From Embouchure Self-Analysis, 2nd Edition by Roy Stevens. Includes detailed anatomical references of facial muscles as used in trumpet embouchure, also explained in his instructional audio tapes.
Scheme of musculature of embouchure, side view.
FIG. 1.‐M, modiolus. I, orbicularis oris (upper lip portion). 2, levator labii sup. alreque nasi. 3, levator labii
superioris. 4, levator anguli oris. 5, zygomaticus minor. 6, zygomaticus major. 7, buccinator. 8a, risorius
(masseteric strand). 8b, risorius (platysma strand). 9, depressor anguJi oris. 10, depressor labii inferioris. II,
mentalis. 12, orbicularis oris (lower lip portion).