THE LEG 377 



anterior part of the popliteal groove on the lateral surface 

 of the lateral condyle of the femur. The tendon pierces 

 the posterior part of the capsule of the knee joint, and the 

 fleshy fibres which arise from it are directed medially and 

 distally, and spread out to obtain insertion into the posterior 

 surface of the tibia proximal to the linea pop'litea, and also 

 into the fascia which covers the muscle. 



The nerve to the popliteus has already been seen to arise 

 from the tibial nerve. It can now be seen hooking round the 

 distal margin of the muscle to reach its anterior surface. 

 The popliteus is a flexor of the knee and a medial rotator 

 of the leg. 



M. Flexor Hallucis Longus. The long flexor of the great 

 toe is a powerful muscle which arises from the posterior 

 surface of the fibula, distal to the origin of the soleus, from 

 the posterior fibular septum, and from the surface of the 

 fascia covering the tibialis posterior. After passing behind 

 the ankle joint its tendon occupies a deep groove on the 

 posterior border of the talus, then it turns forwards under 

 cover of the ligamentum laciniatum to gain the sole of the foot. 

 The flexor hallucis longus is supplied by the tibial nerve. It 

 is a flexor of the interphalangeal and metatarso-phalangeal 

 joints of the great toe, a plantar flexor of the foot, and it 

 assists in producing inversion of the foot. 



M. Flexor Digitorum Longus. The flexor digitorum longus 

 arises from the posterior surface of the body of the tibia, distal to 

 the popliteus, and medial to the vertical ridge which descends 

 from the linea poplitea. It also derives fibres from the surface 

 of the fascia which covers the tibialis posterior. After 

 crossing superficial to the distal part of the tibialis posterior, 

 its tendon grooves the back of the medial malleolus on the 

 lateral side of the tendon of the tibialis posterior. It is con- 

 tinued under cover of the ligament laciniatum into the sole 

 of the foot. The flexor digitorum longus is supplied by the 

 tibial nerve. It is a flexor of the interphalangeal and meta- 

 tarso-phalangeal joints of the lateral four toes, and it assists 

 in producing plantar flexion and inversion of the foot. 



M. Tibialis Posterior (O.T. Tibialis Posticus). The 

 tibialis posterior takes origin from the posterior surface of 

 the interosseous membrane, from the posterior part of the 

 medial surface of the body of the fibula, from the posterior 

 surface of the body of the tibia, on the lateral side of the 



