MUSCLES OF THE PELVIC LIMB 



329 



the lateral extensor over the external malleolus of the tibia, and ends on the 

 proximal end of the fifth metatarsal bone. 



The soleus is absent. (It is present and large in the cat.) 



The gastrocnemius arises on the rough lines above the condyles of the femur. 

 The heads of origin each contain a bone about the 

 size of a pea — the sesamoid of Vesal — which articu- 

 lates with the corresponding condyle of the femur. 

 The tendon comports itself as in the horse. 



The superficial digital flexor has a large round 

 belly. It arises in conimon witii the outer head of 

 the gastrocnemius from the external rough line and 

 Vesalian sesamoid bone, and from the aponeurosis 

 of the vastus externus. The tendon winds around 

 that of the gastrocnemius, passes over the tuber 

 calcis (where it is arranged as in the horse), and 

 divides below the tarsus into two branches. Each 

 of these divides into two l^ranches which end as in 

 the fore limb. The outer and inner branches detach 

 slips to the suspensory ligaments of the large digital 

 pad. Muscle-fibers often occur in the tendon in the 

 metatarsal region. 



The deep digital flexor lias two heads. The 

 large outer head, the flexor hallucis longus, arises 

 from the tibia and fibula, filling the interosseous 

 space. The small inner head, flexor digitalis pedis 

 longus, also arises from the tibia and fibula, its tendon 

 joining that of the large head below the tarsus. The 

 common tendon detaches a branch to the large digital 

 pad and terminates as in the fore limb. 



The tibialis posterior is a small but distinct 

 muscle, which arises on the proximal part of the 

 fibula. The thin tendon accompanies that of the 

 flexor longus and ends on the internal lateral liga- 

 ment of the tarsus. 



The tendon of the popliteus contains a small 

 sesamoid bone. 



The adductors of the second and fifth digits, the 

 lumbricales, and the interossei are arranged as in the 

 thoracic limb. 



The quadratus plantae arises on the outer surface 

 of the distal end of the fibular tarsal bone and on the 

 lateral tarsal ligament, passes downward and inward, 

 and terminates on a thin tendon which fuses with 

 that of the deep flexor. 



The abductor digiti quinti is a very small muscle 

 which consists of two parts. One of these is a ten- 

 dinous slip which extends from the posterior surface 

 of the proximal part of the fibular tarsal bone to the 

 head of the fifth metatarsal bone; the other part 

 arises from the inner surface of the fibular tarsal 

 bone (or from the tendinous part) and ends on the first phalanx of the fifth digit. 



In case the skeleton of the first digit is well developed, there are found three 

 muscles homologous with those of the same digit in the fore limb. These are the 

 abductor hallucis, adductor hallucis, and flexor hallucis brevis. 



Fig. 237. — Muscles of Leg and 

 Foot of Dog, External 

 View. 



a. Quadriceps femoris; 6, gas- 

 trocnemius, external liead; c, super- 

 ficial digital flexor; d, deep digital 

 flexor; e, peroneus longus; /, ten- 

 don of lateral extensor; g, peroneus 

 brevis; h, long or anterior digital 

 extensor; h', h", h"' , tendons of pre- 

 ceding; i, tibialis anterior; A-, exten- 

 .sor brevis; Z, slips from interossei (m) ; 

 1. external condyle of femur: 2, pa- 

 tella; 3, tibia: 4. tuber calcis; 5, 6, an- 

 nular ligaments. (After Ellenberger, 

 in Leisering's Atlas.) 



