SITUATION OF BONES. 51 



For the Trunk Twenty-four true or moveable vertebrae, one 

 sacrum, four caudal vertebra? or bones of the coccyx, two inno- 

 minata, twelve ribs on each side ; a sternum, in three pieces, 

 however, in the youthful adult: 



One hyoid, in three pieces, sometimes five in the adult, and 

 situated in the throat: ^ *^ 



The remaining bones compose the limbs, and are, therefore, 

 in pairs, or correspond exactly on the two sides of the body. 

 They are, 



For the upper Extremities The clavicle, the scapula, the os 

 humeri, the radius, the ulna, the eight bones of the carpus, the 

 five bones of the metacarpus, the two phalanges of the thumb, 

 the three phalanges of each of the fingers, the two, and some- 

 times more, sesamoid bones: 



For the lower Extremities The os femoris, the tibia, the fibula, 

 the patella, the seven bones of the tarsus, the five of the meta- 

 tarsus, the two phalanges of the big toe, the three phalanges of 

 each of the smaller toes, and the two, sometimes more, sesa- 

 moids. 



There are, therefore, twenty-two bones to the head, not in- 

 cluding those of the tympanum; fifty-six to the trunk of the 

 body ; one insulated bone to the throat; sixty-eight to the two 

 upper limbs; and sixty-four to the two lower limbs. In all, two 

 hundred and eleven. The redundancy or the deficiency of the 

 sesamoid bones, in a subject, may cause this number to be 

 slightly increased or diminished. 



The situation of the bones varies; some are profound, while 

 others approach very near to the surface of the body. They 

 are, as stated, either symmetrical, that is, consist of two late- 

 ral portions precisely alike, or else in pairs, having a perfect 

 correspondence with each other. The symmetrical or bilateral 

 bones are the frontal, the occipital, the sphenoidal, the ethmoidal, 

 the vomer, the inferior maxillary, the hyoid, the spinal, and the 

 sternal ; and they are situated under the middle vertical line of 

 the body. The pairs are on the sides of the middle line, more 

 or less removed from it. 



The long bones (ossalonga) are generally cylindrical or pris- 

 matic, and have their extremities enlarged for the purpose of 

 articulating with adjoining bones. The broad bones (ossa lata) 



