228 SKELETON. 



external face is somewhat concave, and presents, at its poste- 

 rior part, a vertical articular face for joining the cuneiforme 

 externum ; but anteriorly, it is rough for the origin of ligamen- 

 tous fibres. 



In the articulated foot the lower part of this bone is almost 

 concealed between the other two cuneiforms. 



Of the Cuneiforme Externum, (Troisieme Cuneiforme.') 



The external or third cuneiform bone is placed upon the sca- 

 phoides, between the second cuneiform and the cuboides. Of 

 the three bones it is the second in size, and is also appropriate- 

 ly named from its shape. The base is upwards. 



The posterior face furnishes, on its superior half to join the 

 scaphoides, a quadrangular articular facet, sloping outwardly, 

 below which the bone projects into the sole of the foot. The 

 anterior face is flat, and articulates with the third metatarsal 

 bone. The internal face presents, above, two articular facets, 

 of which the one at the posterior corner is larger than the other, 

 and joins the second cuneiform; the other, at the anterior cor- 

 ner, is very small, and touches the second metatarsal bone. 

 Below these facets the bone is rough, and gives origin to liga- 

 mentous matter. The external face, at the middle of the base, 

 forms an angular projection, behind which is a small oval arti- 

 cular surface that joins the cuboides. The remainder of this 

 face is rough, for the origin of the ligaments, with the excep- 

 tion of a very small articular facet at the anterior superior cor- 

 ner, which joins the fourth metatarsal bone. 



The structure of the bones of the Tarsus is uniformly cellu- 

 lar within, the cells being enclosed by a thin lamina of con- 

 densed matter. The astragalus is rather stronger and more 

 compact than any of the others. I have seen one instance, 

 however, in which it had been separated into two pieces by a 

 transverse vertical fracture, going from the ankle joint to the 

 articulation with the os calcis. The observation was made 

 after it had been boiled: the callus had completely united the 

 two fragments, and no displacement had occurred. 



