The pout reflex consists of a pouting movement of the lips elicited by lightly tapping orbicularis oris with a finger or tendon hammer, or by tapping a spatula placed over the lips. This myotactic stretch reflex is indicative of a bilateral upper motor neurone lesion, which may be due to cerebrovascular small vessel disease, motor neurone disease or multiple sclerosis. It differs from the snout reflex, which refers to the reflex elicited by constant pressure on the philtrum.
Rossor M. Snouting, pouting and rooting. Practical Neurology 2001;