THE principlp:s of myodvnamics. 



1 1 1 



the inner and front side of the spine of the tibia 

 upward, backward, and outward to the inner 

 and back part of the external femoral condyle — 

 aiid limits the in-rotatioii of the leg, and prevents 

 displacement of the tibia backzuard, 



(6.) The posterior crucial ligament runs from 

 the depression behind the spine of the tibia 

 upward, forward, and inward to the outer and 

 fore part of the internal femoral condyle — and 

 limits 02tt -rotation of the leg, and prevents dis- 

 placemerd of the tibia fori<.^ard, 



(7.) The leg" has flexion, extension, and rota- 

 tion : — The flexion and extension of the leg- 

 takes place through an arc somewhat less than 

 two riorht angles. The leof can be rotated 

 through an arc of about fifteen degrees. The 

 rotation of the leg takes place around the center 

 of the tibial socket for the internal condyle of 

 the femur — the external socket of the tibia glid- 

 ing backward and forward under the external 

 condyle of the femur. This motion can be 

 clearly shown when the leg meets the thigh at 

 a right angle. 



104. The muscles that span the knee-joint 



