MUSCLES OF THE LEG AND FOOT 



309 



V. MUSCLES OF THE LEG AND FOOT 



There are four digital extensors, two of which are fused with each other and 

 the peroneus tertius in the upper third of the leg. 



1. The anterior or long digital extensor {M. extensor digitahs longus) arises 

 by the common tendon in the extensor fossa of the femur, and separates from the 

 other muscles near the middle of the leg. At the distal end of the tibia it termi- 



FiG. 223. — Muscles of Leg and Foot of Ox, Inner View. 

 a, Peroneus tertius; b' , tendon of anterior or long extensor; e, deep digital flexor; e', tendon of e; e", branch 

 of h to superficial flexor tendon; /, gastrocnemius; g, tendon of superficial digital flexor; h, interosseus metlius 

 or suspensory ligament; (, annular ligaments; I, branch of h; m. long digital flexor; o, popliteus; 20, patella; 28, 

 tuberosity of tibia. (After Ellenberger-Baum, Anat. fiir Kunstler.) 



nates on a tendon which passes down over the hock (bound down, by two annular 

 Hgaments) and ends like that of the thoracic limb. 



2. The internal digital extensor (M. extensor digiti tertii proprius) arises in com- 

 mon with the preceding muscle and the peroneus tertius, and is covered by them 

 to the distal third of the tibia. Its tendon passes under the annular ligaments 

 between those of its cogeners and ends on the second phalanx of the inner digit. 



3. The lateral digital extensor (M. extensor digitalis lateralis s. digiti quarti 

 proprius) arises on the external lateral ligament of the stifle joint and the external 

 condyle of the tibia. Its tendon passes over the outer surface of the hock, and 

 terminates on the anterior surface of the second phalanx of the external digit. 



