144 THE PRINCIPLES OF MYODYNAMICS. 



showing that the thigh is generally equal in 

 length to the leg and vertical diameter of the 

 foot : The height of the plantar arch and the 

 length of the tibia make a lever of about the 

 same length as the femur. Hence, when the 

 foot-and-leg lever and the femoral lever are 

 antagonistic, and have equal lever-arms, they 

 are in a condition of dynamic equality, or per- 

 haps it might be more correct to say that they 

 are in equilibrium. 



THE SKULL AND THE CRANIO- VERTEBRAL JOINT. 



136. The condyles of the skull rest on the 

 atlas, and the atlas rests on the axis ; and the 

 odontoid process of the axis is where the body 

 of the atlas would be — if it had one. The skull 

 has the following motions — namely, 



(a.) (i.) Flexion ; (ii.) extension ; (iii.) right 

 rotation ; (iv.) left rotation ; (v.) right adduc- 

 tion ; (vi.) left adduction. 



(i.) The flexors of the skull are : The rectus 

 capitis anticus minor, the rectus capitis anticus 



