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Mirror brush, or ulnar dimelia: causes, symptoms, diagnosis, treatment
Last reviewed: 04.07.2025

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"Mirror hand", or ulnar dimelia is a rare congenital anomaly characterized by doubling of the ulna, absence of the radius and the first finger of the hand, excessive number of fingers, usually symmetrically located relative to the midline. Usually, limited movement in the elbow joint, rotational movements of the hand are visualized, since in these patients, instead of the head of the radius, the proximal part of the second ulna is involved in the elbow joint. In addition to the classic form of "mirror hand", intermediate variants of this anomaly are also possible: radial polydactyly (doubling of the first finger and its triphalangism) is combined with a normally developed forearm, with three bones of the forearm, syndactyly of the fingers of the hand.
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Diagnosis and treatment of "mirror hand" or ulnar dimelia
Diagnosis is straightforward. Characteristic features include a large number of fingers (usually 7 or 8) and a widened hand.
Treatment is surgical only. The optimal age for treatment is over 1 year. The operations are complex and must be performed only in specialized hand surgery centers. Surgical interventions are aimed at eliminating the deformation of the hand, wrist and elbow joint. Pollicization surgery is performed on the hand (reconstruction of the first finger from one three-phalangeal finger) with simultaneous removal of additional rays, which allows restoring a five-fingered hand with good bilateral grip function, as well as improving its cosmetic appearance.
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