The extensor hallucis longus is a muscle that is located in the foot that assists with a specific type of movement, known as inversion. This muscle actually begins near the fibula and extends downward into the foot. In addition to allowing the foot to be turned inward, some of the other specific functions of the muscle are to help in the extension of the big toe as well as to allow the foot to move in such a direction as to have the toes pointing toward the leg.
There is only one muscle in the human body that is able to pull back, or extend, the big toe. This muscle is the extensor hallucis longus and it begins along the innermost surface of the front part of the fibula. The fibula is also popularly referred to as the calf bone. The muscle travels downward from the fibula into the foot, finally reaching its end at the big toe.
Dorsiflexion is the term given when this muscle causes the foot to move in an upward direction. Inversion is when the foot is moved in an inward, sideways direction. Besides extending the big toe, both dorsiflexion and inversion are made possible by the extensor hallucis longus.
The nerve supply to the muscle is provided by the peroneal nerve. This nerve is also known as the fibular nerve and it extends from the lower portion of the leg into the foot. It also provides the nerve supply to each of the toes.
Each of the movements made possible by the use of the extensor hallucis longus is important. However, one particular function of this muscle is most noticeable, as it aids in ambulation, or the ability to walk. This function is most important when walking up any type of step, particularly groups of stairs. The muscle allows the big toe to move in an upward direction in such a way that the foot is able to clear each individual stair during climbing.
Exercises such as toe raises are often beneficial in strengthening the extensor hallucis longus muscle. Shin stretches are also used to aid in its movement. When this muscle becomes weak, or if the surrounding tendons become injured or inflamed, medical attention is often required. A medical professional who specializes in sports medicine is often the best equipped to treat these specific types of injuries.