METATARSAL BONES. 



97 



Fig. 38 * 



with the os calcis ; anterior,- of smaller size, divided by a ridge 

 into two facets, for the fourth and fifth metatarsal bones ; and 

 internal, a small oval articular facet, upon a large and quadran- 

 gular 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 back- 

 wards, 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 ; os calcis, external cuneiform, 

 and fourth and fifth metatarsal bones. 



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

 adductor pollicis, and flexor brevis minimi digiti. 



Upon a consideration of the tarsus it will be observed, that each 

 bone articulates with four adjoining bones, with the exception of 

 the os calcis, which articulates with two, and the external cunei- 

 form with six. 



Developement. By a single centre for each bone, with the ex- 

 ception of the os calcis, which has two centres of ossification ; the 

 second centre makes its appearance at about the ninth year, and is 

 not united with the preceding until the fifteenth. 



The METATARSAL BONES, jive in number, 

 are long bones, and divisible 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 pre- 

 sents a rounded head, circumscribed by a 

 neck, to articulate with the first row of pha- 

 langes. 



Peculiar Metatarsal Bones. The first is 

 shorter and larger than the rest, forming the 

 inner border of the foot; its posterior extre- 

 mity presents only one articular surface on 

 the side, and an oval rough surface upon a 

 prominent process beneath, for the insertion of 

 the tendon of the peroneus longus. The an- 

 terior 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- 



* The sole of the left loot. 1. The inner tuberosity of the os calcis. 2. The outer 

 tuberosity. 3. The groove for the tendon of the flexor longus digitorum. 4. The 

 rounded head of the astragalus. 5. The scaphoid bone. 6. Its tuberosity. 7. The 

 internal cuneiform bone ; its broad extremity. 8. The middle cuneiform bone. 9. 

 The external cuneiform bone. 10, 11. The cuboid bone. 11. Refers to the groove for 

 the tendon of the peroneus longus. 12, 12. The metatarsal bones. 13, 13. The first 

 phalanges. 14, 14. The second phalanges of the four lesser toes. 15, 15. The third, 

 or ungual phalanges of the four lesser toes. 16. The last phalanx of the great toe. 



13 



