THE ANTERIOR CRURAL MUSCLES 





The Extensor hallucis longus (Extensor proprius 

 hallucis} is a thin muscle, situated between the 

 Tibialis anterior and the Extensor digitorum 

 longus. It arises from the anterior surface of the 

 fibula for about the middle two-fourths of its 

 extent, medial to the origin of the Extensor digi- 

 torum longus; it also arises from the interosseous 

 membrane to a similar extent. The anterior 

 tibial vessels and deep peroneal nerve lie between 

 it and the Tibialis anterior. The fibers pass 

 downward, and end in a tendon, which occupies 

 the anterior border of the muscle, passes through 

 a distinct compartment in the cruciate crural 

 ligament, crosses from the lateral to the medial 

 side of the anterior tibial vessels near the bend of 

 the ankle, and is inserted into the base of the distal 

 phalanx of the great toe. Opposite the metatarso- 

 phalangeal articulation, the tendon gives off a thin 

 prolongation on either side, to cover the surface 

 of the joint. An expansion from the medial side 

 of the tendon is usually inserted into the base of 

 the proximal phalanx. 



Variations. Occasionally united at its origin with the 

 Extensor digitorum longus. Extensor ossis metatarsi hal- 

 lucis, a small muscle, sometimes found as a slip from the 

 Extensor hallucis longus, or from the Tibialis anterior, or 

 from the Extensor digitorum longus, or as a distinct mus- 

 cle; it traverses the same compartment of the transverse 

 ligament with the Extensor hallucis longus. 



The Extensor digitorum longus is a penniform 

 muscle, situated at the lateral part of the front 

 of the leg. It arises from the lateral condyle of 

 the tibia; from the upper three-fourths of the 

 anterior surface of the body of the fibula; from 

 the upper part of the interosseous membrane; 

 from the deep surface of the fascia; and from the 

 intermuscular septa between it and the Tibialis 

 anterior on the medial, and the Peronsei on the 

 lateral side. Between it and the Tibialis anterior 

 are the upper portions of the anterior tibial vessels 

 and deep peroneal nerve. The tendon passes under 

 the transverse and cruciate crural ligaments in 

 company with the Peronseus tertius, and divides 

 into four slips, which run forward on the dorsum 

 of the foot, and are inserted into the second and 

 third phalanges of the four lesser toes. The ten- 

 dons to the second, third, and fourth toes are 

 each joined, opposite the metatarsophalangeal 

 articulation, on the lateral side by a tendon of 

 the Extensor digitorum brevis. The tendons are 

 inserted in the following manner: each receives a 

 fibrous expansion from the Interossei and Lum- 

 bricalis, and then spreads out into a broad apon- 

 eurosis, which covers the dorsal surface of the 

 31 



Fid. 437. Muscles of the front of 

 the leg. 



