OSTEOLOGY. 71 



affords attacliment to extensor suffragiuis, and slightly 

 to extensor pedis. The inner at the radio-ulnar arch to 

 humeralis externns. Its anterior surface is that attached 

 to the radius, while its external and internal surfaces meet 

 in forming a rounded border posteriorly. The free portion 

 or olecranon presents two surfaces, three borders. The 

 anterior border is articulatory, concave from above down- 

 wards, convex from within outwards. It extends most on 

 to the onter surface. Inferiorly it widens, terminating 

 externally and internally in the synovial surfaces of the 

 attached portion of the bone. Frecjuently only the superior 

 part of this border is smooth, roughness extending com- 

 pletely across it at the inferior part. This surface articu- 

 lates with the supra-condyloid portion of the articulatory 

 surface of the humerus, thus assisting to form the elbow- 

 joint. Superiorly it forms an acute angle with the antero- 

 ■superior margin which is sharp, and extends obliquely 

 upwards and backwards. This angle is termed the hook- 

 like or hamular process. The antero- superior margin 

 posteriorly widens in joining the tuberous superior margin, 

 which anteriorly presents a smooth surface where rests a 

 bursa, and the tendon of triceps extensor brachii playing 

 over this becomes attached to the roughened part. The 

 external surface is convex, and roughened along its central 

 line from above downwards for attachment of some of 

 the muscular fibres of caput medium, and more anteriorly 

 of anconeus. Inferiorly it is smooth on becoming con- 

 tinous with the external surface of the attached portion of 

 the bone. The inner surface is smooth and concave. At 

 its junction with the superior margin it affords attachment 

 to one head of flexor metacarpi medius and to scapulo- 

 nlnaris. It blends with the external surface in forming the 

 rounded j^osterior margin, which is continuous with the 

 corresponding part of the attached portion, and which, at 

 its junction with the superior margin, affords attachment 

 to ulnaris accessorius. 



The CAHPITS—^' wrist" of human subject, ''knee" of 

 horse— 



■consists of seven or eight small bones arranged in two rows 

 between the radius and metacarpus. The bones composing 



