PERONEI MUSCLES. 633 



The recurrent articular branch is small, and takes the course of the 

 artery of the same name through the tibialis anticus muscle to the knee 

 joint. 



The musculo-cutaneous nerve is continued between the extensor longus 

 digitorum and the peronei muscles to the lower third of the leg, where it 

 pierces the fascia, and is distributed to the dorsum of the foot and the toes 

 (p. 626). Before the nerve becomes cutaneous it furnishes branches to 

 the two larger peronei muscles. 



The anterior tibial nerve (fig. 215) (interosseous) is directed beneath the 

 extensor longus digitorum, and reaches the tibial artery about the middle 

 third of the leg. From this spot it takes the course of the vessel along 

 the foot to the first interosseous space (p. 627). In the leg it crosses the 

 anterior tibial vessels once or more, but on the foot it is generally external 

 to the dorsal artery. 



Branches. In the leg the nerve supplies the anterior tibial muscle, the 

 extensors of the toes, and the peroneus tertius. On the dorsum of the foot 

 it furnishes a considerable branch to the short extensor ; this is enlarged, 

 and gives offsets to the articulations of the foot. 



MUSCLES ON THE OUTER PART OF THE LEG (fig. 209). Two muscles 

 occupy this situation, and are named peronei from their attachment to the 

 fibula ; they are distinguished by the terms longus and brevis. Intermus- 

 cular processes of fascia, which are attached to the fibula, isolate these 

 muscles from others. 



The PERONEUS LONGUS (fig. 209, ), the more superficial of the two 

 muscles, passes into the sole of the foot round the outer border. It arises 

 from the head, and the anterior surface of the shaft of the fibula for two- 

 thirds of the length, gradually tapering downwards ; from the external 

 border nearly to the malleolus ; and from the fascia and the intermuscular 

 septa. Inferiorly it ends in a tendon which is continued through the ex- 

 ternal annular ligament, with the peroneus brevis, lying in the groove at 

 the back of the external malleolus ; and it passes finally in a separate 

 sheath, below the peroneus brevis along the side of the calcis and through 

 the groove in the outer border of the cuboid bone, to the sole of the foot. 

 Its position in the foot, and its insertion are described before (p. 625). 



In the leg the muscle is immediately beneath the fascia, and lies on the 

 peroneus brevis. Beneath the annular ligament it is placed over the 

 middle piece of the external lateral ligament of the ankle with the peroneus 

 brevis, and is surrounded by a single synovial membrane common to both. 

 The extensor longus digitorum and the soleus are fixed to the fibula late- 

 rally with respect to it, one being on each side. 



Action. With the foot free the muscle extends the ankle : then it can 

 depress the inner, and raise the outer border of the foot in the movement 

 of eversion. 



When the foot rests on the ground it assists to lift the os calcis, and the 

 weight of the body as in standing on the toes, or in walking. And in 

 rising from a stooping posture it draws back the fibula. 



The PERONEUS BREVIS (fig. 209, H ) reaches the outer side of the foot, 

 and is smaller than the preceding muscle, and inferior in position to it. 

 It arises from the anterior surface of the shaft of the fibula for about the 

 lower two-thirds, extending upwards by a pointed piece internal to the 

 other peroneus ; and from the intermuscular septum in front. Its tendon 

 passes with that of the peroneus longus through the external annular liga- 

 ment, and is placed next the fibula as it turns below this bone. Escaped 



