Physiology of Balance
Brainstem – Vestibular nuclei are an essential processing station for information concerning balance. Brainstem disease very often gives rise to severe disturbances of posture
The proprioceptors in the muscles and joints send impulses to the brain in response to pressure, gravity and movement. Impulses from the cortex via the motor nerves to the muscles are essential in maintaining posture and balance.
The labyrinth is a complex balance organ in the inner ear. Highly specialized cells – neuroepithelial tissue – in the labyrinth respond to changes in movement of the head. These semicircular canals respond mainly to angular movement while the highly developed neuro-epithelium in the otolith organ responds mainly to linear movement. Disorders of the labyrinth frequently cause a sensation of spinning which the patient reports as vertigo or dizziness
The cerebellum is important in the control of fine movement and receives information from the vestibular nuclei and the cerebral cortex. Cerebellar disease typically causes severe unsteadiness and balance problems
The eye receives visual stimuli and constantly updates the nervous system about our position in relation to the environment. The ocular muscles can cause eye movement in response to stimuli from the vestibular nuclei and from the cortex so that, for example, we can focus on an object while the head is moving
The cortex is part of the brain that causes conscious awareness.
Signals from various parts of the body to the cortex help make us aware of where we are in space. Impulses from the cortex to the muscles help to maintain balance, for example, when we are on the move