308 THE SKELETON. , 



The projection on the outer side of this bone at its tarsal end at once distin- 

 guishes it from the others, and points to the side to which it belongs. 



Articulations. Each bone articulates with the tarsal bones by one extremity, 

 and by the other with the first row of phalanges. The number of tarsal bones 

 with which each metatarsal articulates is one for the first, three for the second, one 

 for the third, two for the fourth, and one for the fifth. 



Attachment of Muscles. To the first metatarsal bone, three : part of the 

 Tibialis anticus, the Peroneus longus, and First dorsal interosseous. To the 

 second, four : the Adductor obliquus hallucis and First and Second dorsal inter- 

 osseous, and a slip from the tendon of the Tibialis posticus, and occasionally a slip 

 from the Peroneus longus. To the third, five : the Adductor obliquus hallucis, 

 Second and Third dorsal, and First plantar interosseous, and a slip from the 

 tendon of the Tibialis posticus. To the fourth, five : the Adductor obliquus hallucis, 

 Third and Fourth dorsal, and Second plantar interosseous, and a slip from the 

 tendon of the Tibialis posticus. To the fifth, six : the Peroneus brevis, Peroneus 

 tertius, Flexor brevis minimi digiti, Adductor transversus hallucis, Fourth dorsal, 

 and Third plantar interosseous. 



The 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. 



The phalanges of the first row resemble closely those of the hand. The shaft 

 is compressed from side to side, convex above, concave below. The posterior 

 extremity is concave ; and the anterior extremity presents a trochlear surface, for 

 articulation with the second phalanges. 



The phalanges of the second row are remarkably small and short, but rather 

 broader than those of the first row. 



The ungual phalanges in form resemble those of the fingers ; but they are 

 smaller, flattened from above downward, presenting a broad base for articulation 

 with the second row, and an expanded extremity for the support of the nail and 

 end of the toe. 



Articulation. The first row, with the metatarsal bones behind and second 

 phalanges in front ; the second row of the four outer toes, with the first and third 

 phalanges ; of the great toe, with the first phalanx ; the third row of the four 

 outer toes, with the second phalanges. 



Attachment of Muscles. To the first phalanges. Great toe, five muscles : 

 innermost tendon of Extensor brevis digitorum, Abductor hallucis, Adductor 

 obliquus hallucis, Flexor brevis hallucis, Adductor transversus hallucis. Second 

 toe, three muscles : First and Second dorsal interosseous and First lumbrical. 

 Third toe, three muscles : Third dorsal and First plantar interosseous and Second 

 lumbrical. Fourth toe, three muscles : Fourth dorsal and Second plantar inter- 

 osseous and Third lumbrical. Fifth toe, four muscles : Flexor brevis minimi 

 digiti, Abductor minimi digiti, and Third plantar interosseous, and Fourth 

 lumbrical. Second phalanges. Great toe; Extensor longus hallucis, Flexor 

 longus hallucis. Other toes ; Flexor brevis digitorum, one slip of the common 

 tendon of the Extensor longus and brevis digitorum. 1 Third phalanges : two slips 

 from the common tendon of the Extensor longus and Extensor brevis digitorum, 

 and the Flexor longus digitorum. 



Development of the Foot (Fig. 226). 



The Tarsal bones are each developed by a single centre, excepting the os calcis, 

 which has an epiphysis for its posterior extremity. The centres make their appear- 

 ance in the following order : os calcis, at the sixth month of foetal life ; astragalus, 



1 Except the second phalanx of the fifth toe, which receives no slip from the Extensor brevis 

 digitorum. 



