Treatment of expression wrinkles using neuromodulators, commonly known as Botox. That is, the medical treatment of these expression wrinkles.

Definition of Expression Wrinkles

Many patients are already familiar with this term, but others are not sure what it means. Expression wrinkles are those lines that are produced by the movements of facial expression, they are not static as those produced by the descent of the tissues or the compression of the skin. These wrinkles are usually found in areas where there is facial musculature, since it is the musculature that produces facial expressions and, therefore, wrinkles.

In this case, we are going to show in this model where these expression wrinkles are located. When we make a facial movement and frown, frown lines appear between the eyebrows. By raising the eyebrows, we activate the frontalis muscle, which is located here and pulls the eyebrows upwards, producing horizontal wrinkles on the forehead. The amount and extent of these wrinkles depends on the size of the frontalis muscle; some people have a larger frontalis muscle and others a smaller one, which affects the location and extent of the wrinkles.

Thus, we have two groups of wrinkles: those caused by the contraction of the frontalis muscle, which produces horizontal wrinkles, and those caused by the corrugator muscles, which produce vertical lines between the eyebrows. There is also a third muscle, the procerus, which when contracted produces a horizontal line between the eyebrows.

In addition, there are other expression lines caused by contraction of the orbicularis oculi muscle, a large muscle that surrounds the eyes. When they contract, especially when we close our eyes or laugh, they produce the well-known “crow’s feet”. These lines can be more or less pronounced and tend to become more evident over time, especially in people with delicate skin. In some cases, they may extend to the cheek, where the contraction of the zygomaticus major and minor muscles also plays a role.

It is important to be careful when diagnosing and treating these wrinkles, as the orbicularis oculi and zygomatic muscles may contribute to their appearance and extension. We will discuss specific treatment later, but it is essential to keep these factors in mind when addressing expression wrinkles to achieve the best results.

Muscles and Types of Wrinkles

The wrinkles that appear on the sides of the base of the nasal pyramid, which occur when we laugh or frown, are also considered expression wrinkles. These wrinkles are conspicuous and contribute to facial aging. Some people wonder if other wrinkles, such as nasolabial folds, are considered expression wrinkles. However, these creases are caused by sagging of the tissues, not by facial expression. In a previous video, we explained how to interpret and treat these folds, we invite you to watch it for more information.
Considerations for Botox Application

Now, let’s talk about botulinum toxin treatment for these wrinkles. We will start with the frontal area, where it is crucial to understand the behavior of the frontalis muscle in order to obtain a proper wrinkle control effect. Frontal lines are produced by the contraction of the frontalis muscle, which is activated by raising the eyebrows. The central lines, on the other hand, are caused by the corrugator muscles, which, when puckered, also cause the eyebrows to descend. Here, there is a balance between the muscles that pull upward (frontalis muscle) and those that pull downward (corrugator and procerus muscles).

To treat frontal wrinkles, we must also consider the treatment of wrinkles between the eyebrows. If we block only the frontalis muscle, the downward pulling force will prevail, causing the eyebrows to descend, which is undesirable. Similarly, if we treat only between the eyebrows, the upward force of the frontalis muscle will prevail, giving the appearance of raised eyebrows and a surprised expression. Therefore, it is essential to balance the treatment between these two muscle groups to maintain a neutral position of the eyebrows.

As for the lateral areas, these are usually poorly muscled, but in some patients lateral wrinkling of the eyebrows may occur. It is important to consider the patient’s wishes: some patients do not want their eyebrows to be raised too high. In these cases, we apply Botox laterally, about 2 cm away from the interpupillary line, with reduced doses (one or two units). This helps to mitigate side wrinkles without raising the eyebrows too much.

In cases where the patient desires a higher brow or has a slightly drooping brow, it is crucial not to inject botulinum toxin in certain areas. Specifically, the lateral area from the interpupillary line should be avoided to allow the little muscle present to help elevate the eyebrow. This is essential to respect both the patient’s wishes and her previous anatomy.

When treating lateral wrinkles, a compromise must be reached. If the patient wishes to completely remove the lateral wrinkles, we must warn that this may cause a lowering of the brow. Therefore, it is essential to explain that we have two options: completely remove the wrinkles and risk a droopy brow, or keep some wrinkles and preserve the position of the brow. This commitment must be understood and accepted by the patient before proceeding.

In addition to the lateral region, we will review the standard patterns for the application of botulinum toxin in a new patient. We start by dividing the facial region into several parts, using the pupils as a reference to draw vertical lines. Then, we mark approximately one centimeter above each eyebrow and draw a horizontal line, thus defining the frontal safety zone for the application of the botulinum toxin.

This central area is safe to inject and minimizes the risk of complications. We also treat the frown, injecting over the corrugator muscles and the procerus muscle, identifying them by asking the patient to frown. It is important to puncture when the muscle is relaxed, not contracted, to reduce pain.

For crow’s feet, we inject approximately 1 cm from the orbital rim. In this area, we must be careful with superficial veins, although they are not always visible. When injecting, we notice a small resistance corresponding to the fascia of the orbicularis oculi muscle, and it is at this point where we should apply the toxin.

The lowermost area of the orbicularis muscle is delicate. We should not inject more than 1 cm from the equator of the eye to avoid affecting the zygomatic muscles and causing facial paralysis. In these cases, we opt for a more superficial subcutaneous injection to treat wrinkles without penetrating too deeply.

In the upper eyelid, we can also treat lateral wrinkles subcutaneously, keeping in a safe plane so as not to affect the levator muscle of the eyelid, thus avoiding complications such as eyelid drooping.

Application in less common areas
We have covered quite a bit about facial musculature and the application of botulinum toxin. Now, we could talk about the application in less common areas, such as bunny lines on the nose, which can also be treated with this technique.

However, when botulinum toxin is applied to the lateral muscles of the nose, a good attenuation of this musculature is achieved. This is a fairly safe area, but we must be careful with a small vein that is part of the irrigation and drainage of the facial vein, which is usually quite clearly visible and can be easily avoided. It is true that this area is a little more sensitive to pain.

Another type of wrinkles, which can also be treated preventively although they are not specifically indicated in the botulinum toxin package insert, are perioral wrinkles. These vertical wrinkles around the mouth are not completely eliminated by the toxin, but its application can help to attenuate them and prevent them from becoming more pronounced. In this area, however, the toxin may not be well tolerated by all patients, as it causes a partial paralysis of the musculature that may make it difficult to perform actions such as kissing, whistling or drinking normally. Therefore, it is advisable to use low doses and to warn patients about these possible side effects.

These perioral wrinkles are more common in women, as men tend to have thicker muscles and skin in this area, which protects them more from developing these wrinkles. In women, especially smokers, it is more frequent due to the repeated contraction of the orbicularis oculi muscle when smoking.

In addition, there is another region that can be treated, although it is not officially indicated: the depressor muscle of the angle of the mouth. This muscle is responsible for the drooping of the angles of the mouth. Injecting botulinum toxin in this area may help to slightly elevate the angles of the mouth. To do this, I usually use my finger, protected with a sterile glove, inside the mouth to guide the needle and prevent the liquid from being deposited in the oral cavity. I usually use two units maximum, which is usually enough to slightly relax this muscle and allow a subtle elevation of the angles of the mouth.

Another “off-label” treatable area is the platysma muscle. The action of the platysma muscle is a depressor of the facial musculature and in incipient cases of sagging, particularly jaw sagging, paralysis with a low dose of botulinum toxin of the platysma can help us to compensate for this sagging and even elevate it slightly.

It is important to manage patient expectations , as full elevation of the angles of the mouth is not achieved with botulinum toxin alone. In more severe cases, where the corners of the mouth are very low, it is necessary to combine the toxin with other treatments such as fillers for perioral wrinkles or even a surgical elevation procedure of the corner of the mouth. This procedure, performed under local anesthesia, repositions the angle of the mouth to improve both esthetics and functionality, preventing problems such as saliva drooling that can lead to infections in the folds.

I hope this information has been useful. If you have any doubts or questions, please leave your comments or contact us. Best regards!