556 MAMMALIAN ANATOMY 



is directed from above downward and inward. It is slightly convex 

 from above downward. On well-marked bones it shows above, within, 

 and below the superior prominence of the internal surface the con- 

 tinuation medially of the transverse depression for the internal lateral 

 ligament. Below this depression is a deep transverse pit for the origin 

 of part of the humeral head of the flexor profundus digitorum muscle. 

 Below this again, limited behind by the lower sharp edge of the surface 

 itself, is a second equally well marked transverse pit for the origin of 

 the humeral head of the flexor carpi ulnaris muscle. 



The outer condyle is much simpler and less prominent than the 

 inner. It presents anterior and posterior surfaces. 



The anterior surface (Fig. 430) is small and narrow, and is the 

 continuation downward of the external surface of the shaft ; its upper 

 part lies between the supracondyloid ridge and the supratrochlear fossa; 

 it ends in a point below where the supracondyloid ridge meets the outer 

 end of the articular eminence. It affords origin to the extensor carpi 

 radialis brevior and extensor cornmunis digitorum muscles. 



The posterior surface (Fig. 431) of the outer condyle is the con- 

 tinuation of the posterior surface of the shaft downward, round the 

 olecranon fossa and the articular eminence. It is narrower above than 

 below, where it terminates in a rough line against the side of the 

 articular eminence. It is convex from above downward and slightly 

 convex from side to side. Its lower part is marked, just without the 

 sharp edge of the articular eminence, by a more or less developed 

 longitudinal depression. The posterior surface affords attachment to 

 the following muscles: on its inner side, to the anconeus; on the border 

 which it makes with the anterior surface, to the extensor communis 

 digitorum ; on the inferior line of junction with the articular eminence, 

 in the following order from above downward, to the extensor minimi 

 digiti, the supinator brevis, and the extensor carpi ulnaris. In the 

 deep pit on the side of the articular eminence, in front of this line, 

 is inserted the external lateral ligament of the elbow-joint. 



The articular eminence on the lower extremity of the humerus is 

 a spool-shaped mass extending transversely between the condyles. As 

 it articulates with both bones of the forearm, it presents a surface for 

 the end of each bone. That for the radius is known as the capi- 

 tellum, or smaller head of the humerus ; it forms the outer half of the 

 anterior aspect of the general articular surface, and ends in a point 



