What is the primary function of the gastrocnemius muscle?

The primary function of the gastrocnemius muscle is to plantar flex the foot and assist in flexing the knee. The gastrocnemius is a large muscle located in the calf, and its main role is to enable the action of pointing the toes away from the body, which is essential for activities such as walking, running, and jumping.

In addition to its role in plantar flexion, the gastrocnemius also crosses the knee joint, aiding in knee flexion when the foot is in a plantarflexed position. This dual function is crucial for the coordination of leg movements during various forms of activity.

The other choices do not accurately describe the primary actions of the gastrocnemius. Dorsiflexion, for instance, is primarily performed by the tibialis anterior muscle. Extending the leg is more commonly associated with the quadriceps muscle group at the knee. Adducting the foot does not pertain to the function of the gastrocnemius either, as foot adduction is typically addressed by other muscles. Therefore, the correct answer highlights the gastrocnemius's crucial contributions to both plantar flexion of the foot and assistance in knee flexion.