ANATOMY. 



restricted to two directions, as in the hinge 

 of a door. 



The skeleton consists of an assemblage 

 of all the bones in the body, excepting the 

 os hyoides. It is said to be a natural ske- 

 leton, when the bones are connected by 

 means of their own ligaments or cartila- 

 ges ; an artificial one, when wire or 

 other extraneous substances are employ- 

 ed. 



It is divided into the head, trunk, and 

 extremities. 



The head consists of the cranium and 

 the face. The former of these parts con- 

 sists of 1 or 2 ossa frontis; 2 bssa parieta- 

 lia; 1 os sphenobasilare ; 2 ossa tempo- 

 rum ; 2 mallei ; 2 incudes ; 2 orbicularia ; 

 2 stapedes ; and 1 os jethmoideum : on 

 the whole, of 15 or 16 bones. 



The face has 2 ossa maxillaria superi- 

 ora; 2 ossa palati ; 2 ossa malae ; 2 ossa 

 nasi ; 2 ossa lacrymalia or uncuis ; 2 ossa 

 tiirbinata inferiora ; 1 osvomer; 1 max- 

 illa inferior ; 32 teeth; on the whole, 46 

 bones. 



The os hyoides consists of a body, 2 la- 

 teral portions called cornua, and 2 sural 

 processes called appendices. 



The bones of the head are therefore 61 

 r 62 ; with the os hyoides 66 or 67. 



In the neck there are 7 cervical verte- 

 brce : in the chest 12 dorsal vertebrae ; 24 

 ribs ; 2 or 3 bones of the sternum ; in the 

 loins 5 lumbar vertebra ; in the pelvis 1 

 sacrum, 4 ossa coccygis, 2 ossa innomi- 

 nata. 



Therefore the whole trunk has 57 or 58 

 bones. 



The shoulders have two clavicles, and 

 2 scapulae ; the arms 2 humeri ; the fore- 

 arms 2 ulnae and 2 radii ; the wrists 2 os- 

 sa scaphoidea ; 2 ossa lunaria ; 2 ossa 

 cuneiformia ; 2 ossa pisiformia; 2 ossa tra- 

 pezia : 2 ossa trapezioidea ; 2 ossa magna; 

 2 ossa unciformia ; the metacarpi 10 meta- 

 carpal bones; the fingers 10 posterior 

 phalanges, 8 middle phalanges, 10 ante- 

 rior phalanges, and 8 sesamoid bones. 



The bones of the upper extremities are 

 in the whole 72. 



The thighs have 2 femora; the legs 2 

 tibise, 2 patellae, and 2 fibulae; the tarsi 2 

 astragali, 2 ossa calcis, 2 ossa navicularia, 

 6 cuneiform bones, 2 ossa cuboidea; the 

 metatarsi 10 metatarsal bones ; the toes 

 10 posterior phalanges, 8 middle phalan- 

 ges, 10 anterior phalanges, and 6 sesamoid 

 bones. 



The bones of the lower extremities 

 are 66. 



The whole skeleton contains 259 or 261 

 bones. 



Of the bones just enumerated, the os 

 frontis, spheno-occipitale, ethmoideum, 

 vomer, inferior maxilla, the vertebrae, sa- 

 crum, and os coccygis, the bones of the 

 sternum, and the os linguale medium, or 

 body of the os hyoides, are single bones ; 

 and being placed in the middle of the bo- 

 dy, are consequently symmetrical. Of all 

 the other bones, there is a pair, consisting 1 

 of a bone for the right, and another for 

 the left side. 



The structure of the whole skeleton is 

 therefore symmetrical ; since an imagina- 

 ry perpendicular line drawn through the 

 whole would divide even the single bones 

 into a right and a left half, exactly resem- 

 bling each other. This observation must 

 however be taken with some allowance ; 

 since the corresponding bones of one side 

 are not always perfectly similar to those 

 of the opposite ; nor do the two halves of 

 the single bones always exactly agree in 

 form, &c. 



The entire natural skeleton of a man of 

 middle stature, in a dried state, weighs 

 from 150 to 200 ounces ; that of a woman 

 from 100 to 160 ounces. 



Jiones of the head. The cranium is the 

 oval bony cavity containing the brain ; 

 the face is placed at the anterior and low- 

 er part of this cavity, and holds some of 

 the organs of sense, and the instruments 

 of mastication. 



The bones of the head are joined by- 

 sutures, a mode of union nearly peculiar 

 to themselves ; hence, when all the soft 

 parts are destroyed by maceration, they 

 still remain most firmly connected to each 

 other, excepting the front teeth and the 

 lower jaw. The sutures are formed by 

 numerous sharp and ramified processes 

 of the opposed edges of the different 

 bones, shooting into corresponding vacui- 

 ties of each other. In some instances, 

 however, the bones seem to be joined by 

 the opposition of plane surfaces, and here 

 the union appears externally like a mere 

 line, instead of the irregular zigz.ig course 

 which it takes in the former case. The 

 last mentioned junction is called liar- 

 mo nia. 



In the fcetal state, the bones of the cra- 

 nium do not touch each other, but are 

 separated by considerable intervals of 

 membrane, and have thin extenuated 

 margins, which allow them to ride over 

 each other when subjected to pressure. 

 The larger and more conspicuous of these 

 intervals are called fontanelles, and allow 

 of the pulsation of the brain being felt in 

 a young subject. The importance of this 

 structure, in allowing the head to accom- 



