The ability to remain upright and move without falling over. Information on body position is relayed to the brain by many parts of the body: the eyes; proprioceptors (sense organs) in the skin, muscle, and joints; and the labyrinth of the inner ear. The cerebellum (part of the brain) integrates the information and sends instructions to enable various parts of the body to perform adjustments needed to maintain balance. Disorders affecting the ear, brain, or spinal cord commonly affect balance. Ear disorders include labyrinthitis and Ménière’s disease. Less commonly, otitis media may affect balance. Damage to nerve tracts in the spinal cord, which carry information from position sensors in the joints and muscles, can also impair balance. This damage may result from spinal tumours, circulatory disorders, nerve degeneration due to deficiency of vitamin B, or, rarely, tabes dorsalis (a complication of syphilis). A tumour or stroke that affects the cerebellum may cause clumsiness of the arms and legs and other features of impaired muscular coordination.


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