THE FOOT 251 



prismoid form. The proximal extremity presents, as a rule, no lateral articular 

 facet, but occasionally on the outer side there is an oval facet by which it articulates 

 with the second metatarsal bones. Its proximal articular surface is of large 

 size and kidney-shaped; it corresponds to ihe distal extremity of the internal 

 cuneiform; its circumference is grooved, for the tarsometatarsal ligaments, and 

 internally gives attachment to part of the tendon of the Tibialis anticus muscle; 

 its inferior angle presents a rough oval prominence, the tuberosity (tuberositas 

 ossis metatarsalis I), for the insertion of the tendon of the Peroneus longus. The 

 head is of large size; on its plantar surface are two grooved facets, over which 

 glide sesamoid bones; the facets are separated by a smooth elevated ridge. 



This bone is known by the single kidney-shaped articular surface on its base, the deeply 

 grooved appearance of the plantar surface of its head, and its great thickness relatively to its 

 length. When it is placed in its natural position, the concave border of the kidney-shaped 

 articular surface on its base points to the side to which the bone belongs. 



Attachment of Muscles. To three part of the Tibialis anticus, the Peroneus longus, and 

 the First dorsal interosseous. 



The second metatarsal (os metatarsale II) (Fig. 202) is the longest and largest 

 of the remaining metatarsal bones, being prolonged backward into the recess 

 formed between the three cuneiform bones. Its tarsal extremity is broad above, 

 narrow and rough below. It presents four articular surfaces one behind, of 

 a triangular form, for articulation with the middle cuneiform; one at the upper 

 part of its internal lateral surface, for articulation with the internal cuneiform; 

 and two on its external lateral surface an upper and a lower, separated by 

 a rough nonarticular interval. Each of these articular surfaces is divided by a 

 vertical ridge into two facets, thus making four facets; the two anterior of these 

 articulate with the third metatarsal ; the two posterior (sometimes continuous) 

 with the external cuneiform. In addition to these articular surfaces there is 

 occasionally a fifth when this bone articulates with the first metatarsal bone. 

 It is oval in shape, and is situated on the inner side of the shaft near the base. 



The facets on the tarsal extremity of the second metatarsal bone serve at once to distinguish it 

 from the rest, and to indicate the foot to which it belongs; there being one facet at the upper 

 angle of the internal surface, and two facets, each subdivided into two parts, on the external 

 surface, pointing to the side to which the bone belongs. The fact that the two posterior subdi- 

 visions of these external facets sometimes run into one should not be forgotten. 



Attachment of Muscles. To four the Adductor obliquus hallucis, First and Second 

 dorsal interossei, and a slip from the tendon of the Tibialis posticus; occasionally also a slip 

 from the Peroneus longus. 



The third metatarsal (os metatarsale III) (Fig. 203) articulates proximally, 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 third metatarsal is known by possessing at its tarsal end two undivided facets on the inner 

 side, and a single facet on the outer. This distinguishes it from the second metatarsal, in which 

 the two facets, found on one side of its tarsal end, are each subdivided into two. The single facet 

 (when the bone is put in its natural position) is on the side to which the bone belongs. 



Attachment of Muscles. To five Adductor obliquus hallucis, Second and Third dorsal 

 and First plantar interossei, and a slip from the tendon of the Tibialis posticus. 



The fourth metatarsal (os metatarsale IV) (Fig. 204) is smaller in size than the 

 preceding; its tarsal extremity presents a terminal quadrilateral surface, for articu- 

 lation 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 



