The extensor digitorum longus is a
pennate muscle, situated at the lateral part of the front of the leg.
Origin and insertion
It arises from the
lateral condyle of the
tibia
The tibia (; ), also known as the shinbone or shankbone, is the larger, stronger, and anterior (frontal) of the two bones in the leg below the knee in vertebrates (the other being the fibula, behind and to the outside of the tibia); it conn ...
; from the upper three-quarters of the anterior surface of the body of the
fibula
The fibula or calf bone is a leg bone on the lateral side of the tibia, to which it is connected above and below. It is the smaller of the two bones and, in proportion to its length, the most slender of all the long bones. Its upper extremity ...
; from the upper part of the
interosseous membrane
An interosseous membrane is a thick dense fibrous sheet of connective tissue that spans the space between two bones, forming a type of syndesmosis joint.
Interosseous membranes in the human body:
* Interosseous membrane of forearm
* Interosseous ...
; 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
Superior may refer to:
*Superior (hierarchy), something which is higher in a hierarchical structure of any kind
Places
*Superior (proposed U.S. state), an unsuccessful proposal for the Upper Peninsula of Michigan to form a separate state
*Lake ...
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 {{short description, Muscles between certain bones
Interossei refer to muscles between certain bones. There are many interossei in a human body. Specific interossei include:
On the hands
* Dorsal interossei muscles of the hand
* Palmar interosse ...
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
The extensor digitorum muscle (also known as extensor digitorum communis) is a muscle of the posterior forearm present in humans and other animals. It extends the medial four digits of the hand. Extensor digitorum is innervated by the posterior in ...
Additional Images
Extensor_digitorum_longus.png, Extensor digitorum longus muscle (in red)
Slide1ABBAA.JPG, Dorsum of Foot. Deep dissection.
Slide2ABBAA.JPG, Dorsum of Foot. Deep dissection.
Slide2WIKI.JPG, Ankle joint. Deep dissection. Lateral view.
References
External links
*
PTCentral
{{Authority control
Calf muscles
Muscles of the lower limb