JIUMERUS. 75 



surface, for the end of the clavicle. The nutritious foramina of 

 the scapula are situated in the base of the spine. 



The coracoid process is a thick, round, and curved process of 

 bone, arising from the upper part of the neck of the scapula, and 

 overarching the glenoid cavity. It is about two inches in length 

 and very strong; it gives attachment to several ligaments and 

 muscles. 



Developement. By six centres; one for the body, one for the 

 coracoid process, two for the acromion, one for the posterior border, 

 and one for the inferior angle. 



Articulations. With the clavicle and humerus. 



Attachment of Muscles. To sixteen ; by its anterior surface to 

 the subscapularis ; posterior surface, supra-spinatus and infra-spi- 

 natus ; superior border, omo-hyoid ; posterior border, levator an- 

 guli scapulae, rhomboideus minor, rhomboideus major, and serratus 

 magnus ; anterior border, long head of the triceps, teres minor, and 

 teres major ; upper angle of the glenoid cavity, to the long tendon 

 of the biceps ; spine and acromion, to the trapezius and deltoid ; 

 coracoid process, to the pectoralis minor, short head of the biceps, 

 and coraco-brachialis. The ligaments attached to the coracoid 

 process are, the coracoid, coraco-clavicular, and coraco-humeral, 

 and the costo-coracoid membrane. 



HUMERUS. The humerus is a long bone divisible into a shaft and 

 two extremities. 



The superior extremity presents a rounded head ; a constriction 

 immediately around the base of the head, the neck ; a greater and 

 a lesser tuberosity. The greater tuberosity is situated most exter- 

 nally, and is separated from the lesser by a vertical furrow the 

 bicipital groove, which lodges the long tendon of the biceps. The 

 edges of this groove below the head of the bone are raised and 

 rough, and are called the anterior and posterior bicipital ridge; the 

 former serves for the insertion of the pectoralis major muscle, and 

 the latter for the teres major. 



The constriction of the bone below the tuberosities is the sur- 

 gical neck, and is so named, in contradistinction to the true neck, 

 from being the seat of the accident called by surgical writers frac- 

 ture of the neck of the humerus. 



The shaft of the bone is prismoid at its upper part, and flattened 

 from before backwards below. Upon its outer side, at about its 

 middle, is a rough triangular eminence, which gives insertion to 

 the deltoid ; and immediately on each side of this eminence is" a 

 smooth depression, corresponding with the two heads of the bra- 

 chialis antic us. Upon the inner side of the middle of the shaft is a 

 ridge, for the attachment of the coraco-brachialis muscle ; and 

 behind, an oblique and shallow groove, which lodges the musculo- 

 spiral nerve and superior profunda artery. The foramen for the 

 medullary vessels is situated upon the inner surface of the shaft of 

 the bone, a little below the coraco-brachial ridge ; it is directed 

 downwards. 



