The Dance of the Lower Face: A Masterclass in Advanced Botox
There is a secret territory in aesthetic medicine that separates the novice from the true artist. It is not the forehead, nor the crow's feet. It is the lower face—a complex, living landscape of muscles that pull in opposing directions, each creating a subtle expression that defines a person's character. To journey here without deep understanding is to risk the very thing your patient values most: their smile.
Let us start with the elevators, the muscles that lift. There are four key players you must know intimately: the levator labii superioris alaeque nasi, the levator labii superioris, the levator anguli oris, and the zygomatic minor. These muscles are not merely for smiling. They weave into expressions of disgust, of a full laugh, and most famously, of a gummy smile. When you aim to moderate that quick flash of gum tissue, whether with toxin or with dermal fillers, these are the muscles you seek to dampen, to soften their strength.
But here lies the peril. Overtreat or treat asymmetrically, and you invite a side effect that is devastatingly obvious: an asymmetrical smile. This is not subtle. A patient's smile is a signature of their soul, and any flaw in it is immediately visible to their friends and family. This often happens inadvertently. For example, when injecting the orbicularis oculi for crow's feet, a needle that goes too deep, passing through the fat pad, can strike the origin of the zygomatic major. The result? A smile that pulls unevenly, a haunting reminder of a technical error.
Even the well-intentioned gummy smile treatment carries risk. You might achieve a brilliant before-and-after photo—a technically perfect result—yet the patient themselves may dislike it. Why? Because suppressing the elevators changes the dynamic nature of a smile. To those who know their face intimately, the new smile can feel insincere, a little odd. It takes getting used to. In your consultation, you must prepare them for this possibility. Sometimes, the benefit is not worth the adjustment, and you may instead suggest a different method, such as a dermal filler.
Other treatments also threaten the smile. When treating the masseter, if you inject slightly too superior and too medial, you can affect the risorius muscle. This causes an even more upsetting asymmetry—the corner of the mouth is pulled in a strange way during a big smile. The common injection pattern for masseter reduction, as often taught online, draws a line that ends dangerously close to the oral commissure. Half a centimeter or a centimeter differently, and you are right in the risorius. I have seen this mistake many times in training. My own approach is to use a different boundary: the mental crease. Treat only the lower third of the masseter, with the mental crease as your inferior limit. This simple shift moves you away from the risorius insertion, dramatically reducing the risk.
But even with the right boundary, depth matters. The risorius is relatively superficial, inserting into the fascia around the masseter. By injecting deep into the masseter, you avoid the superficial fibers. Two safeguards: inferior to the problem area, and deep enough to miss it.
From Elevators to Depressors: The Pull Down
Now we descend to the muscles that pull the mouth down. The first is the depressor anguli oris (DAO). This muscle pulls the corner of the mouth downward and laterally. You can treat it deliberately to slightly weaken its pull, allowing the corners of the mouth to elevate naturally—a subtle lift without filler. But how do you decide when to use toxin versus filler? Look for a hypertonic component. If during expression you see a strong downward pull, like a certain famous actor with a permanent frown, then there is a muscular element you can relax. Another depressor, the depressor labii inferioris, pulls the lower lip directly downward, as seen in certain public figures. Observe faces in motion. Your aim is harmony.
Relaxing these depressors can treat a "sad face," especially in older patients or those with hypertonic contractions from Bell's palsy. But proceed with caution. Relax the DAO too much, and you get a joker smile—the corners lifted grotesquely high. Relax it asymmetrically, and expression becomes lopsided. Worse, if you inadvertently affect the depressor labii instead of the DAO, the lower lip itself becomes asymmetrical when smiling. Many things can go wrong, but most treatments succeed—that is why we continue. Yet it is complex, which is why this is advanced work.
The injection technique for the DAO is debated. One common method is to inject along the angle of the jaw, aiming for the insertion. But underneath that point lies the depressor labii—the two muscles overlap near their insertion, so you risk affecting the wrong muscle. I prefer to move up, to a point roughly halfway between the oral commissure and the jawline. Ask your patient to contract the muscle. You can actually feel the boundary of the DAO with your finger. Behind it lies mostly buccinator and risorius, so with a small, precise dose, you can isolate your target.
The Platysma Bands: A Superficial Connection
Finally, consider the platysma. This is a thin, sheet-like muscle that collects into bands in the neck. It is connected to the SMAS (superficial musculoaponeurotic system). By relaxing these bands—often in a treatment called the Nefertiti lift—you can create a beautiful definition of the jawline in a percentage of patients. But again, the anatomy is messy. In many people, the platysma bands are woven into the depressors, particularly the DAO. If you inject very high up, you can cause asymmetry in the lower mouth when the patient smiles. The textbook never shows these variations. You must be prepared.
The Art of Consultation and Precision
What are the general principles for all these treatments? First, consultation is paramount. Prepare your patients for subtleties. This is not a simple "inject and be happy" situation. There may be an adjustment period, a period of learning to feel comfortable with a changed smile. Second, be precise with your doses. Do not rely solely on memory for muscle location. Feel the muscles with your fingers. The human body is not a diagram. Start with small amounts on your first pass. You can always add more later. Once you understand that particular patient's anatomy and response, you can work up to textbook doses. If you go too heavy on these subtle treatments, you will lose patients. And our reason for being is to make them happy.
Think of lower face toxin as a journey. Small doses. Careful palpation. And always, always respect the delicate dance of muscles that makes a smile genuine.