274 INFERIOR EXTREMITY 



M. Peronseus Longus. The peronaeus longus muscle 

 arises from the head and from the lateral surface of the shaft 

 of the fibula in its proximal two-thirds. A surface of origin is 

 also afforded to it by the fascia which covers it, and by the 

 two peroneal intermuscular septa. It ends, a short distance 

 proximal to the ankle, in a long tendon, which is continued 

 distally posterior to the lateral malleolus. Gaining the lateral 

 margin of the foot, it proceeds forwards on the lateral surface 

 of the calcaneus to the groove on the plantar surface of the 

 cuboid, which conducts it transversely into the sole. Its 

 insertion will be examined at a later period. It is supplied 

 by the superficial peroneal nerve (O.T. musculo cutaneous], 



M. Peronseus Brevis. This muscle arises from the distal 

 two-thirds of the lateral surface of the body of the fibula, 

 distal and anterior to the peronaeus longus, and from the 

 peroneal intermuscular septum on either side of it. Its 

 tendon descends, posterior to the lateral malleolus, and then 

 turns forwards on the lateral surface of the calcaneus to gain 

 an insertion into the projecting base of the metatarsal bone 

 of the little toe. 1 On the posterior surface of the lateral 

 malleolus the tendon of the peronaeus brevis lies directly 

 under cover of the tendon of the peronaeus longus, and 

 therefore in contact with the bone. On the lateral surface of 

 the calcaneus the tendon of the peronaeus brevis is placed 

 more proxirnally than that of its fellow muscle. 



As the tendons of the two peronei muscles proceed 

 distally, in the hollow between the lateral malleolus and the 

 posterior prominence of the calcaneus, they are held in place 

 by the superior peroneal retinaculum, and their movements are 

 facilitated by the presence of a common mucous sheath. On 

 the lateral surface of the calcaneus the tendons are retained 

 in position by the inferior peroneal retinaculum^ but each tendon 

 lies in a separate compartment surrounded by its own special 

 prolongation of the mucous sheath. The peroneal tubercle 

 of the calcaneus intervenes between these two sheaths. The 

 peronaeus brevis is supplied by the superficial peroneal nerve. 



N. Peronaeus Communis (O.T. External Popliteal Nerve). 

 This nerve has previously been traced as far as the neck of 

 the fibula. At this point it disappears from view by passing 



1 A small tendinous slip will, as a general rule, be observed to proceed 

 forwards from the tendon of the peronaeus brevis to join the tendon of the long 

 extensor on the dorsum of the little toe. This is the peronccus quinti digiti. 



