314 FASCL® AND MUSCLES OF THE HORSE 
the deep flexor emerges (Fig. 278). A second synovial membrane, the digital 
synovial sheath (Vagina digitalis), begins at the distal fourth of the metacarpus, 
Fig, 283.—SyNoviaL SHEATHS AND Burs® oF Distau Fie. 284.—SyNoviaL SHEATHS AND Burs.© oF DISTAL 
Part or Rieut Fore Limp or Horse; Mepiau Part or Rieut Fore Limp or Horse; LarerRAL 
VIEW. VIEW. 
The synovial sheaths (colored yellow) and the joint capsules (colored pink) are injected. 
a, Sheath of extensor carpi obliquus; 6, sheath a, Sheath of extensor carpi radialis; 6, sheath 
of flexor carpi radialis; c, carpal sheath; d, d’, d’’, d’”’, of common extensor; c, sheath of lateral extensor; d, 
digital sheath; e, bursa under common extensor ten- sheath of outer tendon of ulnaris lateralis; e, e’, carpal 
don; f, capsule of fetlock joint; 1, extensor carpi ra- sheath; Jf, f’, /’, digital sheath; g, bursa under com- 
dialis; 2, tendon of extensor carpi obliquus; 3, flexor mon extensor tendon; h, bursa under lateral extensor 
earpi radialis; 4, flexor carpi ulnaris; 4, superficial tendon; i, capsule of fetlock joint; 1, extensor carpi 
flexor tendon; 6, deep flexor tendon; 7, suspensory liga- radialis; 2, common digital extensor; 3, lateral digital 
ment; 8, small metacarpal bone; 9, large metacarpal extensor; 4, ulnaris lateralis; 4’, 4’’, tendons of 4; 4, 
bone; 10, volar annular ligament of fetlock; 11, superficial flexor tendon; 6, deep flexor tendon; 7, 
proximal digital annular ligament; 12, radius; 13, suspensory ligament; 8, lateral metacarpal bone; 4, 
radiocarpal joint; 4, fetlock joint; 15, cartilage of large metacarpal bone; 10, volar annular ligament 
third phalanx; 1/6, band from first phalanx to cartilage. of fetlock; 71, digital annular ligament; 12, fetlock 
(After Ellenberger, in Leiscring’s Atlas.) joint; 13, cartilage of third phalanx; 14, band from 
first phalanx to cartilage. (After Ellenberger, in 
Leisering'’s Atlas.) 
« 
two or three inches (ca. 5-8 em.) above the fetlock, and extends to the middle of 
the second phalanx. 
Relations.—The belly of the muscle is related superficially to the ulnar head 
of the deep flexor, the flexor carpi ulnaris, and, at its origin, to the ulnar vessels 
