CHAP. IV.] 



THE SKELETON. 



33 



muscles of the calf of the leg. There are seven tarsal bones 

 in each ankle. (The names of the carpal and tarsal bones are 

 supplied in the table of the bones at the end of the chapter.) 



The metatarsus is formed by five bones. These metatarsal 

 bones closely resemble the metacarpal bones of the hand. Each 

 bone articulates with the tarsal bones 

 by one extremity, and by the other 

 with the first row of phalanges. 



The phalanges of the foot, both in 

 number and general arrangement, 

 resemble those in the hand, there 

 being two in the great toe and three 

 in each of the other toes. 



Bones of the cranium : 



Occipital 1 



Parietal 2 



Frontal 1 



Temporal 2 



Sphenoid 1 



Ethmoid 1 



8 



The occipital bone is situated at 

 the back and base of the skull. At 

 birth the bone consists of four parts, 

 which do not unite into a single bone 

 until about the sixth year. The in- 

 ternal surface is deeply concave, and 

 presents many eminences and de- 

 pressions for the reception of parts 

 of the brain. There is a large 

 hole the foramen magnum in 

 the inferior portion of the bone, for 

 the transmission of the medulla oblongata, the constricted por- 

 tion of the brain where it narrows down to join the spinal cord. 



The parietal bones (paries, a wall) form by their union the 

 greater part of the sides and roof of the skull. The external 

 surface is convex and smooth ; the internal surface is con- 

 cave, and presents eminences and depressions for lodging the 

 convolutions of the brain, and numerous furrows for the rami- 

 fications of arteries. 



FIG. 24. BONES OF THE 

 ANKLE AND FOOT. ra, meta- 

 tarsal bones; p, phalanges; ca, 

 os calcis, or heel bone. 



