What is the recommended injection technique for the depressor anguli oris muscle when treating marionette lines?

The recommended injection technique for the depressor anguli oris muscle involves positioning the patient at a 60-degree reclined angle, identifying the marionette line safety zone, and palpating the muscle while contracted. The injection point is at the intersection of the lateral canthal line and the nasolabial fold line, with the needle angled towards the corner of the mouth. Inject 2.5 units of botulinum toxin intramuscularly, at least 1 cm inferior to the corner of the lip, and repeat on the other side.

The injection technique for treating marionette lines with botulinum toxin involves several key steps. First, the patient should be positioned at a 60-degree reclined angle. The marionette line safety zone is identified, which is at least 1 cm anterior to the masseter muscle border and within 2 cm of the mandibular margin. The depressor anguli oris muscle is located by instructing the patient to contract it using specific facial expressions, and the muscle is palpated. The injection point is determined at the intersection of the lateral canthal line and the nasolabial fold line. Using a 30-gauge, 0.5-inch needle, 2.5 units of botulinum toxin are injected intramuscularly into the depressor anguli oris muscle, at least 1 cm below the corner of the lip, with the needle angled towards the mouth corner. This procedure is repeated for the opposite side of the face.