366 Anatomy Applied to Medicine and Surgery. 



the fibula and from the interosseous membrane ; into the 

 ligamentous structures at the back and sides of the meta- 

 tarso-phalangeal articulation and into the base of the last 

 phalanx of the great toe. Action. To extend the first 

 phalanx of the great toe; to slightly extend the second 

 phalanx; to flex the ankle and at the same time slightly 

 adduct the front of the foot and invert the sole. Exten- 

 sor longus digitorum. From the upper three-fourths of 

 the anterior surface of the fibula and from the interosseous 

 membrane; into the metatarso-phalangeal joints and the 

 three phalanges of each of the four outer toes. Action. 

 To extend the first phalanges of these toes. It, may, to a 

 very slight degree, extend the second and third phalanges, 

 but the chief extension movement of these phalanges is 

 performed by the lumbricales and the interossei of the sole 

 of the foot, which are inserted into the expansions of this 

 tendon going to these phalanges. This muscle also flexes 

 the ankle joint and slightly everts and abducts the front 

 part of the foot. Peroneus tertius. From the lower 

 fourth of the anterior surface of the fibula and from the 

 interosseous membrane ; into the inner side of the base of 

 the metatarsal bone of the little toe. Action. It flexes 

 the ankle joint and abducts the front of the foot, at the 

 same time elevating the outer border of the foot. These 

 muscles have actions somewhat similar (flexion of the 

 foot, especially), and are all supplied by the same nerve, 

 viz., the anterior tibial. 



Anterior annular ligament. The vertical part of 

 this ligament binds down the tendons as they pass 

 to the foot, and is attached, externally, to the 

 lower end of the fibula and, internally, to the tibia. The 

 horizontal part will be considered in connection with the 

 dorsum of the foot. The vertical part contains one syn- 

 :>vial sheath, viz., that for the tibialis anticus tendon. The 



