THE SKELETON 



33 



Parietal 



Elhmniil 



Occipital 



Fig. 33. — Human Skull, 

 disjointed. 



felt. The high ridge which runs across the bone can be 

 felt extending to the top of the shoulder. 



The Pelvic Girdle. — The edges of the hip bones can be 

 felt at the sides of the hips (Fig. 28). The hip bones, 

 with the base of the spine, 

 form a kind of basin called 

 the pelvis. 



The skull (Fig. 33) rocks, 

 or nods, on the top vertebra. 

 It consists of the cranium, or 

 brain case, and the bones of 

 the face. The shapes and 

 names of the bones of the 

 skull are shown in Fig. 33. 



Adaptations of the Skull 

 for Protection. — Its arched 

 form is best for resisting pressure and turning aside blows. 

 Like all flat bones, the skull has a spongy layer of bone 

 between the layers of compact bone forming the outer and 

 inner surfaces ; hence it is elastic and not easily cracked. 

 The nose, brow, and cheek bones project around the eye 

 for its protection. The delicate portions of the ear are 

 embedded in the strongest portion of the skull. The 

 branches of the nerves of smell end in the lining of the 

 bony nasal chambers. The spinal cord rests securely in 

 the spinal canal. 



The arms and legs have bones that closely correspond to 

 each other. The Latin names of these bones, as well as 

 of all the other bones, are given in Fig. 28. There are 

 30 bones in each arm and 30 in each leg (Fig. 34). 

 Here is a list of the bones of the arm, followed by the 

 names in brackets of the corresponding leg bones : upper 

 arm bone [thigh bone], 2 forearm bones [shin bone and 



