Science, Art, Litt, Science based Art & Science Communication
Heard about it? Or its scientific name?
Mirror hand or ulnar dimelia is a rare congenital anomaly of the upper limb. Typically there are seven digits which are symmetrical along a sagittal axis with two ulnae and absent radius. The etiology of mirror hand has been attributed to the replication of zone of polarizing activity (ZPA) signaling center located in the posterior margin of the limb bud that controls the radio ulnar development through the signaling molecule, sonic hedgehog protein. Different anatomical presentation of mirror hand is seen with mirror hand. Researchers have proposed a classification of mirror hand deformity based on the presence or absence of other congenital anomalies and the type of fore arm bone
Ulnar dimelia, referred to simply as mirror hand, is a very rare congenital disorder characterized by the absence of the radial ray, duplication of the ulna, duplication of the carpal, metacarpal, and phalanx bones, and symmetric polydactyly. In some cases surgical amputation is performed to remove the duplicate carpals, metacarpals and phalanges. As of 2015, approximately 70 cases have been recorded in the medical literature.
Bone deformity may also accompany nervous and arterial anomalies in some cases due to the duplication of the ulnar nerve, the presence of abnormal arterial arches, the duplication of the ulnar artery, the shortening of the radial nerve, and the absence of the radial artery. The diagnosis of ulnar dimelia is based on laboratory tests of frontal and sagittal planes in individuals suspected of the condition. There are two types of ulnar dimelia noted in medical journals: Type 1 ulnar dimelia entails one lunate and one trapezoid bone as well as one index finger, while type 2 ulnar dimelia has two lunate and two trapezoid bones as well as two index fingers.