Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
Termination of growth by symmetry of positional information. Symmetrical digit bases are generated when the more proximal limb circumference breaks up into multiple separate digit bases, which are self‐terminating (left diagram). Amputation at the digit bases leads to abnormal digit patterns during regeneration (right image). Roman numerals identify each digit from anterior (I) to posterior (V). Modified from Stock and Bryant (1981).
