THE LEG. 221 



The body of the fibula extends between its extremities. It is 

 irregularly triangular, somewhat smaller above than below, 

 thick posteriorly, thin anteriorly, and slightly convex in its 

 length behind. 



There are three faces to the fibula, one is external, another 

 internal, and the third posterior. The first is semi-spiral, and 

 turned forwards above; its superior third gives origin to the pe- 

 roneus longus muscle, .and the middle third to the peroneus se- 

 cundus: its lower third exhibits the semi-spiral arrangement 

 which may be traced into the groove on the posterior part of the 

 malleolus externus, and thereby indicates the course of the ten- 

 dons of these peronei muscles. The internal face is directed to- 

 wards the tibia ; it is divided by a low longitudinal ridge into 

 two parts, of which the anterior is the more narrow. The ridge 

 itself, well marked in the middle two-fourths of the bone, is in- 

 distinct above and below; and furnishes attachment to the inter- 

 osseous ligament. The space in front gives origin to the exten- 

 sor proprius pollicis, and the extensor communis digitorum : and 

 the space behind gives origin to the tibialis posticus. The pos- 

 terior face is also somewhat semi-spiral, its superior end being 

 outwards, and the inferior end inwards. The superior third gives 

 origin to the soleus muscle, and the remainder to the flexor lon- 

 pollicis pedis. 



The angles of the fibula which are formed by the junction of 

 the three surfaces described, differ somewhat among themselves. 

 The anterior angle is frequently very sharp and elevated in its 

 middle half, and below it bifurcates into two ridges, including 

 between them a triangular space, which is only covered by the 

 integuments. The posterior angle is well marked, and winds 

 so as to be external above, and posterior near the foot. The 

 internal angle, formed by the union of the internal and the pos- 

 terior surfaces, is only very well marked in its middle half. 

 The projection of this angle gives to the bone the appearance 

 of inclining inwards towards the tibia, besides which it has ac- 

 tually a little bend in that direction. 



Near the middle of the posterior face of the fibula, a canal, 

 sloping downwards, conducts the nutritious artery. The circum- 



19* 



