Extensor digitorum longus muscle

3⁄4 of interosseous membraneInsertionDorsal surface; middle and distal phalanges of lateral four digitsArteryanterior tibial arteryNervedeep fibular nerveActionsextension of toes and dorsiflexion of ankleAntagonistFlexor digitorum longus, Flexor digitorum brevisIdentifiersLatinmusculus extensor digitorum longusTA98A04.7.02.038TA22645FMA22534Anatomical terms of muscle

The extensor digitorum longus is a pennate muscle, situated at the lateral part of the front of the leg.

Structure

It arises from the lateral condyle of the tibia; from the upper three-quarters 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 peroneal muscles on the lateral side. Between it and the tibialis anterior are the upper portions of the anterior tibial vessels and deep peroneal nerve.

The muscle passes under the superior and inferior extensor retinaculum of foot in company with the fibularis 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 articulations, 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 lumbricals, 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.

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.

See also

• Extensor digitorum brevis muscle
• Extensor digitorum muscle

Additional Images

• 
  Extensor digitorum longus muscle (in red)
• 
  Dorsum of Foot. Deep dissection.
• 
  Dorsum of Foot. Deep dissection.
• 
  Ankle joint. Deep dissection. Lateral view.

References

This article incorporates text in the public domain from page 481 of the 20th edition of Gray's Anatomy (1918)

External links

Iliac regionButtocks

Gluteal muscles maximus medius minimus tensor fasciae latae
lateral rotator group:	quadratus femoris inferior gemellus superior gemellus internal obturator external obturator piriformis

Thigh /
compartments

Anterior	sartorius quadriceps rectus femoris vastus lateralis vastus intermedius vastus medialis articularis genus
Posterior	hamstring biceps femoris semitendinosus semimembranosus
Medial	pectineus external obturator gracilis adductor longus brevis magnus minimus
Fascia	Femoral sheath Femoral canal Femoral ring Adductor canal Adductor hiatus Muscular lacuna fascia lata Iliotibial tract Lateral intermuscular septum of thigh Medial intermuscular septum of thigh Cribriform fascia

Leg/
compartments

Anterior	tibialis anterior extensor hallucis longus extensor digitorum longus fibularis (peroneus) tertius
Posterior	superficial triceps surae gastrocnemius soleus accessory soleus Achilles tendon plantaris deep tarsal tunnel flexor hallucis longus flexor digitorum longus tibialis posterior popliteus
Lateral	Fibularis (peroneus) muscles longus brevis
Fascia	Pes anserinus Intermuscular septa anterior posterior transverse

Foot

Dorsal	extensor hallucis brevis extensor digitorum brevis
Plantar	1st layer abductor hallucis flexor digitorum brevis abductor digiti minimi 2nd layer quadratus plantae lumbrical muscle 3rd layer flexor hallucis brevis adductor hallucis flexor digiti minimi brevis 4th layer dorsal interossei plantar interossei
Fascia	Plantar fascia retinacula Peroneal Inferior extensor Superior extensor Flexor