snout reflex

[snout]
n.
  1. A pouting or pursing of the lips that is caused by light tapping of the closed lips near the midline, seen in defective pyramidal innervation of facial musculature.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.