OSTEOLOGY OF THE HOR8E. 59 



and nerves in and out of the interior of the bone. The porosities 

 serve mostly for the fibrous attachment of the laminae. 



The inferior or circumj'erent edge of the wall is rather semi-oval 

 than semicircular. It is notched or serrated, particularly towards 

 the sides, where, in places, the notches opposite to the foramina 

 widen into gaps, in order to give passage to blood-vessels to the 

 sole. This edge, in its natural and healthy state, maintains at 

 every point the level of a plane surface. — Superiorly, in the mid- 

 dle, the wall is surmounted by the coronal process, from whose 

 sides sharp waving edges run to the wings, forming the bounda- 

 ries between it and the articulatory surface. 



The sole exhibits a broad, uniform, concave surface, of the 

 figure of a horseshoe, free from asperities, excepting towards the 

 wings. Still, however, it possesses porosities, or at least shows 

 the marks of the fibrous implantation of the sensitive sole. It is 

 bounded, anteriorly and laterally, by the circumferent edge of the 

 wall ; posteriorly, by a sharp, uneven, semicircular edge, which 

 divides it from the tendinous surface. 



The tendinous surface has a semicircular shape. It is 

 placed immediately behind the sole, and exhibits — 1st. A rough 

 depression in its fore and middle part, marking the insertion of the 

 tendo perforans. 2dly. Two lateral grooves, passing obliquely 

 inwards, and terminating each in a large foramen. 3dly. A porous 

 space intermediate between the two former divisions, into which 

 is fixed the inferior navicular ligament. The grooves lodge the 

 trunks of the arteries and nerves of the foot, which pass through 

 the foramina into the interior of the bone. 



The articulatory surface occupies the superior part. 

 It is half-moon- shaped. It presents two lateral cups, extending 

 angularly backwards as far as the wings, with a broad eminence 

 running transversely between them, which rises so gently as to be 

 more perceptible to the finger than the eye. This eminence is 

 terminated in front by the coronal process, having an incurva- 

 tion backwards : behind it, the surface is bevelled off, to which 

 part is opposed the navicular bone. The articular cavities for the 

 coronet bone are deepened by the sharp prominent edge running 

 around their front and sides. 



The al(z or wings consist of two bifid protuberances, stretch- 

 ing backwards from the body, beyond the limits of the articula- 

 tory surface. The lower and larger division of the ala, projecting 

 directly backwards, is irregular and asperous : to it is attached 

 the cartilage of the foot. The upper portions are tubercular and 

 smooth on their surface: to these are fixed the first pair of the 

 coffin ligaments. Between these divisions of the ala is a notch : 

 (which in the recent subject becomes a perfect foramen ;) ihiougli 



