OF THE FOOT AS A WHOLE. 



309 



about the seventh month : cuboid, at the ninth month ; external cuneiform, 

 during the first year : internal cuneiform in the third year ; middle cuneiform and 

 navicular in the fourth year. , The epiphysis for the posterior tuberosity of 



ysis. 



Appears 10th year ; 



unites after puberty. 



Tarsus. 



One centre /or each bone, 

 except os colds. 



Metatarsus. 



Tiro centres for each bone: 

 One for shaft. 

 One for digital extremity 

 except 1st. 



Appears 5th year. 

 Unite 18th-20 year. 



Appears 7th week. 



Appears 7th week. 



Unite 18th-gOth year. 

 Appears 3rd year. 



Appears 4^h year. 

 Unite 17-18th year. 



Phalanges. Appears 2nd-4th month.-l 

 Two centres for each bone : 

 One for shaft, 



One for metatarsal Appears 6th-7th year, 

 extremity. {-,/,, 27th-18th year. I 



Appears 2nd- 4th month. 



Appears 6th year. 



Unite 17th-18th year. 



Appears 7th ireek. 



FIG. 226. Plan of the development of the foot 



the os calcis appears at the tenth year, and unites with the rest of the bone soon 

 after puberty. 



The Metatarsal bones are each developed by two centres : one for the shaft 

 and one for the digital extremity in the four outer metatarsal ; one for the shaft 

 and one for the base in the metatarsal bone of the great toe. 1 Ossification 

 commences in the centre of the shaft about the ninth week, and extends toward 

 either extremity. The centre in the proximal end of the first metatarsal bone 

 appears about the third year, the centre in the distal end of the other bones 

 between the fifth and eighth years; they become joined between the eighteenth and 

 twentieth years. 



The Phalanges are developed by tico centres for each bone : one for the shaft 

 and one for the metatarsal extremity. 



Construction of the Foot as a Whole. 



The foot is constructed on the same principles as the hand, but modified to 

 form a firm basis of support for the rest of the body when in the erect position. It 



1 As was noted in the first metacarpal bone, so in the first metatarsal, there is often to be observed 

 a tendency to the formation of a second epiphysis in the distal extremity. (See footnote, p. 274). 



