Botulinum Toxin Injection


General assessment

I would like to introduce our next patient, Hanna, who is currently 30 years old. When I asked her what she would ideally be looking to improve, she mentioned that she had 3 primary concerns. Her first concern was her chin – she described this as a ‘witch’s chin,’ by which she meant that she had a little bit of excessive anterior projection, and she felt that the chin was dominant. Her next indication was the under eye hollows, and finally, she was seeking to improve the size and shape of her lips.


Let’s have a look at her face shape – when we look at her from the front, we can see that she is young and attractive, and in line with that, she has a very nice dominant cheekbone that we can see leading down. However, she also has a very dominant jaw, which gives off a little bit of a square shape to the face. We do know that the ideal face shape for a female is a heart, formed by the cheekbones coming down into a delicate chin, or an oval, but in Hanna’s case, the angle of the jaw gives a bit of squaring. We can see that if we were able to contour the jawline, we would potentially make her more attractive and give her a more delicate face shape.

Upper third assessment

Now let’s examine her in detail, and we will begin by analysing her upper third, from the trichion to the glabella, we will notice that, as she is young, she clearly has a good convexity of her forehead, both in the vertical and the horizontal region, especially in the middle. However, look above her eyebrow, and we will notice that she is just a little bit hollow on both sides. The second thing that we will notice is that she has some visible static lines in her forehead, and we can see that if I ask her to raise her eyebrows, we will notice that those lines do become deeper, especially in the central region, so she is already a good candidate for treatment with Botox.


I would now like to look at the shape of her brow, and we can see that the brow is in the shape of an upside down ‘v’ and we can also see the apex of her brow is about halfway along. Ideally, we would want the apex at about two thirds along the brow, and we see that if we were to get this shape, it would allow for a more open eye and a more attractive brow, so ideally we want to shift the apex from the lateral limbus to the lateral canthus, and overall this would give the gull’s wing appearance of a brow that is deemed to be the most attractive. Let’s now analyse Hannah’s frown, and if I ask her to frown, you will notice it is powerful, and she recruits very laterally on both sides. You will also notice her right appears to be more dominant and we can see clearly the outlines of the heads of corrugator during animation. When she frowns a little bit deeper, we can also see a number of lines on the upper part of the nose, and these are caused by the contraction of the procerus muscle.


The final point of contention about her upper third is that, if I look at the region just below the brow, you will notice that she appears to have a deep sulcus in the upper orbital region. While this may not bother her now, this may be a target for rejuvenation at some point in the future.

Muscle anatomy markings

In this video, let’s have a look at the surface anatomy of some of the upper face muscles that we target with botulinum toxin during our treatments. If we look at Hannah now, you will notice the two lines at the side of her face which denote the temporal crests, and in the vast majority of people, the frontalis lies between these crests. The frontalis originates from the galea aperneurotica, and then will insert into fibres of the procerus, corrugator, and orbicularis oculi. In the midline, the fibres of the frontalis may be absent and replaced by the galea. The frontalis is the only elevator in the brow, and we can see Hannah here as she raises the brow, she forms horizontal creases. On the right, I have denoted the corrugator muscle in purple, and on the left, I have denoted the orbicularis oculi. Remember, the lower fibres of the frontalis will interdigitate with the corrugator, procerus, and orbicularis oculi, and therefore we have to be very careful with toxin placement and depth in this region.


Now let’s have a look at the brow depressor complex. The first muscle to look at here is the procerus which originates from the fascia overlying the lower nasal bones and cartilage and inserts into the skin between the eyebrows and also the lower fibres of the frontalis. Its action is to bring the heads of the brow inferiorly down, and in doing so it creates transverse lines on the bridge of the nose. The next muscle to look at is the corrugator supercilii, which has an origin on the superciliary arch of the orbital rim, and the fibres then ascend vertically, laterally, and anteriorly to insert into the dermis of the skin. The insertion will have a variable place, and may be medial to the mid-pupillary line or lateral. If I get Hannah to frown, we notice that there is a little dimple at the insertion of the corrugator. The important message here is that when we inject the head of the corrugator, we must be deep onto bone where the origin is, however, when we inject the tail, it is important to be superficial as the insertion is in the skin. If we are deep, we can actually cause lid ptosis due to the toxin affecting the levator palpebrae muscle.


Finally, we have the orbicularis oculi, which has an orbital portion, a pretarsal, and a preseptal portion. The pretarsal and preseptal portions are involved in the involuntary blink reflex, and the orbital portion is involved in voluntary eye closure. If I get Hannah to scrunch her eyes shut tightly, we will notice a couple of things – we can see that from the side view, the first thing is that she may form some lateral canthal lines, or crow’s feet. The vertical portion of the orbicularis oculi causes the tail of the brow to descend. Accordingly, we can take advantage of this and inject toxin into the tail of the brow, which can give us a lateral brow elevation due to action of some fibres of the frontalis.

Injection site markings and treatment

For the procerus injection point, take a line from one medial canthus to the opposite head of brow and repeat on the other side. Where these two diagonal lines intersect will be our first injection point. For the head of corrugator make a line coming up from the medial canthus and palpate the muscle just above the orbital rim and, in line with the medial canthus, we place a second dot. We can then repeat this on the other side. These are our first three injection markings.


Next, we need to mark out the points for the tail of the corrugator. When I ask Hannah to frown, I will then palpate the orbital rim and go a centimetre above the rim just medial to the mid-pupillary line. You will notice that these dots form a ‘v’ shape. I now want to mark out the injection points for the frontalis, when I get her to elevate the brows I can see the extent of the lines and I will then proceed to make the injection marks across the forehead. I keep the marks in the centre of the forehead slightly lower, but the lateral marks higher because I want to give her the maximum brow elevation. Finally, I palpate the lateral temporal fusion lines. In this region, the orbicularis oculi muscle fibres go from horizontal to vertical, and the action is to pull the tail of the brow down. Accordingly, if we inject with botulinum toxin, we can get a subtle elevation of the brow.


Let’s begin with injecting the procerus, you will notice I pinch the skin between my finger and thumb and insert my needle the full length, because this is a deep injection, and then I gently inject the first 4 units into the muscle. Next, I move on to the head of the corrugator on her left side. I use a finger in the orbital rim to prevent diffusion, pinching up and squeezing the muscle, again using a deep injection with the full length of the needle down, injecting another 4 units. I will now move on to her right head of corrugator, this time using my thumb in the orbital rim, with deep placement of the full length of the needle, using another 4 units. When I inject the tail of the corrugator, I have to use a different approach. Because I want to be as superficial as possible, I will come in from the side and angle my needle so I am just intradermal just put the beginning of the needle in, before injecting 2 units. Ideally, I want to raise an intradermal bleb, and I want to repeat this on the other side, with another 2 units injected superficially.


When I inject the frontalis, my preferred depth of injection is intradermal. Some injectors go deeper, almost onto the bone, however I think that patients find this more painful. Accordingly, I keep my needle and syringe relatively flat, and then inject just with the tip of the needle into dermis of the skin, knowing that the toxin here will diffuse into the muscle. The dose that I am using for Hannah here is 1.5 units in each of the injection sites. This might be a slight undertreatment, but I can always add a bit more at review. If we inject too much product here, it can lead to brow ptosis.


Finally, we inject the orbicularis at the tail of the brow for our brow lift, and the most important thing here is the depth – we need to be as superficial as possible because the very thin muscle is just below the skin. Accordingly, I just introduce the tip of my needle and inject 2 units at the tail of the brow.

Treatment outcome at 6 weeks

We have our patient Hanna here, at 6 weeks following some botulinum toxin treatment and some dermal filler treatment. The first thing to notice is a significantly improved facial shape – we can see, due to the masseter Botox treatment, that she now has a more feminine, oval, or heart-shaped face. This is due to a diminution in the projection and angle of the jaw when we treated the masseter. We can see that when she frowns, she has practically no activity of the procerus or corrugator, and that when she raises her brow, there is some movement, but lines are diminished. This is the perfect ideal for frontalis treatment because we have preserved movement while reducing the lines.


If you look at her brow shape, you will also notice that the tails of the brow have lifted, and are more aesthetically pleasing. When we look at the chin, we notice that it is now soft and there is no longer the cobblestone appearance that she had pre-treatment. If we turn Hanna to the side, we will notice that the chin is still slightly projected anteriorly, but considerably less so than previously. If we turn her to the side and get her to smile, we will notice that the little lines she had in her cheek have also reduced substantially following the treatment to her masseter. Also notice the significant improvement of the under eye area after treatment.