88 



Bones of the Upper Extremity. 



Angulus medialis 



Margo superior 



Fossa supraspinata Acromion 



Spina scapulae Processus coracoideus / 



Margo / 

 vertebralis 



Angulus lateralis 



^Tuberositas infraglenoidalis 

 Collum scapulae 

 Fossa infraspinata 



Margo axillaris 



Angulus inferior- 



109. Right shoulder blade, scapula, from behind. 



The posterior surface of the shoulder blade, facies dorsalis scapulae, is convex and 

 subdivided by a bony projection, spina scapulae, which ascends about at the junction of the 

 upper with the middle third, into the upper smaller, deeper fossa supraspinata and the lower, 

 larger, flatter fossa infraspinata. The spina scapulae is low where it begins at the margo 

 vertebralis and develops gradually to a very powerful high plate of bone which possesses an 

 upper surface, directed also somewhat forward, and a lower surface, looking also somewhat 

 backward. The free margin is broad. A strong process (the acromion} goes off from the side 

 of it, first lateralward, then forward; it looks flattened out in its most anterior part and 

 presents an upper and a lower surface; near its apex it presents medianward a small oval 

 facies articularis acromii for articulation with the facies articularis acromialis claviculae; the 

 acromion is rarely, in the adult, separated by cartilage from the spina scapulae. 



