Tundra. The tundra is a treeless polar desert found in the high latitudes in the polar regions, primarily in Alaska, Canada, Russia, Greenland, Iceland, and Scandinavia, as well as sub-Antarctic islands.
The muscles acting on the foot can be divided into two distinct groups; extrinsic and intrinsic muscles. 1  The extrinsic muscles arise from the anterior, posterior and lateral compartments of the leg.2  They are mainly responsible for actions such as eversion, inversion, plantarflexion and dorsiflexion of the foot. The extrinsic muscles arise from the anterior, posterior and lateral compartments of the leg. 2  They are mainly responsible for actions such as eversion, inversion, plantarflexion and dorsiflexion of the foot.
The muscles that make up your calf -- including the gastrocnemius and soleus muscles -- are responsible for plantar flexion of the foot, or movement of the foot away from your shin. When you rise onto the balls of your feet, your calves contract to lift your heels off the floor. Walking on your toes takes it a step further -- literally. As you walk with your heels lifted, your calves remain active, helping you stay upright as they propel you across the floor.