630 A MANUAL OF ANATOMY. 



Action. To extend the foot upon the ankle, to adduct 

 the foot, to raise the inner border of the sole (inversion). 

 The action of this muscle tends to prevent the production 

 of flat foot by holding the tarsal bones firmly together, and 

 inverting the sole. 



Peroneus Longns. Figs. 123, 124, 134. 



Origin. From the external tuberosity of the tibia, from 

 the outer surface of the head and upper two-thirds of the 

 shaft of the fibula (lying posterior to the peroneus brevis), 

 from the intermuscular septa on either side, and from the 

 inner surface of the deep fascia in its upper third. 



Insertion (see Foot). The tendon of the muscle runs 

 behind the external malleolus (having the tendon of the 

 peroneus brevis in front), in front of the peroneal tubercle 

 on the os calcis, through the groove in the cuboid, across 

 the foot to the base of the first metatarsal bone and the 

 internal cuneiform. 



Behind the malleolus the two tendons have a common 

 synovial sheath, in the sole the long tendon has a special 

 one. A sesamoid bone is often found in the tendon as it 

 crosses the cuboid bone. 



Nerve Supply. The musculocutaneous which passes 

 through the muscle. 



Action. To extend the foot on the leg, to abduct the 

 fore part of the foot, to depress the ball of the great toe 

 (inner border of the foot) and raise the outer border of the 

 foot (producing eversion of the sole). It is an important 

 factor in maintaining the anteroposterior and transverse 

 arches of the foot and in walking. 



Peroneus Brevis. Figs. 123, 124. 



Origin. From the lower two-thirds of the outer surface 

 of the fibula, overlapping the peroneus longus for its lower 



