THE BONES. 81 



Shape: triangular, shield-like, flat. 

 Portions : 2 surfaces, 3 borders and angles. 

 Connection : with the Clavicle and Humerus. 



a. Anterior surface, turned towards the ribs, concave ; this is Fossa sub- 

 scapularis, for m. subscapular., lying close to the surface of the back ; Scapulae 

 alatae stand off from it 



b. Posterior surface, divided into the smaller superior fossa supraspinata, 

 for m. supraspinatus, and a larger inferior fossa infraspinata, for m. infra- 

 spinatus, by the ridge, Spina scapulae, for trapezius, deltoid: this is triangular, 

 presents a superior and inferior surface, an external short, and a posterior 

 thick border, close beneath the skin, with a triangular surface, for the m. 

 Trapezius f passes forwards, upwards and outwards, to the top of the shoulder, 

 Acromion, which, triangular and flat, projects over the shoulder, protects the 

 articulation above and behind, and possesses at the superior border a small 

 articular surface for the Clavicle. 



c. Borders : 1. Internal, Vertebral border, Basis scapulas, the longest, with 

 an external lip, for m. rhomboideae, and an internal, for in. serratus antic, 

 major. 



2. External border, the thickest, inclined downwards and forwards towards 

 the arm [the axillary border], for m. teretes et anconaeus longus [long head of 

 the Triceps], above. 



3. Superior border, sharp, small, for m. omohyoideus with Incisurae scapulae s. 

 lunata, formed into a foramen by ligam. transversum, for nerv. suprascapular; 

 it passes into the coracoid process. 



d. Angles : 1. Internal, almost a right angle, for m. lev. anguli scapulae. 



2. Inferior, very pointed, m. Serratus magnus, attached to it, separated from 

 the skin by m. latissimus dorsi. 



3. External, is the oval, vertical Condylus scap. with the surface Cavilas 

 glenoidalis, the articular fossa for the head of the humerus, supported by a 

 Collum scapulas under which the Incisum colli, the junction of the fossae supra 

 et infra spinata, over which the Process, coracoideus projects, for the short 

 head of the biceps, at the apex m. coraco-brachialis, pectoral, minor, farther 

 above, ligam. coraco-clavicularia, acromiale. Proc. coracoid. bends under the 

 clavicle, forwards and outwards over the shoulder joint, and protects it from 

 before. 



Development : ossification commences in the centre, at the end 

 of the second month of the fcetus. In advanced childhood the 

 coracoid and acromion are still cartilaginous ; they contain, like 

 the posterior border and inferior angle, but not the spina^ special 

 osseous nuclei. The acromion has two, but later. The P. 

 coracoid unites with the body of the bone in the fifteenth to the 

 sixteenth year, the remaining points, especially the inferior border, 

 only after full growth. 



95. 2. Clavicula, furcula, Collar-bones, 2. 



Position : before and above the first rib, between shoulder- 

 blade and breast-bone, horizontal. 



Direction : both converge forwards and rather downwards, to 

 the Sternum. 

 6 



