A developmental defect characterized by reduced length of the first metacarpal (long bone) of the hand.
Comment:
In contrast to the proximal phalanges of the digits 2-5, the proximal phalanx of the thumb is embryologically equivalent to the middle phalanges of the other digits, whereas the first metacarpal is embryologically of phalangeal origin and as such equivalent to the proximal phalanges of the other digits. {xref="https://orcid.org/0000-0002-0736-9199"}
Synonyms:
exact_synonym:
First metacarpal hypoplasia; First metacarpals hypoplastic; Hypoplastic 1st metacarpal; Short first metacarpal; Short first metacarpals; Shortened 1st long bone of hand