OF THE BONES. 359 



and the hyoid bone is still composed of at least three distinct 

 pieces. 



The following is an enumeration of the bones which most 

 anatomists agree in describing as distinct. 



Twenty-four moveable vertebra. 



Five pelvic vertebra^ united to form the sacrum or pelvic 

 bone. 



Three or four caudal vertebras, united to form the coccyx. 



Twelve ribs on each side; a single sternum, formed of three 

 distinct pieces in the adult. 



An occipital bone, a sphenoid bone, an ethmoid bone, a 

 frontal bone, two parietal bones, two temporal bones, each 

 containing three ossicula tympani; a vomer, two upper max- 

 illar bones, two palate bones, two zygomatic bones, two nasal 

 bones, two lachrymal bones or ossa unguis, two inferior tur- 

 binated bones, an inferior maxillar bone. 



A hyoid bone, composed, even in the adult, of three or five 

 distinct pieces. 



The bones, which remain to be enumerated, are all paired, 

 or double, and are those of the limbs or extremities; viz. 



The scapula, the clavicle, the humerus, the radius, the ulna, 

 the eight bones of the carpus, the five of the metacarpus, the 

 two phalanges of the thumb, the three phalanges of each of 

 the other fingers, and five sesamoid bones. 



The coxal bone, the femur, the tibia and patella, the fibula, 

 the seven bones of the tarsus, the five bones of the metatarsus, 

 the two bones of the great toe, the three bones of each of the 

 other toes, and three sesamoid bones. 



572. The situation of the bones is always internal, or deep. 

 Whether they form cavities for the nervous and vascular cen- 

 tres, or form the limbs, they are all covered by the muscles 

 and the teguments; none of them being external. 



573. The bones vary greatly as to size, some being a fourth, 

 fifth, or sixth of the length of the body, while others have 

 scarcely a diameter of a few lines. With reference to size, 

 the bones are divided into large, middle sized, small, and ve- 

 ry small, or ossicula. 



574. The form of the bones is symmetrical; Some are 

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