OSTEOLOGY. 51 



The head is connected to the body of the scapula by a con- 

 stricted portion, the neck, from the anterior surface of which 

 arises the coracoid process. It presents 



The glenoid cavity or fossa, a shallow, pyriform, articular 

 depression, deepened in the recent state by the glenoid ligament, 

 for the head of the humerus. To its upper part or apex is 

 attached the long head of the biceps muscle. 



THE ACROMION PROCESS, forming the summit of the 

 shoulder, is a triangular process, projecting forward, outward, 

 and upward to overarch the glenoid cavity. It gives attachment 

 by its upper surface to the platysma and deltoid and by its inner 

 margin to the trapezius. It presents 



An apex, for attachment of coraco-acromial ligament; 



Articular facet, just behind the apex for the clavicle. 



THE CORACOID PROCESS (like a crow's beak) arches forward, 

 upward, and inward above the glenoid cavity. It presents : 



Attachment for pectoralis minor muscle from the anterior 

 border near the tip ; 



Apex, for attachment of coraco-brachialis and short head of 

 biceps ; 



Rough impression at the inner side of the root for the 

 conoid ligament, and from it 



A ridge running outward and forward for the trapezoid 

 ligament. 



It articulates with the .clavicle and humerus. 



Its muscular attachments are 18: platysma, supra- and 

 infra- spinatus, subscapular, deltoid, trapezius, omo-hyoid, ser- 

 ratus magnus, levator anguli scapulae, rhomboideus major and 

 minor, triceps, teres major and minor, biceps, coraco-brachialis, 

 pectoralis minor, and latissimus dorsi. 



Its ossific centres are seven one each for body, posterior 

 border, and inferior angle, and two each for acromion and cora- 

 coid processes. 



THE HUMERUS, or ARM-BONE, the largest and longest bone 

 of the upper extremity, consists of a shaft, head, neck, greater 

 and lesser tuberosities, and lower extremity. 



The shaft, cylindrical above, flattened and prismoid below, 

 becomes twisted in the middle, and presents 



A rough triangular surface about the middle of its outer sur- 

 face for insertion of the deltoid muscle, and a 



Musculo-spiral groove /or the musculo-spiral nerve and supe- 

 rior profunda artery, on cadi side of which arise the external and 

 internal heads of tin- triceps muscle. 



The upper exlrcmily presents 



