I08 THE PRINCIPLES OF MYODYNAMICS. 



raised the weight of the body rests on the 

 posterior pillar. The plantar fascia is very 

 important in the construction and mechanism of 

 the foot ; so much so, when it is too long or too 

 short, the function of the foot is more or less dis- 

 turbed. — The- sub-astragoloid joint has already 

 been noticed. The medio-tarsal joint is where 

 the OS calcis and astragalus meet the cuboid and 

 scaphoid bones, and is a ginglymus, having con- 

 siderable flexion and extension. The medio- 

 pedal joint is where the os calcis, the cuboid 

 bone, and the fourth metatarsal bone meet the 

 astragalus, the scaphoid, and external cruciform 

 bones, and the third metatarsal bone, and runs 

 longitudinally through the foot. The joint be- 

 tween the head of the astragalus and the 

 scaphoid bone resembles a ball-and-socket joint, 

 and facilitates inversion of the foot, as the os 

 calcis glides inward under the astragalus, the 

 latter bone only moving backward and forward 

 as the foot is flexed and extended. — The foot is 

 admirable for its strength and adaptation, but its 

 usefulness is often diminished by neglect and 

 ignorance. 



