Challenge of the Week / Hand & Wrist / 06.19.20

A defect in the apical ectodermal ridge (AER) will lead to which of the following types of congenital limb difference?
  • Transverse deficiency
  • The AER regulates proximal-to-distal limb development. Therefore, a defect in the AER results in a transverse deficiency.

  • Syndactyly
  • Syndactyly occurs as a result of failure of apoptosis in the developing web space.

  • Constriction band syndrome
  • Constriction band syndrome results from an amniotic band wrapping around an appendage in utero. This is a deformation rather than a malformation.

  • Mirror Hand
  • Mirror hand occurs as a result of a duplicated zone of polarizing activity (ZPA) such that both sides of the hand are ulnarized.

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.