Botulinum Toxin Injection



I’m going to introduce our next model, Ann. When I asked her what her primary concern was, she pointed to just one area: her jawline. She told me that she hates her jowls, and she was really pointing to the area just below her mouth corners, which she feels have been getting worse over the last few years. When we look at her face, we can see that the upper and mid parts of her face are well preserved, but she is getting a bit of deterioration in that bottom third. We can see that if we were to give her a little bit of cheekbone elevation, this would improve the jawline, however it is always important to look at not only lifting from the midface, but seeing if there is any depressor activity in the lower face that might be contributing to the jowling by pulling down on the lower parts of the face. Accordingly, I will ask her to animate so that we can look at her muscle activity. If we look at what happens when she activates the mentalis and the DAO, we notice that she’s getting some puckering of the chin due to the mentalis, whilst at the same time she is also actively able to pull the mouth corners down with DAO action. She has a type of mouth frown where the DAO muscles are bringing the oral commissures down while the mentalis is elevating the central part of the lower lip. This has the effect of bringing down the soft tissue of her lower face.


Accordingly, if we want to treat Ann, not only do we need to target the midface to give her a lift, but we need to target the muscles in the lower face which are causing the distortion. We should also look at her perioral muscles, and being a young female, when she purses her lips she is causing some radial lip lines, or lip rhytids. We can see that, although they are not very prominent at the moment, they will develop over time. Accordingly, we can use some Botox to treat them now before they become deeper and harder to treat. So, for Ann, our plan will be to target her lower face muscles with Botox whilst at the same time we will use filler in the cheekbone.

Anatomy markings

Let’s review the surface anatomy of the muscles involved in treating the perioral region with botulinum toxin. I have marked off some muscles for us to analyse, and we will begin by looking at the the DAO. The depressor angularis oris brings down the corners of the mouth and originates on the border of the mandible and inserts into the modiolus just lateral to the oral commissure. You can see the shape of the muscle outlined here. What’s important to notice is that the DAO has a narrow insertion but a wide origin along the mandible. Accordingly, when we inject it, it is safer injecting in the lower pole. Just posterior to the DAO, we can see fibres of another muscle, and this is the depressor labii inferioris, which also brings down the lateral portion of the lip. In treating the DAO, the big risk is in inadvertent diffusion of toxin to the DLI or the risorius muscle, which is found laterally and proceeds towards the masseteric fascia.


When we treat muscles in combination in the lower face, it is also important to make sure we use low doses. The mentalis is a paired muscle but my preferred technique is to treat it with one injection point in the midline to avoid inadvertent diffusion. If you see the mentalis and the DAO working together, you will see the net result is to push up the centre of the lip but bring the corners down, creating a mouth frown. Accordingly, it is not uncommon for us to treat these muscles together. We look at Ann pursing her lips and this is due to contraction of the orbicularis oris, whose muscle fibres are sphincteric around the lip. Accordingly, the lines they create will be radial and straight, typically more prominent in the upper lip than the lower lip. You will notice that I have placed two marks on the upper lip on the right and another two marks on the left. They are typically placed about 2-3 mm above the vermillion border, avoiding being very close to the oral commissure or the philtral columns. It is important when injecting in these muscles to be very superficial, because we only want to target the superficial fibres.

Injection site markings and treatment

When I treat Ann’s lower face, for educational purposes I have left the markings on, however, I will sterilise the area again, and I will avoid injecting into the actual marked areas. We will begin by treating her depressor angularis oris muscle. As we discussed, the important consideration here is to avoid diffusion of the product into neighbouring muscles.


I will begin by turning Ann to her side, and I can see the injection mark, which is low down, so I insert my needle going away from the chin towards the angle of the jaw. I insert the needle very superficially and inject two units. This will help prevent diffusion to the deeper lying depressor labii inferioris. We will repeat this on the other side with exactly the same technique. I tend to inject the patient from standing on the opposite side for this muscle so that we can ensure we are pointing the needle towards the angle of the jaw rather than towards the chin. I use another 2 units in this region, and I will then move on to treat her mentalis muscle, treating Ann in the perioral region for perioral rhytids. We are targeting the superficial fibres of her orbicularis oris muscle. I am inserting very superficially and injecting very small amounts of Botox, with just 1 unit in each of the four injection sites. Sometimes, patients may find this too much and require only 0.5 units. This can be a little bit uncomfortable, and it is therefore ideal to do this treatment when the needle is new and has not been blunted by being used in other parts of the face. After treating Ann in the upper lip area, I will now treat her in her mentalis, using a single injection site, so I insert the needle in deep and inject 4 units to treat her excessive mentalis activity.

Immediate treatment outcome

At the end of the treatment, we need to assess Ann to make sure that the cheekbone filler has been symmetrical and is even on both sides. We are aware that it has already started to give us a very subtle lift in the lower face region, and we can see that when we turn her to the side that the projection attained by augmenting the cheekbone gives us a very nice, pleasing look when viewed in the oblique angle. We call this the OG curve, which is formed by an ‘S’ shaped curve from the upper brow over the prominence of the cheek. More importantly, we need to see Ann in 6 weeks, when the effects of the Botox will show what improvement we can get in her lower face.

Dermal filler treatment of cheek

We are treating Ann in the lateral cheek region to provide lift of the lower face. I have marked out the upper and lower borders of her zygomatic arch and I am using a cannula. Because I am going to be injecting over the hairline, I use a sterile drape to keep the field sterile. I  inject my cannula deep, and I am using Juvederm Voluma as my product of choice. I use the non-injecting hand to localise and guide where I will place my product and ensure we have a smooth result. Because the cheekbone is shaped like a meteor, I prefer to have more product at the tip and less as I withdraw over the arch. It is important not to over-mould the product because we will lose the definition and projection we create. I will then repeat this in exactly the same way on the other side, so I go along the periosteum of the zygoma and the target of my treatment is the SOOF, or suborbicularis oculi fat. I am pinching to ensure that I remain deep, and I am going to use the same amount of product on both sides, which is 0.5 ml of Voluma. As I mentioned, the non-injecting hand is vital to get a harmonious and equal result. As we finish the treatment and I view Ann from the side, we can see that we have created a nice projection in this region, and the light reflection that we can see shows that the projection is in exactly the right place.

Treatment outcome at 6 weeks

We welcome back Ann 6 weeks after her initial treatment to the perioral region, the chin, the depressor angularis oris, and the cheek. The idea was to improve her lower face so that it was more harmonious with her upper and mid face. We can see that when she purses the lips she has good excursion of her lips and good muscle activity, and there does not seem to be too much diminution in her lateral rhytids. We can see that again her DAO activity is still present but it is definitely diminished compared to pretreatment. Finally, when she tenses her mentalis there appears to be less activity than pretreatment. Overall, she maintains some muscle activity but we get the feeling that the lower face appears smoother and less distorted.


We can see from the side that the filler we injected into the cheekbone has given a sustained result and a better projection when view Ann in an oblique view. It will be interesting now to see what improvement we have got from baseline at the 6 week review. When we bear in mind that we have only used 1 syringe of filler and 12 units of Botox in the entirety, I’m sure you will agree that the result is nothing short of sensational. Ann now has a very harmonious balance from upper, mid, and lower face, the jawline has improved considerably, and now if she did want further improvement, we could treat her with very minimal amounts of product. This is a good example of what can be achieved when we look at the patient harmoniously rather than treating individual areas in isolation.