Final answer:
Muscles posterior to the medial malleoli are involved in plantar flexion, helping lower the foot and assisting in leg stabilization and rotation.
Step-by-step explanation:
The muscles that pass posterior to the medial malleoli are primarily involved in plantar flexion of the foot. This action is crucial for various activities such as pushing off during walking, standing on tiptoes, or foot-tapping. The posterior compartment of the leg, which includes both superficial and deep muscles, facilitates these actions. Particularly, the tibialis posterior muscle is responsible for plantar flexing and inverting the foot. Additionally, these muscles assist in the stabilization and movement of the back of the lower legs, such as when bringing the tibia/fibula up towards the buttocks or controlling rotation of the leg at the knee and thigh.
These muscles are responsible for various movements, including plantar flexion of the foot (lowering the sole of the foot to the ground) and assisting in moving the back of the lower leg up and back toward the buttocks. They also play a role in rotation of the leg at the knee and thigh. During activities that require lifting the heel off the ground, such as jumping, the posterior muscles are actively engaged to perform plantar flexion. Moreover, these muscles contribute to other functions, including adjusting the foot when catching balance, indicating their role in maintaining equilibrium and dynamic control during motion.