Congenital Differences-Update on Embryology of the Upper Limb

Update on Embryology of the Upper Limb

Pdf Summary

This review discusses the embryology of the upper limb, including the steps of upper limb development and limb patterning along its three spatial axes. The embryogenesis of various congenital hand anomalies is also discussed, with an emphasis on the pathogenetic basis for each anomaly. Important steps of upper limb development include the appearance of the limb bud, division of the limb bud into four zones (stylopod, zeugopod, mesopod, and autopod), and the chondrification and ossification of the limb bones. Limb patterning is controlled by various genes and signaling molecules, such as Sonic Hedgehog (SHH), which regulates anteroposterior structural identity of the limb and plays a role in the development of specific structures, such as the ulna and hand. The review also covers the embryogenesis of several congenital hand anomalies, including Poland syndrome, persistent median artery, constriction band syndrome, amelia, syndactyly, brachydactyly, camptodactyly, and thumb duplication. The pathogenesis of these anomalies is described, including the genetic mutations that lead to their development. Overall, this review provides an overview of the embryology of the upper limb and the underlying mechanisms that contribute to the development of various congenital hand anomalies.

Keywords

embryology

upper limb

development

limb patterning

congenital hand anomalies

limb bud

chondrification

ossification

Sonic Hedgehog

pathogenesis