METATARSAL BONES. 



by a slight ridge into two facets, for the fourth and fifth metatarsal bones ; 

 and internal, a small oval articular facet, upon a large and quadrangular 

 surface, for the external cuneiform bone. 



If the bone be held so that the plantar surface, with the peroneal groove, 

 look downwards, and the largest articular surface backwards, the small 

 non-articular surface, marked by the deep notch, will point to the side 

 corresponding with the foot to which the bone belongs. 



Articulations. With four bones; calcaneus, external cuneiform, and 

 fourth and fifth metatarsal bones, sometimes also with the scaphoid. 



Attachment of Muscles. To three ; the flexor brevis pollicis, adductor 

 pollicis, and flexor brevis minimi digiti. 



Upon a consideration of the articulations of the tarsus it will be ob- 

 served, that each bone articulates with four adjoining bones, with the ex- 

 ception of the calcaneus, which articulates with two, and the external 

 cuneiform with six. 



Development. By a single centre for each bone, with the exception of 

 the os calcis, which has an epiphysis for its posterior tuberosity. The 

 centres appear in the following order : calcanean, sixth month ; astra- 

 galan, seventh month ; cuboid, tenth month ; external cuneiform, during 

 the first year ; internal cuneiform, during the third year ; middle cunei- 

 form and scaphoid, during the fourth year. The epiphysis of the calca- 

 neus appears at the ninth year, and is united with the diaphysis at about 

 the fifteenth. 



The METATARSAL BONES, Jive in number, are long bones, and divisible 

 therefore into a shaft and two extremities. The shaft is prismoid, and 

 compressed from side to side ; the posterior extremity, or base, is square- 

 shaped, to articulate with the tarsal bones, and with each other ; and the 

 anterior extremity presents a rounded head, circumscribed by a neck, to 

 articulate with the first row of phalanges. 



Peculiar Metatarsal Bones. The first is shorter and larger than the 

 rest, and forms part of the inner border of the foot ; its posterior extremity 

 presents only one lateral articular surface, and an oval rough prominence 

 beneath, for the insertion of the tendon of the peroneus longus. The 

 anterior extremity has, upon its plantar surface, two grooved facets, for 

 sesamoid bones. 



The second is the longest and largest of the remaining metatarsal bones ; 

 it presents at its base three articular facets, for the three cuneiform bones ; 

 a large oval facet, but often no articular surface, on its inner side, to arti- 

 culate with the metatarsal bone of the great toe, and two externally for 

 the third metatarsal bone. 



The third may be know r n by two facets upon the outer side of its base, 

 corresponding with the second, and may be distinguished by its smaller 

 size. 



The fourth may be distinguished by its smaller size, and by having a 

 single articular surface on each side of the base. 



The fifth is recognised by its broad base, and by its large tuberosity in 

 place of an articular surface upon its outer side. 



Development. Each bone by two centres; one for the body and one 

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

 the body, the other for the base in the metatarsal bone of the great toe 

 Ossific deposition appears in these bones at the same time with the vert<v 



