98 THE PRINXIPLES OF MYODYXAMICS. 



(3.) The two malleoli protect the sides of the 

 ankle-joint. (4 ) The extensor tendons are held 

 down by the annular ligament which, to some 

 extent, plays the part of a pulley. (5.) The 

 tendo-Achillis is also, to a limited extent, held 

 down by the annular ligament. (6.) The astra- 

 galus glides and turns backward and forward 

 under the tibio-fibular arch. (7.) The muscles 

 of the tendo-Achillis are especially used for 

 locomotion ; they are lifting muscles. (8.) The 

 tibiahs posticus, the flexor communis digitorum, 

 the flexor longus pollicis, the peroneus longus, 

 and the peroneus brevis are especially used to 

 flex, abduct, evert, and invert the foot. 



93. (a.) The extensors of the foot are the 

 tibialis anticus, the extensor longus pollicis, the 

 extensor longus digitorum, and the peroneus 

 tertius. When the extensors lift the anterior 

 part of the foot, the foot is a lever of the third 

 order. 



(b.) The flexors of the foot are the tibialis 

 posticus, the flexor longus digitorum, the flexor 

 longus pollicis, the muscles of the tendo-Achillis, 

 the peroneus longus, and the peroneus brevis. 



