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.
Image of triphalangeal thumb of the right and left hand of the mother (.1) and her newborn (.2) reported by Heiss (1953) and reproduced from Zeitschrift fur Anatomie und Entwicklungsgeschicte with permission of Springer Nature (licence no. 4334811065195).
