THE PEDAL BONE. 



29 



Fig. it. — Postero-lateral view of pedal l)one ; in this figure 

 the eutire upper surface is not visible. B, inner lateral 

 cartilase. 



shallow depressions. On the posterior edge of this surface is a 

 narrow elongated facet, to which the navicular bone is applied 

 (fig. 24). The lower or plantar surface (fig. 18) is slightly 

 concave, so that when the bone is resting on a plane only 

 the external margin 

 actually touches it. 

 This surface presents 

 two half-moon-shaped 

 portions, of which the 

 posterior is smaller 

 and thrust into the 

 anterior. The anterior 

 (fig. 18, a) is covered 

 by the sensitive sole 

 and is fairly smooth ; 

 at the back, however, 

 where the body of the 

 bone becomes continuous with the wings (fig. 1 8, b), it is rough 

 and full of holes. The posterior, and smaller, portion appears 

 as though cut out of the anterior ; and the border (fig. 18, c) 

 which divides it from the anterior part is rough for the insertion 

 of the flexor pedis perforans ten- 

 don. In the centre, close behind 

 this border, is a protuberance con- 

 sistino; of firm, bonv substance, 

 and serving for the insertion of a 

 ligament. 



On either side of this protuber- 

 ance is the mouth of a canal (fig. 

 16, d), the plantar foramen, from 



which a groove, termed the plantar fig. is.— inferior surface of pedal bone. 



•=• «, anterior portion covered in life by 



groove runs. These canals are sensitive sole ; 6, wing of pedal bone'.- 



o ' _ the part shown is retrossal process ; c, 



continued into the interior of the rough crescent-shaped portion for in- 

 sertion of flexor pedis perforans ; d, 



pedal bone and meet, forming a plantar groove leading to e, plantar 



^ , foramen. 



semicircle, from which are given 



off in various directions numerous small secondary canals. The 

 grooves, holes, and canals permit of tlie passage of blood-vessels 

 and nerves (compare fig. 38). 



The coronoid or pyramidal process, already mentioned, serves 

 for the insertion of the extensor pedis tendon. The two wings 



