114 77/ A' SKELETON 



major axis vertical; the lower end is the In-oader; the upper end or apex gives 

 oritiin to the long tendon of the hkeps. The margins are raised, and afford attach- 

 ment to the glenoid ligament. In the recent state, the cavity is covered with 

 h valine cartilage, and forms an articular fossa for the head of the humerus. The 

 niargin is somewhat defective where it is overarched liy the acromion. The cir- 

 cumference is rough for the attachment of the capsulai- ligament. Beyond this is 

 a narrow constricted i»ortion, called the neck of the scapula. 



Projecting upwards from the neck is tlie coracoid process, a ])rominehce of 

 bone anterior to, hut jiarallel with, the acromion. It consists of two parts — vertical 

 and horizontal. The vertical i)ait is compressed from within outwards; it is con- 

 tinuous ahove with the horizontal i)art and below with the neck of the scapula; its 

 outer bordi'r lies al)ove the glenoid cavity and gives attachment to the coraeo- 

 humeral ligament, and its inner border Avhich forms the outer boundary of the sui)ra- 

 sca{)ular niitch gives attachment to the suprascapular ligament; its anterior and 

 posterior surfaces are in relation with the .siib.scapularis and siipraspmatus respec- 

 tively. The horizontal })art runs forwards and outwards; it is compressed from 

 above downwards; its inner extremity gives attachment to the conoid ligament, 

 and its outer extremity, or apex, is for the attachment of the short head of the 

 biceps and the coraco-hrachialis ; the p^ectoralis minor is attached to part of the 

 anterior border and the upper surface, and the postero-internal part of the upper 

 surface is occupied by the trapezoid ligament. The posterior border gives attach- 

 ment to the coraco-acromial ligament. 



Muscles. — The following are attached to the scapula: — 



Su]>ra-siiinatus. Latissimus dorsi. 



Infra-spinatus. Trapezius. 



Subscapularis. Rhomboideus major. 



Teres major. Rhomboideus minor. 



Teres minor. Levator anguli scapulae. 



Omo-hyoid. Biceps. 



Pectoralis minor. Coraco-brachialis. 



Serratus magnus. Triceps (long head). 



Deltoid. 

 Ligaments : — 



Conoid. Capsular (shoulder-joint). 



Trapezoid. Coraco-humeral. 



Costo-coracoid membrane. Gleno-humeral. 



Costo-coracoid ligament. Glenoid. 



Capsular (acromio-clavicular). Rhomboid loop. 



Coraco-acromial. Spino-glenoid or inferior 

 Suprascapular (transverse). transverse. 



Blood-supply.— The scapula is supphed by the following arteries: — Twigs 

 from the sub.scai)ular artery and from the subscapular branch of the suprascapular 

 enter tlie bone; on the anterior surface. The dorsal artery of the scapula distributes 

 l)ranc]ies in the infraspinous, whilst the suprascapular artery supphes the supra- 

 spinous fossa, the spine, the glenoid fossa, and sends branches "into the infraspinous 

 fossa. The acromion is supi)lied l)y branches of the acromio-thoracic artery. 



Ossification. — The 8cai)ula is ossified from seven centres. Two may be con- 

 sidered as primary, and the remainder as secondary nuclei. The centre for the 

 body ai)pears in a phito of cartilage near the neck of the scapula about the eighth 

 week of mtra-uterine life, and (pijckly forms a triantrular plate of bone, from which 

 the spine appeai-s as a slight ridg(> about the middle' of the third month. At birth 

 the glenoid fossa and part of the scaindar neck, the acromion, coracoid, and verte- 

 bral border are cartilaginous. During tlie first vear a nucleus appears for the 

 coracoid, and at the tentii year a second centre ap)iears for the base of the coracoid 

 and the U|»per ])art of the glenoid cavitv. 



During the (ifleenth year the coracoid is ankvlosed to the scai)ula, and the 

 secondary centres appear. Two nuclei are deposited in the acromial cartilage, and 



