College of Massage Therapists of British Columbia (CMTBC) Practice Exam

What is contained in the anterior compartment of the leg?

1. Extensor pollicis longus

2. Flexor hallucis longus

3. Extensor digitorum longus

4. Extensor digitorum

The correct answer is: Extensor digitorum longus

The anterior compartment of the leg is primarily responsible for dorsiflexion of the foot and extension of the toes. It contains several key muscles that facilitate these movements. Among these is the extensor digitorum longus, which specifically extends the lateral four toes and assists in dorsiflexion at the ankle. The extensor digitorum longus originates from the lateral condyle of the tibia and the interosseous membrane, and it runs down to attach to the toes. Its role in extending the toes makes it a significant muscle in the anterior compartment. On the other hand, the extensor pollicis longus is not part of the anterior leg compartment; it belongs to the posterior compartment of the forearm, and its primary function is to extend the thumb. Flexor hallucis longus is similarly located in the posterior compartment of the leg, primarily responsible for flexing the big toe. Extensor digitorum, while closely named to the extensor digitorum longus, refers to a different muscle—specifically, it's more common in the forearm and is not a primary muscle in the anterior compartment of the leg. Thus, the extensor digitorum longus is correctly identified as the muscle contained within