ELEMENTS OF PHYSIOLOGY 



FIG. 50. The Slug. 



instep, palm, fingers, and toes, which are the smallest of 

 the long bones, have the shaft and 

 heads. 



The many small short bones are 

 stronger than the long slender 

 bones, or the flat thin ones. These 

 bones are called irregular bones. 

 They are not easily broken and 

 their chief function is support. 



They are found in the spine, the ankle, the wrist, the knee, 



and the face. We should remember that the irregular 



bones also as- 

 sist in the two 



other functions 



of protection 



and motion; 



also that the 



long bones and 



the flat bones 



are not con- 

 fined to one 



function but 



participate in 



all three func- 

 tions (Fig. 49). 

 96. Another 



Use of Bories. 



Recent discov- 



erie s have 



shown that the 



red marrow in 



the small cavi- 



FlG. 51. Side View of Skull. 



larger bones are named in the figure. The lower jaw is dropped 

 down. Its socket in the skull is shown in front of the opening of 

 the ear, au ; z, process of temporal passing to malar, or cheek bone ; 

 c, one of the condyles or projections which rest in sockets on the high- 

 est vertebra; tk, hyoid bone, not joined to any other bone, except by 

 muscles; au, opening of ear ; /, lachrymal bone. A small part of 

 sphenoid bone is shown ; the main part is at base of skull. 



The eight cranial bones are : 

 . . r One Frontal (forehead). One Occipital (back and floor). 



Spongy TwQ Parietal (sides and roof). One Sphenoid (central floor). 



boneS 1S active Two Tem P ral (sides). One Ethmoid (front floor). 



in producing the red corpuscles found in the blood. 



