Which muscles produce plantarflexion of the ankle?

The muscles that are primarily responsible for plantarflexion of the ankle are indeed the gastrocnemius, soleus, plantaris, and posterior tibialis.

The gastrocnemius and soleus together make up the calf muscles, which are crucial for pushing the foot downwards. The gastrocnemius has two heads and crosses both the knee and ankle joints, producing powerful plantarflexion when the knee is extended. The soleus lies underneath the gastrocnemius and is particularly effective at plantarflexion when the knee is flexed because it does not cross the knee joint. The plantaris, although a small muscle, assists in the plantarflexion movement.

The posterior tibialis plays a supportive role by stabilizing the foot and contributing to the motion of plantarflexion, particularly when the foot is in a more inverted position.

The other options listed include muscles that are not primarily responsible for plantarflexion. For instance, the muscles in the first option are involved in dorsiflexion, while the quadriceps and hamstrings primarily act on the knee. Similarly, the muscles in the last option also do not contribute significantly to plantarflexion. Thus, recognizing the primary functions of these muscle groups highlights why the second option contains