MUSCLES AND FASCIA OF LOWER EXTREMITY 169 



in the muscle, one from the fibula and one from the 

 tibia. Fibers from the anterior surfaces of these laminae 

 converge to a median septum; fibers from their pos- 

 terior surfaces pass down and back to an aponeurosis 

 covering the back surface of the muscle. The tendon 

 of insertion is prolonged from this aponeurosis, joined 

 by the median septum. Muscular fibers are continued 

 down on the deep surface of the tendo Achillis near 

 to the heel. 



The gastrocnemius and soleus form the calf of the leg. 



Tendo Achillis, broad at fir^t, contracts to within 

 1J inches of the heel, then expands, and is inserted 

 into the middle and lower parts of the posterior surface 

 of the tuberosity of the os calcis, a bursa having all 

 the characters of a synovial membrane, with vascular 

 and fatty synovial tufts, separating it from the upper 

 part of this surface. 



Plantaris. Origin, femur above the external condyle 

 and from the posterior ligament of the knee-joint. 

 Muscular belly 3 to 4 inches long, and the long, slender 

 tendon turns in between the gastrocnemius and soleus 

 to the inner border of the tendo Achillis, and inserted 

 by its side into the os calcis. 



Popliteus. Origin, round tendon, one inch long, from 

 the groove on the outer surface of the external condyle 

 of the femur, within the capsule of the joint, in contact 

 with the semilunar cartilage, and by muscular fibers 

 from the ligamentum popliteus arcuatum. Fibers 

 pass down and are inserted into the triangular surface 

 of the tibia above the oblique line, and into the 

 aponeurosis over the muscle. 



THE DEEP MUSCLES (Flexors) Flexor Longus Digi- 

 torum Pedis. Origin, inner portion of the posterior 

 surface of the tibia for the middle two-fourths of its 

 length, from the aponeurosis over the tibialis posticus. 

 Descends behind the internal malleolus of the tibia, 

 passes forward and obliquely outward, having crossed 

 the tibialis posticus tendon in the leg, and now crossing 



