The coracoid is a stout straight bone running 

 from the shoulder to the anterior end of the 

 sternum. Its upper end is connected behind 

 and at its inner side with the scapula, and 

 bears on its outer surface a cup-shaped de- 

 pression, which forms the greater part of the 

 glenoid cavity. 



Above the glenoid cavity, the coracoid is 

 produced upwards and inwards into a strong 

 process, which, with the corresponding pro- 

 cess of the scapula, completes the foramen 

 triosseum, through which the tendon of the 

 second pectoral muscle passes to its inser- 

 tion into the back of the humerus. This 

 process also articulates with the clavicle. 



The lower end of the coracoid is broad and 

 flattened, and bears a transversely elongated 



