1 4 Physiology. 



(d) Gliding, as between the short bones of the wrist 

 and of the ankle. 



Study of Joints. Examine these joints in the prepared skeleton, 

 and so far as possible, in sheep shanks, or in fresh specimens of, rabbits. 

 Compare the ball and socket joints of the hip and shoulder. Also com- 

 pare the hinge joints of the knee and elbow. 



Hygiene of the Bones. Sometimes the bones of chil- 

 dren are lacking in mineral matter, and are too soft and 

 flexible. This is true in a disease called rickets. Even if 

 the bones are natural, children should not be encouraged 

 to walk early, as bow-legs may result. Most bow-legged 

 persons seem to be active, and probably their muscles 

 developed faster than the bones. Unnatural positions or 

 over-use of special groups of muscles may result in lateral 

 curvature of the spine. The height of seats and desks 

 should be carefully looked after. 



Sprains and Dislocations. Sprains and dislocations are 

 injuries to the joints, and often bring more serious results 

 than a broken bone. There should, usually, be complete 

 rest until the part can be used without pain. Otherwise a 

 stiffened joint may result. Hot water applied to a sprain 

 or bruise aids circulation and prevents discoloration. But 

 if there is inflammation, cold water should be applied. 

 Bandages may be needed for support. 



Broken Bones. When a bone is broken, of course a 

 physician should be sent for. Care must be taken that the 

 limb be kept straight. If this is not done, the sharp ends 

 of the bone (see Fig. 22) may cut or tear the surrounding 

 tissues, or even cut blood tubes. So, if the person must 

 be carried, it is well to tie a piece of board along the limb 

 to keep from bending it. A cane, umbrella, or any light 

 rigid bar will serve for this purpose. 



