MUSCLES OF THE PELVIC LIMB 381 
of the lateral face of the tibia and the fibula. 
Its tendon accompanies that of 
the lateral extensor over the lateral malleolus, 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 from the rough lines above the condyles of the 
femur. The origin of each head contains a sesamoid 
bone about the size of a pea (Os sesamoideum m. gas- 
trocnemii), which articulates 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 common with the lateral head of 
the gastrocnemius from the lateral rough line and sesa- 
moid bone, and from the aponeurosis of the vastus 
lateralis. The tendon winds around that of the gas- 
trocnemius, passes over the tuber calcis (where it 1s 
arranged as in the horse), and divides below the tarsus 
into two branches. Each of these divides into two 
branches which end as in the forelimb. The lateral 
and medial 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 has two heads. The large 
lateral head, the flexor hallucis longus, arises from the 
posterior surface of the tibia and fibula, filling the in- 
terosseous space. The small medial head, flexor digi- 
talis pedis longus, also arises from the tibia and fibula; 
its tendon passes through the groove on the medial 
malleolus, inclines backward in its descent over the 
tarsus, and joins that of the large head below the 
tarsus. The common tendon detaches a branch to 
the large digital pad and terminates as in the forelimb. 
The tibialis posterior is a very small but distinct 
_ muscle, which arises on the proximal part of the fibula. 
The delicate tendon accompanies that of the flexor 
longus and ends on the medial ligament of the tarsus. 
The tendon of origin 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 plantz arises on the lateral 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 tendin- 
ous slip which extends from the plantar surface of the 
proximal part of the fibular tarsal bone to the head of 
the fifth metatarsal bone; the other part arises from 
on the first phalanx of the fifth digit. 
Fic. 
Foor or Doa; 
327.—MutscLes oF LEG AND 
LaTERAL VIEW. 
a, Quadriceps femoris; )b, 
trocnemius, lateral head; c, 
ficial digital flexor; d, deep digital 
gas- 
super- 
flexor; e, peroneus longus; /, ten- 
don of lateral extensor; g, peroneus 
brevis; hk, long digital extensor; h’, 
h’’, h’’’, tendons of preceding; i, 
tibialis anterior; k, extensor brevis; 
1, slips from interossei (m); 1, lateral 
patella; 3, 
5, 6, annular 
condyle of femur; 2, 
tibia; 4, tuber calcis; 
ligaments. (After Ellenberger, in 
Leisering’s Atlas.) 
the medial surface of the fibular tarsal bone (or from the tendinous part) and ends 
In case the skeleton of the first digit is well developed, there are three muscles 
