iv.] SKELETON OF UPPER LIMB. 165 



dyle, as e.g. in the Wombat. This serves to transmit the 

 median nerve and brachial artery, which are thus protected 

 by bone in a way found only by a very rare exception indeed, 

 if ever, in man. There may be a notch or a foramen above 

 the external condyle, as in some Lizards, e.g. Psammosa&rus. 

 The transverse extent of the inferior articular surfaces of 

 the humerus of man is greater than in very many forms, on 

 account of the articular surface for the radius coming to be 

 in front of, instead of at the side of, that for the ulna. We 

 see this very distinctly, e.g -., in the Dog. 



FIG. 141. ANTERIOR SURFACE OF RIGHT HUMER 

 vojubatns). 



h, head ; kg, bicipital groove : t, great or radial tuberosity ; f, small or ulnar 

 tuberosity ; dr, deltoid ridge ; sr, supinator ridge ; cf, supra-condylar foramen ; 

 ec, external condyle ; ic, internal condyle ; ar, articular surface for ratlius ; 

 au, articular surface for ulna. 



(From Flower's " Osteology") 



The fossae for the coronoid process and olecranon, which 

 sometimes communicate by a perforation in man's humerus, 

 may do so normally and constantly, as e.g. in the Hare. 



Rarely (as in some Tailed- Batrachians) a dense ligament 

 may connect the head of the humerus with the glenoid cavity, 

 as we shall see that the head of the thighbone is normally 

 connected with the cavity which receives it. 



