Dictionary.com
definitions

Musset's sign

[mōō-sāz′, mü-]
n.
  1. An indication of aortic insufficiency in which the head rhythmically nods in synchrony with the heartbeat.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.