758 MAMMALIAN ANATOMY 



well defined for the mesocuneiform. The surface slopes in a plantar, 

 tibial, and proximal direction in nearly the same plane as the proximal 

 surface. 



Nomenclature. Entocuneiform is the Latin cuneiform, wedge- 

 shaped, with the Greek prefix ento, inner. Internal cuneiform is often 

 used as a synonym, which is the same as the German das innere Keil- 

 bein. Os cuneiforme primum is preferred by European anatomists. 

 The French use le premier cuneiforme. Comparative anatomists 

 designate the entocuneiform as tar sale I. 



FIG. 572. 



Dorsal Side. 



With Mesocuneiform. 



Distal Side. with First Proximal Side. 



M Scaphoid. 

 With Second Metatarsal. 



Plantar Side. 



LEFT ENTOCUNEIFORM, FIBULAR SURFACE. 



Determination. If the dorso-tibial surface be held upward and 

 the flat truncate distal surface toward the student, the straight side 

 will be on the side to which the bone belongs. 



Articulation. The entocuneiform articulates on the proximal 

 side with the scaphoid, on the fibular side with the mesocuneiform 

 and second metatarsal, and by its distal end with the rudimentary 

 first metatarsal. 



Muscular Attachments. The tibialis posticus is attached to the 

 entocuneiform. 



Ossification. The entocuneiform is developed from one centre. 



THE MESOCUNEIFORM. 



General Description. The Mesocuneiform is the smallest bone 

 in the tarsus. It lies distal to the scaphoid, proximal to the second 

 metatarsal, and wedged in between the other two cuneiforms in such 

 a way that it does not reach the plantar surface of the foot (Fig. 573). 

 It is nearly square, and somewhat prismatic ; it presents five surfaces, 

 the dorsal, the tibial, the fibular, the proximal, and the distal. 



The proximal surface (Fig. 574) may be distinguished from the 

 distal surface by its small size and its more regularly oval shape. Its 



