How to Fix a Bottom Lip That Pulls Down when I Smile or Talk?

 

The lower lip naturally pulls down when you smile.  This is the normal physiologic function of the depressor anguli oris muscles innervated by the marginal mandibular bridge of the facial nerve.  The asymmetry that you are having can be socially embarrassing because one side may be partially paralyzed and the other is not.  You can attempt Botox in the hyperactive side to see if that helps, but short of cutting the nerve (which is not recommended), there is nothing else to do.  Sylvester Stallone has the same type of unilateral marginal mandibular nerve weakness and he has done very well with his career.

As you know, our faces and our extremities are powered by two sets of opposing muscles. In the extremities certain muscles FLEX the limbs while others EXTEND them. In the face, certain muscles are LEVATORS (LIFT) structures while other muscles pull them down (DEPRESSORS).  The wonderful array of emotions are a reflection of variable tug of war pulling between the facial levators and facial depressor muscles.

This is particularly obvious in the manner with which people smile and the movement of the corners of your mouth. The corner of the mouth is powerfully pulled down by the DEPRESSOR Anguli Oris muscle but this is opposed by several levator muscles. When the levator muscles are weakened, the depressor muscle is unopposed or minimally resisted and the corner of the mouth will be pulled down in the sad position. On the other hand, if the nerve supply to the depressor muscle is opposed, the lifting muscles will be poorly opposed - the result will be a powerful lifting of the corner of the moth with a grotesque grin (Think Jack Nicholson portrayal of "The Joker" in Batman).

You should see a neurologist who can diagnose if you did suffer nerve damage at birth. The most common cause would have been a poor or prolonged application of forceps at birth (Think Sylvester Stallone's asymmetric smile). Then depending on the condition, Botox can be used in an artistic and scientific fashion by a Plastic surgeon to weaken powerful Levators and or depressors to give you a much more symmetric and attractive smile.

Good Luck.

Dr. P. Aldea