Abnormal Hands: Focus on the Thumbs

Abstract Anomalies of the hands are often difficult to precisely diagnose. Hand malformations range from subtle deformities such as isolated fifth finger clinodactyly to abnormalities of each phalange, including the thumb. There are multiple thumb abnormalities that are associated with hundreds of different disorders. Thumbs can be aplastic, hypoplastic, triphalangeal (three phalange bones instead of two), or broad or have abnormal angulation. Any of these abnormalities can occur in isolation, or they can be associated with a multitude of aneuploidies or genetic syndromes. Detection of abnormalities in any organ system warrants evaluation of the fetal hand, including the thumb, and detection of hand abnormalities, including those of the thumb, warrant detailed interrogation of all organ systems, including the skeleton.