Extensor digitorum longus muscle

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Extensor digitorum longus muscle
Muscles of the front of the leg. (Extensor digitorum longus labeled at center left.)
Cross-section through middle of leg. (Extensores longi digitorum and et hallucis labeled at upper left.)
Latin musculus extensor digitorum longus
Gray's subject #129 481
Origin:
Insertion:
Blood:
Nerve: peroneal nerve
Action:
Dorlands/Elsevier m_22/12548912

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 Peronæi 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 Peronæus 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 tendons 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 Lumbricalis, and then spreads out into a broad aponeurosis, which covers the dorsal surface of the first phalanx: this aponeurosis, at the articulation of the first with the second phalanx, divides into three slips—an intermediate, which is inserted into the base of the second phalanx; and two collateral slips, which, after uniting on the dorsal surface of the second phalanx, are continued onward, to be inserted into the base of the third phalanx.

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[edit] Variations

This muscle varies considerably in the modes of origin and the arrangement of its various tendons.

The tendons to the second and fifth toes may be found doubled, or extra slips are given off from one or more tendons to their corresponding metatarsal bones, or to the short extensor, or to one of the interosseous muscles.

A slip to the great toe from the innermost tendon has been found.

[edit] Additional images

[edit] See also

[edit] External links

This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained herein may be outdated. Please edit the article if this is the case, and feel free to remove this notice when it is no longer relevant.

Muscles of the HeadNeckTrunkUpper limbLower limbLIST OF ALL MUSCLES

ILIAC REGION/HIP FLEXORS: psoas major | psoas minor | iliacus | (Gray's s127)

THIGH: anterior femoral | sartorius | quadriceps (rectus femoris, vastus lateralis, vastus intermedius, vastus medialis) | articularis genu
medial femoral/adductor | gracilis | pectineus | adductor brevis | adductor longus | adductor magnus
gluteal region | gluteals (maximus, medius, minimus) | tensor fasciae latae
lateral rotator group | piriformis | obturator externus | obturator internus | inferior gemellus | superior gemellus | quadratus femoris
posterior femoral/hamstring | biceps femoris | semitendinosus, semimembranosus | (Gray's s128)

LEG: anterior crural | tibialis anterior | extensor hallucis longus | extensor digitorum longus | fibularis tertius
superficial posterior crural | calf (gastrocnemius, soleus) | plantaris
deep posterior crural | popliteus | flexor hallucis longus | flexor digitorum longus | tibialis posterior
lateral crural | fibularis longus | fibularis brevis | (Gray's s129)

FOOT: dorsal | extensor digitorum brevis | extensor hallucis brevis
plantar first layer | abductor hallucis | flexor digitorum brevis | abductor digiti minimi
plantar second layer | quadratus plantae | lumbrical muscle
plantar third layer | flexor hallucis brevis | adductor hallucis | flexor digiti minimi brevis
plantar fourth layer | dorsal interossei | plantar interossei | (Gray's s131)

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