The Anatomy of the Lower Leg Muscles

Many different muscles are located in the lower leg between the knee and the ankle. Some of the main ones include:

• Gastrocnemius, in the calf muscle
• Soleus, in the calf muscle
• Anterior tibialis, in front of the shin
  

This article describes the anatomy of the lower leg muscles. It covers where they're located and what they do.

Anatomy of the Lower Leg

Your muscles in the lower leg are supported by two very strong, long bones: the fibula and the tibia (shinbone). The tibia is stronger and more prominent than the fibula. It is located toward the middle of the lower leg. The fibula, or calf bone, is smaller and located on the lower leg's outside.

The lower leg is also home to nerve fibers, including the superficial fibular (or superficial peroneal) nerve, the deep fibular (or deep peroneal) nerve, and the tibial nerve. The primary muscle in this part of the body is the gastrocnemius, which gives the calf its signature bulging, muscular appearance.

The anterior tibial, posterior tibial, and fibular arteries are responsible for blood supply to the lower leg. The lower leg makes up a large portion of an individual's overall body weight. It is an essential structure for any weight-bearing activity, such as walking, standing, running, or jumping.

Common conditions that affect the lower leg include stress fractures, compartment syndrome, shin splints, and muscle tears.

Muscles of the Lower Leg

The lower leg is divided into four compartments that contain the various muscles of the lower leg—anterior, lateral, posterior and deep posterior.

Anterior Compartment

The anterior compartment, in the front of the shin, holds the tibialis anterior, the extensor digitorum longus, the extensor hallucis longus, and the peroneus tertius muscles. These muscles pull the toes and feet upward, a process known as dorsiflexion.

The tibialis anterior also assists in turning the foot inward. You can feel these muscles contract by placing your hand just to the outside of the tibia and pulling your foot up.

Lateral Compartment

The lateral compartment is along the outside of the lower leg. It contains the peroneus longus and peroneus brevis muscles. These muscles pull the toes and feet outward. They also help with pointing the foot, or plantar flexion. To feel these muscles contract, place your hand on the outside of your shin and turn your foot out.

Posterior Compartment

The posterior compartment holds the large muscles that we know as the calf muscles—the gastrocnemius and soleus. This compartment also contains the plantaris muscle.

The gastrocnemius is shorter, thicker and has two inner and outer attachments. It is the most visible of the calf muscles. The soleus lies underneath. These three muscles attach to the Achilles tendon, and they all aid with plantar flexion.

Deep Posterior Compartment

The deep posterior compartment lies deep within the back of the lower leg. It includes the tibialis posterior, the flexor digitorum longus and the flexor hallucis longus.

The tibialis posterior pulls the foot inward, the flexor digitorum longus flexes the toes, and the flexor hallucis longus flexes the big toe. All three aid in plantar flexion.