July 20, 2023

Facial Muscles Anatomy

If you want to increase your confidence when delivering botulinum toxin injections in facial aesthetics, it starts by upping your anatomy knowledge; more specifically, your understanding of the muscular anatomy of the face.

In this blog, Dr Tim Pearce will start at the top of the face and works his way down explaining each of the muscles and their function within the upper, mid, and lower face, alongside how we can treat these muscles for aesthetic improvement.

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Muscles in the upper face


The frontalis is also called the occipitofrontalis because it often has a connection that runs all the way from the occipital bone through to the brow ridge. This muscle is involved in elevating the eyebrows and there is often a component that pulls the forehead down towards it as well. We treat frontalis with botulinum toxin to reduce and remove horizontal forehead lines and to lift the eyebrows.


The procerus muscle is part of the corrugator or glabellar complex. This muscle is a depressor. It pulls the forehead downwards and creates a horizontal line on the top of the nose which is the most common reason you might treat it in isolation to rid the patient of the distinctive wrinkle. Treatment is sometimes used as part of a non-surgical rhinoplasty.

Corrugator supercilii

The corrugator supercilii is the muscle predominantly responsible for creating the so-called eleven lines. This muscle starts on the bone, just above the nose, and runs to the dermis of the skin on each side of the face, along the eyebrows. When used to frown, the corrugator supercilii pull the skin inwards causing the two crease lines in the midline. We can treat this muscle with botulinum toxin to reduce its activity to remove the angry expression and restore a more relaxed and softer appearance.

Depressor supercilii

The depressor supercilii muscles cross the corrugators. Often considered to be a small branch of orbicularis oculi, they do contribute to frowning. The depressor supercilii is usually treated alongside the glabellar complex without directly thinking about it because it is integrated with the corrugator supercilii and thus injected as part of a frown line treatment. It can be addressed in isolation as a way of causing a small lift to the medial brow.

Orbicularis oculi

brow muscles anatomyThe orbicularis oculi muscle is the most superficial muscle in this area. It lies on top of the others and is most involved with causing lateral canthal lines or crow’s feet at the corners of the eyes. It is responsible for the narrowing of the eyes – if you close your eyes tightly, orbicularis oculi is doing the work – it pulls the eyebrows down, pulls the cheeks up, and creates wrinkles around your eyes. You can relax this muscle with botulinum toxin to achieve the opposite effects – perhaps a little lift to the eyebrow or to reduce the lateral canthal lines, and, as an undesirable side effect, it is worth understanding that relaxing it can make the cheek less elevated during smiling. Find further reading with Treating Orbicularis Oculi with Botox: What can go wrong?

Muscles in the mid face

Zygomaticus major

The zygomaticus major muscle is the primary muscle involved in smiling, in elevating the corners of the mouth, and pulling the cheeks up. It is therefore very rare to inject it for cosmetic reasons, normally the aim is to try and avoid impacting it because we want the smile to be active.

Zygomaticus minor

Medial to the zygomaticus major is the zygomaticus minor, a lip elevator that similarly we want to preserve.

Levator labii superioris

Medial and inferior to the zygomaticus minor is the levator labii superioris. This is also a lip elevator which we do not purposely inject with botulinum toxin, but it can be targeted as part of treatment to address a gummy smile.

Levator labii superioris alaeque nasi

Continuing medially, we find the longest named muscle in the body, the levator labii superioris alaeque nasi. This muscle is also involved with directly elevating the lip and creating the snarl expression by pulling on the nostril. When treated, it is usually to stop its elevation and impede the gums from showing during a smile with an injection of botulinum toxin placed lateral to the nostril.

Orbicularis oris

Within the middle of the face, we find the orbicularis oris muscle. This is embryologically four muscles that come together and form what looks to the untrained eye like a sphincter type muscle but is not. The orbicularis oris is involved in contracting the upper and the lower lip to narrow the mouth to facilitate speech, expression, and actions like whistling.

It can be injected with botulinum toxin to reduce some of the superficial muscle fibre strength if a patient has upper or lower lip lines, and increasingly, doses are being used to add some degree of augmentation to the lip with the so-called Lip Flip procedure. One of the theories behind the Lip Flip is that you are relaxing the muscle where it inserts into the vermilion border. This makes that part of the lip bigger, with a slight increase in resting tone in the muscle that is superior, effectively mimicking a pout – contracting higher up and relaxing lower down to achieve a very subtle pout effect than can work in some patients.

Muscles in the lower face

Depressor anguli oris

Moving lower in the face, we encounter the depressors, starting laterally with the depressor anguli oris (DAO). This muscle pulls down the corner of the mouth, therefore, ageing and the loss of fat and resistance to movement can result in a downturned mouth. If you relax the DAO with a few units of Botox® on each side, the opposite can occur, and you will achieve a small lift to the corners of the mouth.

Depressor labii

Medial and deep to the depressor anguli oris is the depressor labii muscle which is involved in pulling the lip outwards. This muscle can be quite strong in some people, leading to a strong lateral pull that shows all their lower teeth when smiling.


Medial to the depressor labii is the mentalis muscle which pulls the chin upwards. It starts on the bone, in the middle of the chin, and the fibres go down and meet at the point of the chin. You can often see the muscle fibres as they cause small indentations on the chin on contraction creating an orange peel appearance as they pull the skin inwards. This effect is one of the reasons for treatment, placing up to four to six units of Botox in the muscle to reduce the texturing on the chin. It can also help to maintain the chin at the low point of the face, conducive with the beauty of a heart-shaped face.


The buccinator is a muscle that runs on the deepest surface of the cheek and above it is a fat pad. It is never treated with botulinum toxin but one which you should be aware of so you can avoid it. There are two interesting facts about the buccinator. Firstly, it is the strongest muscle in a baby’s body because it is used for sucking during breastfeeding or from a bottle, and secondly, it is also used by bugle players to play the instrument!


On the other side of the fat pad, and above the buccinator muscle, is the risorius muscle. Its origin is the surface of the masseter muscle, and it contributes to smiling. We see this muscle most active on the face during a hearty laugh when all the muscles are contracting and pulling sideways. The main reason this muscle is discussed in medical aesthetics is as a side effect or complication from treating the masseter muscle with botulinum toxin. You can accidentally relax the risorius muscle whilst attempting a jawline slimming procedure by hitting its origin, consequently affecting, or reducing the smile.


The masseter muscle runs from the zygomas and is involved in biting. It is the strongest muscle during contraction and can be felt and seen clearly when asking the patient to clench their teeth. This is a useful test when evaluating jawline slimming procedures. You will clearly see how much is pushed out laterally, which can adversely affect the facial shape, particularly in females who seek facial narrowing and a heart-shaped face. The size of the muscle can be reduced with botulinum toxin injections into the apex of the masseter muscle. Treatment can also be used for people who suffer from bruxism, clenching or teeth grinding at night which can also cause headaches. Learn how to avoid mistakes when injecting masseter muscles with Botox.


Although this is in the upper face, the temporalis muscle is another muscle involved in chewing in the lower face. We therefore do not tend to treat the temporalis muscle, but you will note the visible contraction, alongside the masseter, if you ask your patient to clench their teeth together.


The nasalis muscle across the nose is responsible for causing little lines either side of and on the nose itself, known as bunny lines. You can treat these quite safely with two to four units of Botox on each side with placement near its origin on the bone.

Muscles in the neck


The platysma muscle runs all the way from the chest in an upwards direction eventually meshing with the superficial muscular aponeurotic system (SMAS) in the face. When you relax the platysma in the neck with botulinum toxin, it can have an unexpected benefit of subtly lifting the mid face in some patients. Primarily, treatment will help to achieve more definition around the jawline and soften vertical lines that develop the strands of muscle making them more visible. This muscle requires quite high doses if we want to relax the whole area across the neck.

For more guidance on the best botulinum toxin injection patterns, why not get your hands on Dr Tim Pearce’s 26 essential injection patterns for botulinum toxin. There are also some simple steps you can take to accelerate your facial anatomy knowledge and you can purchase Dr Tim’s limited edition facial anatomy posters for your aesthetic business as a helpful tool to understand the muscles of the face, the superficial fat pads, the arterial blood supply, the deep fat pads and ligaments, and the nerve supply to the face.

Did you enjoy this quick tutorial? Dr Tim loves to hear from his followers and share his anatomy knowledge; if you have any questions or ideas for topics he can cover in future videos, please drop him a comment on social media; you can find Dr Tim Pearce on Instagram.

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Aesthetics Mastery Show

Facial muscle anatomy in 10 minutes

In this episode, Dr Tim looks gives a 10 minute tutorial which is ideal for medical professionals in aesthetics, medical students or if you’re simply curious about anatomy in relation to aesthetics. Watch the full Aesthetics Mastery Show here.

The show has had thousands of views and a number of comments from practitioners and patients. The latest include:


“Thank you for being the best teacher out there. I’ve learnt so so much from you, Sir. May God reward you for all the knowledge that you impart for which others charge a morbidly high fee. Much love”


“What a brilliant VIDEO. Clear, concise and INFORMATIVE! Would love to see a video like this but on facial arteries, veins, etc…!”


“I love all your videos and find them very very helpful.”

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Dr Tim Pearce MBChB BSc (Hons) MRCGP founded his eLearning concept in 2016 in order to provide readily accessible BOTOX® and dermal filler online courses for fellow Medical Aesthetics practitioners. His objective was to raise standards within the industry – a principle which remains just as relevant today.

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