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THE MUSCULAR SYSTEM. 



The tendon of the muscle is inserted into the dorsal aspect of the base of the 

 fifth metatarsal bone. 



Nerve-Supply. Deep peroneal nerve (L. 4. 5. S. 1.). 



Actions. The muscle dorsi-flexes the ankle and raises the lateral border of the foot (as in 

 skating or dancing). 



M. Extensor Hallucis Longus. The extensor hallucis longus arises from 



the anterior part of the medial surface of the 

 fibula in its middle three -fifths, medial to 

 the origin of the extensor digitorum lougus, 

 and for a corresponding extent from the 

 interosseous membrane. Its tendon passes 

 over the dorsum of the foot, to be inserted 

 into the base of the terminal phalanx of the 

 great toe. 



The extensor primi internodii longus and 

 extensor ossis metatarsi hallucis are occasional 

 separate slips of this muscle inserted into the proximal 

 phalanx and the metatarsal bone. 



Nerve-Supply. Deep peroneal nerve (L.4. 5. S. 1.). 



Actions. This muscle dorsi-flexes the ankle, and 

 extends the great toe. t 



M. Extensor Digitorum Brevis. The 

 extensor digitorum brevis arises, on the 

 dorsum of the foot, from a special impression 

 on the dorsal surface of the calcaneus, and 

 from the deep surface of the ligamentum 

 cruciatum cruris. 



It usually gives rise to four fleshy bellies, 

 from which narrow tendons are directed for- 

 wards and medially, to be inserted into the 

 four medial toes. The three lateral tendons 

 join those of the long extensor muscle to form 

 the membranous expansions on the dorsum 

 of the toes. The most medial tendon (ex- 

 tensor hallucis brevis) is inserted separately 

 into the base of the first phalanx of the great 

 toe. 



Nerve -Supply. Deep peroneal nerve (L. 4. 5. 

 S. L). 



Actions. Extension of the four medial toes. 



The Muscles on the Lateral 

 Side of the Leg. 



These muscles comprise the peronsei, 

 longus and brevis. They are placed on the 

 lateral side of the leg between the extensor 

 digitorum longus in front, and the soleus and 

 flexor hallucis longus behind, enclosed in a 

 special compartment of the deep fascia. 



M. Peronseus Longus. The peronseus 

 longus arises from the head and the proximal 

 two-thirds of the lateral surface of. the body 

 of the fibula, from intermuscular septa on either side, and from the fascia over it. 



It forms a stout tendon, which lies superficial to the peronseus brevis, hooks 

 round the lateral malleolus deep to the peroneal retinaculum, crosses the lateral side 

 of the calcaneus, and, passing through a groove on the cuboid bone, is directed across 

 the sole of the foot to be inserted into the lateral sides of the first cuneiform and the 



PEBON^US BREVIS 



Ligamentum cruci- 

 atum cruris 



TENDON OF PERON^US 



TERTIUS 

 MOST MEDIAL SLIP OF 



EXTENSOR DIGITORUM 

 BREVIS (EXTENSOR 

 HALLUOIS BREVIS) 



FIG 380 MU OF TH 

 RIGHT LEG AND DOM OF 



