Precise Injection Sites for OnabotulinumtoxinA (Botox) in the Lower Face
The FDA-approved injection sites for onabotulinumtoxinA in the lower face include specific locations for platysma bands, with injections administered 1-2 cm inferior to the lower mandibular border for jawline injections and vertically along identified neck bands. 1
Platysma Bands Injection Technique
Jawline Injections
- Inject 2 Units (0.05 mL) into 4 sites in the upper platysma muscle on each side:
- Position: 1-2 cm inferior and parallel to the lower mandibular border
- Anterior site: Align with the oral commissure
- Posterior site: Slightly anterior to the angle of the mandible
- Middle sites: Place 2 injections equidistant between anterior and posterior points (approximately 1-2 cm apart)
Vertical Neck Band Injections
- Inject 1 Unit (0.025 mL) into 5 sites along each identified vertical neck band:
- Distribute 5 injections vertically at approximately 1-2 cm intervals
- Ensure the most superior injection site is approximately 1-2 cm inferior to the jawline injections
- Total dose varies based on band severity:
- 26 Units (1 band/side)
- 31 Units (1 band one side, 2 bands other side)
- 36 Units (2 bands/side)
Administration Technique
- Use superficial intramuscular injections with the needle perpendicular to the skin surface
- For vertical neck bands, identify each band during platysma contraction
- Gently pinch the band to isolate the muscle from nearby structures
- Critical safety point: Administer injections at least 1 cm inferior to the lower mandibular border
- Do not inject into structures deep to the platysma muscle, particularly in the anterior neck region 1
Mentalis Muscle Injection (For Chin Dimpling)
Based on anatomical studies, the mentalis muscle is typically located:
- 5-10 mm from the midsagittal line
- 20-30 mm from a horizontal line connecting the mouth corners
- At a depth of 6.7-10.7 mm below the skin surface 2
The mentalis muscle typically presents in one of two forms:
- Type A (86.4%): Dome-shaped in three dimensions
- Type B (13.6%): Flat 2
Important Safety Considerations
Anatomical Precautions
- The lower face has complex musculature with muscles in close proximity that interface at different levels and depths
- These muscles perform critical functions including talking, eating, and drinking
- Injection errors in the perioral area can lead to significant functional complications 3
Technique Recommendations
- Start with lower doses and more frequent touch-ups when first injecting the lower face
- Avoid large initial doses to prevent severe complications 4
- Topical anesthesia may be used to enhance patient comfort during injections 5
Contraindications
- Known hypersensitivity to botulinum toxin preparations or components
- Presence of infection at proposed injection sites 1
Post-Procedure Care
- Remain upright for 3-4 hours after treatment
- Avoid touching or massaging treated areas
- Refrain from strenuous exercise for 24 hours
- Avoid alcohol consumption for 24 hours
- Monitor for potential toxin spread within the first 24-48 hours after injection 6
The use of botulinum toxin in the lower face requires precise anatomical knowledge and technical expertise due to the complexity of the musculature and the higher risk of adverse events compared to upper face applications. For optimal results with minimal complications, practitioners should follow these specific injection guidelines while considering individual facial anatomy.