Extensor Digitorum Longus (EDL) Anatomy

This muscle is present on the outer front of the lower leg. The name though sounds difficult but clearly defines the muscle. Extensor= muscle that extends, Digitorm= the digits of the foot (the small toes) and longus= because it is relatively longer than the other extensor of the digits.

Location:

It is present in the anterior compartment of lower leg and originates from both the lower leg bones tibia and fibula.

It arises from the upper end of tibia (lateral condyle), from the upper end and front surface of fibula and also from the membrane present between both these bones.

It travels downwards on the front of the lower leg and near the ankle turns into a tendon (white fibrous band of connective tissue that attaches a muscle to bone). This tendon further split into four parts, each of which runs towards the corresponding toe.

Each part inserts on the upper surface of the corresponding toe bones. Each small toe consists of three bones arranged in a line. These bones are called phalanges. The tendon inserts into the middle and end (present under the nail) phalanges.

Blood Supply:

Anterior tibial vessels

Nerve Supply:

Fibular (Peroneal) nerve

Movements:

  • When itcontracts, this muscle pulls all the small toes upwards i.e. extends the second, third, fourth and fifth toe.
  • It also twists the foot outwards (eversion of the foot).
  • It bends the ankle upwards (dorsiflexion of the ankle).

Functions:

This muscle extends the small toes while walking or while climbing stairs to help the toes avoid the steps.
Its action can also be noticed as one extends the toes to cut the nails.