Anatomical Variations in Bilateral Hand Oligodactyly: A Case Analysis of Cleft Hand.

Background: Hand oligodactyly is a rare congenital malformation characterized by fewer than five digits. Although several clinical and radiological studies have been reported, detailed anatomical investigations remain scarce. This study aimed to describe the morphological characteristics of bilateral hand oligodactyly through dissection. Case Presentation: A bilateral hand oligodactyly with thumb and 3 fingers on each hand was found in a 77-year-old Korean female donor. The study was approved by the Institutional Review Board of Sungkyunkwan University (IRB No. SKKU 2023-02-012). Results: Diverse variations were observed in most structures of the hand, including the palmar aponeurosis, tendons of the flexor digitorum superficialis, the flexor digitorum profundus, and the flexor pollicis longus, lumbricals, interossei, and metacarpals. Connections between flexor and extensor tendons were also found, and each variation differed between the two hands. Conclusions: These structural differences highlight the developmental complexity of hand oligodactyly and offer valuable insights for facilitating appropriate surgical strategies. This study has also provided new insights into congenital anomalies that underscore their relevance in developmental biology.