The Leg. 371 



completely extended the foot, they tend to slightly adduct 

 it and to invert the sole. The popliteus, from the outer 

 side of the external condyle and from the posterior liga- 

 ment of the knee joint; into the inner two-thirds of the 

 triangular surface above the oblique line of the tibia and 

 into the fascia covering the muscle. Action. It feebly 

 flexes the tibia and at the same time rotates it inward 

 slightly. Its attachment to the posterior ligament tends 

 to draw back this ligament in flexion of the leg and so pre- 

 vent it from being "nipped" between the bones in that 

 movement. Plantaris. From the lower two inches of the 

 outer bifurcation of the linea aspera and from the pos- 

 terior ligament of the knee joinit ; into the os caleis, or the 

 tendo Achilles, or into the plantar fascia. Action. To 

 feebly extend the ankle and to flex the knee like the gas- 

 trocnemius, and, like the popliteus, to prevent the pos- 

 terior synovial membrane from being caught between the 

 bones in flexion of the leg. Nerves. The above muscles, 

 having actions somewhat similar, are all supplied by the 

 same nerve, viz., by the internal popliteal. 



Beneath the deep tibial fascia, which is attached to the 

 inner border of the tibia, internally, and to the outer bor- 

 der of the flexor surface of the fibula, externally, and 

 which is thicker below, blending in this situation, with 

 the deep fascia of the leg, are the following muscles : 

 Flexor longus digitorum. From the posterior surface of 

 the tibia below the oblique line, to within three inches 

 of the ankle joint, and from the adjoining deep fascia ; in- 

 to the bases of the last phalanges of the four outer toes. 

 Action. It flexes the last phalanges and assists in the 

 flexion of the second and first phalanges, and of the front 

 part of the foot at the medio-tarsal joint, and, in addition, 

 it assists slightly in extension of the foot at the ankle joint. 

 Flexor longus hallucis. From the lower two-thirds of the 



