Objective To study the anatomy of the innervation of hallucis longus muscle,and discuss the clinical value of the innervation.Methods Nineteen limbs of 10 cadavers were studied.There were 4 female cadavers and 6 male cadavers.Nine were left legs and 10 were right legs.The specimens were anatomied to confirm the tibialis anterior,extensor digitorum longus and hallucis longus muscle.The innervation of hallucis longus muscle was been observed along the deep peroneal nerve.Measuring the muscular branches length (nerve length,NL),the distance from the tip of the fibular head to the muscular brance (nerve-fibula head length,NFL),and fibular length (fibula length,FL).The hematoxylin and eosin stain was used to observe the numbers of nerve fascicle for each branch of EHL.Results Twenty-three muscle branches of hallucis longus muscle were found in 19 limbs,15 limbs had a single branch,4 limbs had the double branches.All branches were originated in the deep peroneal nerve.Fourteen branches were into hallucis longus muscle from the fibular side,3 from anterior side,6 from the tibial side.The fibula length was 37.0±1.9 cm (range,34.5-40.6 cm); the nerve-fibula head length was 89.0±5.2 mm (range,75.4-97.2 mm);nerve length was 48.5±5.0 mm (range,33.6-57.4 mm); the nerve-fibula head length/fibula length was 0.245±0.020 (range,0.211-0.280).Among 15 specimens with single branch,3 branches had a unique nerve fascicle and 12 had two fascicles.Among 4 specimens with doulbe branches,only 1 branch had two fascicles,7 branches had a unique fascicle.Conclusion Special anatomical features of muscular branches might be the reason of isolated extensor hallucis longus dysfunction.