194 



DISSECTION OF THE LEG. 



Flexor 

 longus 

 tligitorum : 



origin ; 



enters 

 annular 



ligament ; 



part is 

 superficial 

 below 

 soleus ; 



use, with 

 foot free, 



and fixed. 



Tibialis 

 posticus : 



origin ; 



insertion ; 



muscles and 

 vessels in 

 relation 

 with it ; 



use, with 

 foot free, 



and fixed ; 

 in standing, 



in rising up. 



Aponeurosis 

 over the 

 muscle. 



The FLEXOR LONGUS DiGiTORUM (flexor perforaiis, fig. 74, E) 

 arises from the inner division of the posterior surface of the tibia 

 (fig. 73), extending from the attachment of the solens to about three 

 inches from the lower extremity, and from the aponeurosis cover- 

 ing the tibialis posticus. Its tendon enters a compartment in the 

 annular ligament, which is external to the sheath of the tibialis ; 

 and it divides in the sole of the foot into tendons for the last 

 phalanges of the four outer toes. 



The muscle is narrow and pointed above, where it is placed 

 beneath the soleus ; but in the lower half it is in contact with the 

 fascia, and the posterior tibial vessels and nerve lie on it. The 

 deep surface rests on the tibia and the tibialis posticus. 



Action. The muscle bends the farthest phalangeal joints of the 

 four smaller toes, and then extends the ankle. 



If the toes are in contact with the ground, the flexor helps to 

 raise the heel in walking ; and to move back the tibia in the act of 

 rising from stooping. 



The TIBIALIS POSTICUS (fig. 74, D) occupies the interval between 

 the bones of the leg, but it crosses over the tibia below to reach the 

 inner side of the foot. The muscle arises (fig. 73 and fig. 68, 

 p. 179) from the interosseous membrane, except about one inch 

 below, from an impression along the outer part of the posterior 

 surface of the tibia extending from the external tuberosity to the 

 middle of the bone, from the inner surface of the shaft of the fibula, 

 and slightly from the aponeurosis covering it. In the lower part 

 of the leg the muscle is directed beneath the flexor digitorum ; and 

 its tendon, entering the inner space in the annular ligament, reaches 

 the inner side of the foot to be inserted into the navicular and 

 other bones, as will be seen later (p. 212). 



The tibialis is concealed by the aponeurosis before mentioned, 

 and is overlapped by the neighbouring muscles ; but in the lower 

 part of the leg it is placed between the tibia and the long flexor of 

 the toes. On the muscle are the posterior tibial vessels and nerve. 

 The upper end presents two pointed processes of attachment that 

 to the tibia being the higher and between them the anterior tibial 

 vessels are directed forwards. 



Action. Its action 011 the movable foot is to depress the fore 

 part and outer side, and carry the toes inwards, producing the 

 movement in the tarsal joints known as inversion (p. 225), and to 

 extend the ankle-joint. The toes resting on the ground, it will aid 

 the muscles of the calf in raising the heel in the progression of the 

 body. 



In standing, the muscle can raise the inner border of the foot 

 with the tibialis anticus, so as to throw the weight of the body on 

 the outer edge. 



As the body rises from stooping, the tibialis draws back the bones 

 of the leg, with the soleus. 



The aponeurosis covering the tibialis is attached externally to the 

 inner border of the fibula ; but internally it joins the flexor longus 

 digitorum without being attached to bone : it may be regarded as 



