Question

What is the positioning of the facial muscles in relation to the instrument and the performer’s physical characteristics called

Answer 1

embouchure hope this helps

Answer 2

It is called Embouchure or lipping.

Step-by-step explanation:

It´s most commonly used for wind instruments whether they are made of wood or brass. The word is of French origin and is related to the root "bouche" which means mouth. Proper embouchure allows musicians to play their instruments at its full range without harming their muscles.

I hope this answer helps you.