has part has part characteristic of part of inheres in part of has modifier Abnormality of thumb phalanx Abnormality of the proximal phalanx of the thumb 2009-01-29T04:13:47Z HP:0009618 HP:0004076 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. Abnormality of proximal thumb phalanx UMLS:C4021421 An anomaly of the shape or form of the proximal phalanx of the thumb. Abnormal innermost thumb bone abnormal proximal to manual digit 1 phalanx