METATARSAL BONES. 105 



foot ; the inferior, marked by a prominent ridge, the tuberosity, and a 

 deep groove for the tendon of the peroneus longus ; and an external, 

 the smallest of the whole, and deeply notched by the commencement 

 of the peroneal groove. The articular surfaces are, the posterior, which 

 is of large size, and concavo-convex, to articulate with the os calcis ; 

 anterior, of smaller size, divided by a slight ridge into two facets, for 

 the fourth and fifth metatarsal bones ; and internal, a small oval articu- 

 lar 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/bwr bones; calcaneus, external cuneiform, and 

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



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

 tor 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 

 exception of the calcaneus, which articulates with two, and the exter- 

 nal 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 ; 

 astragalan, seventh month ; cuboid, tenth month ; external cuneiform, 

 during the first year ; internal cuneiform, during the third year ; 

 middle cuneiform and scaphoid, during the fourth year. The epiphysis 

 of the calcaneus appears" at the ninth year and is united with the dia- 

 physis at about the fifteenth. 



The METATARSAL BONES, five in number, are long bones, and divi- 

 sible therefore into a shaft and two extremities. The shaft is pris- 

 moid, 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, cir- 

 cumscribed 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 ex- 

 tremity 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 cunei- 

 form bones ; a large oval facet, but often no articular surface, on its 

 inner side, to articulate with the metatarsal bone of the great toe, and 

 two externally, for the third metatarsal bone. 



The third may be known by two facets upon the outer side of its 



