The term proprioception refers to the representation of the ongoing configuration of the body. Charles Sherrington originally coined the term to refer to the internal representation of the body based on signals from mechanoreceptors, including spindle receptors and Golgi tendon organs in muscles, receptors in the skin, and in internal tissues and organs. He also included under proprioceptive mechanisms the vestibular system, which provides information on the angular and linear accelerations (including gravity) acting on the body and on head orientation relative to gravity. When we move about and stand on earth, our locomotion and posture are controlled against the acceleration of gravity, which is pulling our body toward the surface of the earth. Muscle activity is necessary to maintain a posture or stance against ...