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RESEARCH.

LEVATOR LABII SUPERIORIS.
 

                    The major use of the Levator Labii Superioris is to lift the upper lip into a sneer.  As a secondary motion it also curls up the nose and wrinkles the eye area.  The muscle has three branches.  ( see fig 12 )  All three branches come together and attach at the same spot: the circular muscle surrounding the lips, right below the wing of the nose.  When the act of sneering is commenced it is possible to feel the point where all three parts of the muscle attach, and the sharp crease that appears when they contract.  After they leave their shared attachment, the three branches separate as they travel upward to their respective bony origins.  One branch travels almost straight up alongside the nose.  The middle branch attaches to the bone of the upper jaw, just below the eye socket.  The outer branch usually referred to as the Zygomatic Minor, is fixed to the cheekbone at it's widest spot.
                    A sneer only affects the upper lip, leaving the lower just the same. ( see fig 13 )   The upper lip becomes flattened, pushed back and widened.  The lip becomes more even in width and drops straight down to it's corners, rather than tapering.  As the upper lip curls upward, it lifts slightly off the lower lip.  The lift is strongest in the outer ends, and here the gap between the lips widens.  A sneer on only one side of the lip is possible.  The other side remains relaxed.
 

Fig 12 - The Levator Labii Superioris Muscle Fibers.               Fig 13 - The Levator Labii Superioris in action.