286 



MUSCLES OF THE LOWER LIMB. 



lateral ligament and capsule of the knee-joint ; it is in contact with the 

 external semilunar cartilage, and receives additional fibres from the posterior 

 ligament of the joint. The muscular fibres diverge as they pass downwards, 



Pig 217 Fig- 217. DEEP POSTERIOR MUSCLES OP THE 



LEG. i 



a, popliteal surface of the femur ; 6, bare surface 

 of the upper fourth of the fibula, from which the 

 soleus muscle has been removed ; c, malleolus in- 

 ternus; d, malleolus externus; e, tuberosity of the os 

 calcis, with the tendo Achillis inserted into it, and the 

 plantaris on its inner side; 1, inner head of the gastro- 

 cnemius cut short at its origin ; 2, outer head ; 3, 

 plantaris; 4, tendon of the semimembrauosus muscle 

 near its insertion, seen spreading in three portions, 

 viz., to the inside of the tibia, towards the popliteal 

 fascia, and towards the ligamentum posticum ; 5, 

 tendon of the biceps inserted into the head of the 

 fibula ; 6, popliteus muscle ; 7, upper part of the 

 origin of the soleus from the fibula, cut short ; 7', line 

 of its tibial origin ; between these figures is seen the 

 perforation in the upper part of the interosseous 

 membrane; 8, tibialis posticus; 8', its tendon, pass- 

 ing between the flexor digitorum coinmunis and the 

 tibia ; 9, flexor digitorum communis ; 9', its tendon, 

 with that of the tibialis posticus, passing behind the 

 malleolus internus ; 10, flexor longus pollicis ; 10', 

 placed beside its tendon, where it passes over the 

 tibia and astragalus ; 11, peroneus longus ; 11', its 

 tendon behind that of the peroneus brevis, passing 

 down behind the malleolus externus ; 12, peroneus 

 brevis. 



and are inserted into all that triangular sur- 

 face of the tibia which is above the posterior 

 oblique line. 



The tendon of the popliteus muscle 

 occupies the groove on the femur in flexion 

 only. 



The popliteus is bound down by an aponeurosis, 

 principally derived from the tendon of the semi- 

 membranosus muscle. The popliteal vessels and 

 internal popliteal nerve lie upon its posterior 

 surface, and it is covered by the gastrocnemius 

 muscle. 



L 



The three remaining muscles of this group 

 are bound down together by a deep fascia, 

 which extends between the tibia and fibula, 

 and separates them from the soleus. 



The flexor longus digitorum pedis, or flexor 

 perforans, arises from the posterior surface 

 of the tibia, in the space below the oblique 

 line, and as far down as within three inches of 

 the inner ankle ; it likewise arises by aponeu- 

 rotic fibres connected with the flexor longus 

 pollicis, which pass over the surface of the 

 tibialis posticus. The fleshy fibres pass obliquely backwards into a tendon 



