178 OSTEOLOGY. 



ment of each facet articulates with, the third metatarsal; the two posterior 

 sometimes continuous with the external cuneiform. 



The Third articulates behind, by means of a triangular smooth surface, with the 

 external cuneiform; on its inner side by two facets, with the second metatarsal; 

 and on its outer side, by a single facet, with the fourth metatarsal. The latter 

 facet is of circular form, and situated at the upper angle of the base. 



The Fourth is smaller in size than the preceding ; its tar sal extremity presents 

 ^a terminal quadrilateral surface, for articulation with the cuboid; a smooth facet on 

 the inner side, divided by a ridge into an anterior portion for articulation with the 

 third metatarsal, and a posterior portion for articulation with the external cunei- 

 form ; on the outer side a single facet, for articulation with the fifth metatarsal. 



The Fifth is recognized by the tubercular eminence on the outer side of its 

 base ; it articulates behind, by a triangular surface cut obliquely from without 

 inwards, with the cuboid ; and internally, with the fourth metatarsal. 



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, Peroneus longus, and First dorsal interosseous. To the second, three : the 

 Adductor pollicis, and First and Second dorsal interosseous. To the third, four : 

 the Adductor pollicis, Second and Third dorsal interosseous, and First plantar. 

 To the fourth, four : the Adductor pollicis, Third and Fourth dorsal, and Second 

 plantar interosseous. To the fifth, five : the Peroneus brevis, Peroneus tertius, 

 Flexor brevis minimi digiti, Fourth dorsal, interosseous and Third plantar inter- 

 osseous. 



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 downwards, 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. 



Articulations. The first row, with the metatarsal bones, and second phalanges ; 

 the second of the great toe, with the first phalanx, and of the other toes, with the 

 first and third phalanges ; the third, with the second row. 



Attachment of Muscles. To the first phalanges : Great toe ; innermost tendon of 

 ' Extensor brevis digitorum, Abductor pollicis, Adductor pollicis, Flexor brevis 

 pollicis, Transversus pedis. Second toe ; First and Second dorsal interosseous. 

 Third toe; Third dorsal and First plantar interosseous. Fourth toe; Fourth 

 dorsal and Second plantar interosseous. Fifth toe ; Flexor brevis minimi digiti, 

 Adductor minimi digiti, and Third plantar interosseous. Second phalanges: 

 Great toe ; Extensor longus pollicis, Flexor longus pollicis. Other toes ; Flexor 

 brevis digitorum, one slip from the Extensor brevis digitorum, and Extensor 

 longus digitorum. 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. 115.) 



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

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



