1. Lack of equality between opposing forces. 2. Lack of equality in some aspect of binocular vision, such as muscle balance, image size, and/or image shape. [L. in- neg. + bi-lanx (-lanc-), having two scales, fr. bis, twice, + lanx, dish, scale of a balance]
- autonomic i. a lack of balance between sympathetic and parasympathetic nervous systems, especially in relation to the vasomotor disturbances. SYN: vasomotor i..
- occlusal i. an inharmonious relationship between the teeth of the maxilla and mandible during closing or functional movements of the jaw.
- sex chromosome i. any abnormal pattern of sex chromosomes; e.g., XXY in men with seminiferous tubule dysgenesis, XO in women with Turner syndrome; rarer patterns of i. are XXX, XXXY, and XYY. SEE ALSO: isochromosome.
- vasomotor i. SYN: autonomic i..

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im·bal·ance (')im-'bal-ən(t)s n lack of balance: the state of being out of equilibrium or out of proportion: as
a) loss of parallel relation between the optical axes of the eyes caused by faulty action of the extrinsic muscles and often resulting in diplopia
b) absence of biological equilibrium <a vitamin \imbalance> <if the ductus arteriosus fails to close, a circulatory \imbalance results (E. B. Steen & Ashley Montagu)>
c) a disproportion between the number of males and females in a population
im·bal·anced -ən(t)st adj

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im·bal·ance (im-balґəns) 1. dysequilibrium (def. 2). 2. inability to stand upright; lack of balance between muscles.

Medical dictionary. 2011.