212 OUTLINES or EQUINE ANATOMY. 



Extensor metacarpi obliqiuis arises from the outer part 

 of tlie middle third of the radius "between extensor' 

 suffraginis and extensor j)edis. Its muscular fibres in 

 running under the tendon of extensor pedis converge, and 

 they form a tendon which runs over extensor metacarpi 

 magnus (from wdiich it is separated by a bursa), passes 

 through the oblique groove on the inner surface of the in- 

 ferior extremity of the radius, through a channel in the 

 annular ligament of the knee, lubricated by synovia, ta 

 become inserted into the head of the inner small meta- 

 carpal bone through the medium of the inner lateral 

 ligament of the knee. 



Extensor pedis has a penniform arrangement. Supe- 

 riorly it blends with extensor metacarjn magnus in becoming' 

 attached to the external condyle of the humerus, and its- 

 fibres are attached to the inner lateral and capsular liga- 

 ments of the elbow-joint, and to the outer part of the 

 radius as far down as the inferior part of the superior 

 third. A remarkable round band of its muscular fibres 

 runs underneath extensor suffraginis to the foramen 

 between the ulna and the radius, where it becomes 

 attached in contact with the branches of the radial vessels 

 which pass through the foramen. While passing over ex- 

 tensor metacarpi obliquus the muscle becomes tendinous 

 and passes through the antero-external groove at the 

 antero- inferior part of the radius and the annular ligament 

 in a special channel, lubricated with synovia. Beloio the 

 Tcnee it sends a hranch to assist in foroning Ugamenium ex-- 

 tensorum. Between the upper part of this muscle and 

 extensor metacarpi magnus is a slight inflection of the 

 faschia of the arm, but a much thicker fold separates it from 



Extensor suiFraginis, and forms a sheath in which 

 this muscle plays, and whereby from the elbow to the knee 

 it is firmly fixed to the lateral part of the radius. It- 

 arises superiorly through the medium of the external' 

 lateral ligament from the outer condyle of the humerus, 

 at first forms a bridge over the erratic portion of extensor 

 pedis and then becomes fixed to the radius as above 

 mentioned. It passes through the external groove on 

 the antero-inferior part of the radius, and through the 

 annular ligament, from which it receives a fibrous cord 

 opposite the head of the small metacarpal bone, and 

 below the knee becomes rather expanded on the external' 



