Understanding the Anatomy Behind Forehead Wrinkles

These wrinkles are produced by contraction of the paired frontalis muscles.

Contraction of the paired frontalis muscles raises the eyebrows and upper eyelid skin, producing transverse creases in the forehead.

Origin: galea aponeurotica of the cranium

Insertion: skin of the eyebrows

Although the frontalis muscles are often described as paired muscles that do not meet centrally, the central forehead is not devoid of wrinkles.

Treatment should therefore include injections in the central aspect of the forehead.

The upper face must be assessed both in animation and at rest prior to injection.

Location Of Brow:

• In women, the brow should lie at or just above the superior orbital rim.
• In men, it should lie at the bony rim.

How To Inject

1. Have the patient raise and lower the brow to assess the extent of muscle movement.
2. Frontalis muscles are located superficially, injections should be placed in the superficial subcutaneous tissue.
3. Treat the entire forehead from medial to lateral. Male patients may require a higher dose.
4. The typical dose ranges from 10 to 20 BU or 30 to 60 DU.

Stay Safe

Injecting the forehead with neurotoxins can be challenging, and careful planning is essential to avoid common errors like overtreatment or poor injection placement. Here are some key precautions:

• Assess Brow Position:

1. Always evaluate the position of the brows at rest before injecting.
2. Determine if there is brow ptosis or increased resting tone of the muscles, which can mask brow ptosis.

• Compensation for Brow Ptosis:

Horizontal forehead creases can be a result of compensation for brow ptosis.

1. If the brow is already ptotic, avoid injecting the frontalis muscles as this will worsen the condition.
2. If you must inject a patient with brow ptosis, plan injections high in the forehead to retain some brow elevation movement or consider undertreating this area.

• Relax the Frontalis Muscles:

Sometimes the frontalis muscles show a resting tonic contraction that must be relaxed to accurately determine the brow's resting position.

1. You might need to manually smooth out the forehead to encourage relaxation.
2. Having the patient close their eyes can also help relax the frontalis muscles.
3. Once relaxed, reassess the brow position to check if the contraction was masking brow ptosis.

• Avoid Odd-Shaped Brows:

Poor technique can result in an odd-shaped brow.

Do not limit injections to the central brow, and do not assume that injections cannot extend laterally.

• Treating only the center of the brow can cause the brow to drop medially and elevate laterally, creating an unnatural, slanted look known as the “Mr. Spock” or “Mephisto” sign.
• While a lateral brow lift can be achieved using this technique, proceed with caution to avoid an overly slanted medial brow.

Post-Injection Instructions

instruct the patient to avoid exercising immediately. Bruising can decrease the effectiveness of BoNTA by preventing its diffusion to the neuromuscular junction.

Risks

• Major Risks:
• Ptosis of the upper eyelid
• Unmasking of brow ptosis
• Minor Risks:
• Inappropriate injection planning, leading to unnatural-appearing brows or persistent wrinkles

Practical Tips For Injection

1. Watch Muscle Movements: Make sure to observe the patient’s forehead muscles as they contract and relax to plan where to inject.
2. Cover the Entire Area: If the wrinkles go up to the hairline, inject all the way to avoid leaving a ridge of wrinkles above a smooth forehead.
3. Check the Sides of the Brow: Sometimes, the sides of the brow are missed, leading to deep creases above the lateral brow.
4. Assess for Ptosis: If a patient has a drooping upper eyelid, be careful. Injecting the forehead could make the drooping worse. Examine these areas closely before injecting.
5. Combined Doses: In some cases, one dose of BoNTA can treat both the glabella and the forehead.