Lee Walker Facial Aesthetics Academy

💉 HOW DEEP IS THE MENTALIS MUSCLE?

We often talk about treating the mentalis with botulinum toxin… but how deep is the actual muscle target?

📊 Cadaveric and ultrasound data give us some useful numbers.

At approximately 5 mm lateral to pogonion:

👉 Mean depth from skin to the superficial surface of mentalis
6.7 ± 1.4 mm

👉 Mean mentalis muscle thickness
4.0 ± 1.4 mm

👉 Mean distance between the deep surface of mentalis and bone
1.1 ± 1.0 mm

This means the mentalis occupied an approximate depth range of:

🔥 6.7 to 10.7 mm beneath the skin

The muscle was also found predominantly:

📍 5 to 10 mm lateral to the facial midline

📍 20 to 30 mm inferior to a horizontal line connecting the oral commissures

And interestingly… mentalis morphology was not identical between individuals.

🧠 86.4% demonstrated a three dimensional dome shaped morphology
🧠 13.6% demonstrated a flatter morphology

So why does this matter?

Because the mentalis is not simply a superficial chin muscle.

A very superficial botulinum toxin injection may influence the superficial fibres… but may not optimally target the deeper muscle belly.

Conversely, touching bone does not mean you are necessarily intramuscular… there is approximately 1 mm of tissue between the muscle and periosteum in the studied population.

💡 Depth matters. Anatomy matters. And anatomy varies.

These measurements should guide our understanding… not become another rigid injection recipe.

REFERENCE

Choi DY, Bae JH, Youn KH, et al. Effective locations for injecting botulinum toxin into the mentalis muscle: cadaveric and ultrasonographic study. Toxins. 2021;13(2):96.

🧬 CAN BEAUTY REALLY BE CALCULATED?

Look at these two faces… 👀

One is the original.
The other has been digitally altered towards supposedly more “ideal” facial proportions.. including symmetry.. facial proportion and "golden ratio"

But which is actually more beautiful?

📐 For centuries we’ve tried to define facial beauty mathematically…

✨ Facial thirds
✨ Facial fifths
✨ Symmetry
✨ Neoclassical canons
✨ The Golden Ratio… 1.618

The problem?

There is no universally accepted mathematical formula for facial beauty.

Research suggests attractiveness is influenced by multiple interacting factors including symmetry, averageness, s*xual dimorphism, skin quality, age, ethnicity and individual preference.

And the famous Golden Ratio?

Despite its popularity in aesthetics, evidence that attractive faces consistently conform to φ = 1.618 is far from convincing.

Perhaps the biggest danger in aesthetic medicine is believing that every face should be moved towards the same mathematical ideal.

💉 We shouldn't be treating numbers. We should be treating faces.

Beauty may have proportions…

But it doesn't have a formula. 🧬

FacialAssessment AestheticEducation BeautyScience

⚠️ THE ZYGOMATICO ORBITAL ARTERY… AN UNDERESTIMATED VESSEL OF THE TEMPLE

When we think about vascular risk in the temple, most injectors immediately think superficial temporal artery.

But the zygomatico orbital artery (ZOA) deserves considerably more attention. 👀

🔴 The ZOA is present in approximately 85 to 93% of studied specimens, although considerable anatomical variation exists.

🔴 It most commonly originates from the superficial temporal artery or its frontal branch, then travels anteriorly towards the lateral orbital region.

🔴 One anatomical study demonstrated that when present, the ZOA travelled within 1 cm of a line connecting the tragus to the superciliary arch… a useful surface landmark to remember.

🔴 Its reported diameter is not insignificant. One CT/cadaver study reported a mean diameter of 1.2 ± 0.2 mm, while another anatomical investigation reported a mean of 2.52 mm.

⚠️ But here is the important bit…

The ZOA has extensive anastomoses around the lateral orbital rim and has documented communication with branches of the ophthalmic arterial circulation, including supraorbital, lacrimal and palpebral territories.

So an artery originating from the external carotid circulation can communicate with the internal carotid / ophthalmic circulation.

That makes understanding this vessel particularly relevant when treating the temple and lateral orbital region.

👉 The temple isn't just a hollow to fill.

It is a multilayered vascular territory with considerable anatomical variation.

Know the vessel… understand the connections… respect the anatomy. 🧠💉

References

1. Park HJ, Lee JH, Jung W. The Superficial Temporal Artery and Zygomatico Orbital Artery: Superficial Arterial Distribution of the Anterior Temple Area. Biomed Res Int. 2022;2022:3790546.

2. Chen CL, Zhou YH, Luo CE, Wang HB, Luo SK. Zygomatico Orbital Artery: A Reevaluation of the Temporal Blood Vessels. Plast Reconstr Surg. 2023;151:1180–1185.

3. Topographic Anatomy of the Zygomatico Orbital Artery: Implications for Improving the Safety of Temporal Augmentation. Plast Reconstr Surg. 2021.

4. Anatomical Insight into the Zygomatico orbital Artery Using 3 Dimensional Compu

⚠️ THE TRANSVERSE FACIAL ARTERY… DOES IT REACH FURTHER THAN YOU THINK?

We talk constantly about the facial artery in aesthetic medicine…

But how often do you think about the transverse facial artery? 🩸

Usually arising from the superficial temporal artery, the TFA travels across the lateral face… but its perforators may be far more clinically relevant than many injectors realise. 👀

🔬 Recent anatomical research found:

📍 TFA perforators in 96% of hemifaces
📍 91.3% had a single dominant perforator
📍 Mean emergence 31.7 mm lateral to the lateral canthus
📍 Mean emergence 40.3 mm inferior to the lateral canthus
📍 Mean depth 11.3 mm

But here's the important part…

The vessel can cross the SMAS and contribute to a superficial subdermal vascular plexus approximately 3 to 5 mm deep. 🩸

👁️ AND THE LOWER EYELID?

An anatomical study specifically investigating the TFA perforator for lower eyelid reconstruction demonstrated its vascular contribution towards this region.

Another large anatomical study found the TFA in 96% of cases, with a mean diameter of approximately 1 mm… but vessels up to 2.2 mm were identified.

So when we're injecting the…

💉 Lateral cheek
💉 Zygoma
💉 Lid cheek junction
💉 Inferolateral orbit
💉 Preauricular region

…perhaps we shouldn't automatically think “low vascular risk.”

The TFA teaches us something important…

A vessel can begin deep… cross anatomical planes… and become superficial.

🧠 Deep ≠ vessel free.

Lateral face ≠ avascular face.

Perhaps the vessels we talk about least are the ones we need to understand better. 🔬

📚 REFERENCES

Anatomical Characterization of Transverse Facial Artery Perforators: A Micro computed Tomography and Cadaveric Study. Aesthetic Surg J. 2026;46(8):921–926.

Yamakawa S, Suda S, Hayashida K. A new lower eyelid reconstruction using transverse facial artery perforator flap based on an anatomical study. J Plast Reconstr Aesthet Surg. 2023;77:39–45.

Koziej M, P***k J, Wnuk J, et al. The transverse facial artery anatomy: implications for plastic surgery procedures. PLoS One. 2019;14(2):e0211974.

Schaverien MV, Pessa JE, Saint Cyr M, Rohrich RJ. The arterial and venous anatomies of the lateral face

⚠️ THE FACIAL VEIN… THE VASCULAR DANGER WE DON’T TALK ABOUT ENOUGH

When we teach vascular safety in aesthetic medicine, we overwhelmingly focus on arteries…

Occlusion. Necrosis. Blindness.

But what happens when filler enters a vein? 🩸

Venous anatomy presents a completely different set of potential problems…

🔹 Venous embolisation
Material entering the venous circulation has the potential to travel away from the injection site and towards the central circulation.

🔹 Orbital and intracranial connections
The angular and facial venous systems communicate with the ophthalmic veins and ultimately the cavernous sinus.

🔹 Deep facial connections
The facial vein communicates with the deep facial vein and pterygoid venous plexus… connecting superficial and deep venous networks.

🔹 Venous obstruction
Trauma, compression, thrombosis or intravascular material may compromise venous drainage… potentially producing congestion, swelling and dusky discolouration rather than the classical appearance of arterial ischaemia.

🔹 Bruising and haematoma
Probably the complication we encounter most frequently… but certainly not the only reason facial veins matter.

🧠 Perhaps our vascular education has become too arterial.

Facial veins are not simply blue versions of arteries.

They have different anatomy… different haemodynamics… different connections… and potentially very different complications.

We need to understand where blood is going… not simply where it is coming from.

Know the arteries. Know the veins. Know the connections. 🩸

📚 References

Isaac J, Walker L, Ali SR, Whitaker IS. Exploring the venous supply of the face: An illustrated overview of contemporary literature. JPRAS Open. 2025;43:92–104.

Zhang J, Stringer MD. Ophthalmic and facial veins are not valveless. Clin Exp Ophthalmol. 2010;38(5):502–510.

Lohn JWG, Penn JW, Norton J, Butler PEM. The course and variation of the facial artery and vein: implications for facial transplantation and facial surgery. Ann Plast Surg. 2011;67:184–188.

MedicalEducation PatientSafety

📐 MALE vs FEMALE GONIAL ANGLE...

We often hear that the ideal male jaw should be extremely square... almost 90°... while a female jaw should simply be more obtuse 120°+

The evidence says otherwise 👇

👨 Male mandibles tend to have greater bigonial width, larger ramus dimensions and more robust morphology.

👩 Female mandibles tend to be smaller, narrower and have a more tapered lower facial contour.

But interestingly... gonial angle itself is not a reliable discriminator of s*x.

Studies are inconsistent and a 2024 systematic review found no significant overall difference between males and females.

What about attractiveness?

Mommaerts investigated preferences for the ideal male jaw and found:

▪️ Gonial angle approximately 130° ▪️ Intergonial width ≈ facial width ▪️ Gonion around the oral commissure ▪️ Relatively horizontal mandibular border ▪️ Defined... but not excessively pointy

So the attractive masculine jaw isn't necessarily 90°... and a feminine jaw isn't simply “more obtuse.”

🧠 Sexual dimorphism describes population tendencies... aesthetic preference describes what observers find attractive.

Treat the facial phenotype... not an angle.

📚 Mommaerts MY. J Craniomaxillofac Surg. 2016;44:381–391. 📚 Hazari P et al. J Forensic Dent Sci. 2016. 📚 Sella Tunis T et al. J Forensic Leg Med. 2016. 📚 Role of Mandibular Parameters in Gender Determination: Systematic Review & Meta Analysis. 2024.

🧬 LATE ONSET NODULES... ARE WE STILL OVERSIMPLIFYING THEM?

Late onset nodules following hyaluronic acid filler are often discussed as though they represent a single complication.

They don't.

🔬 A nodule appearing weeks or months after treatment may represent:
🦠 Infection
🔥 Delayed inflammatory reaction
🧬 Foreign body granulomatous response
💉 Product accumulation or malposition
🦷 Inflammation triggered by infection or another immune stimulus

❓ Or a combination of mechanisms

And this distinction matters... because not every nodule should be treated the same way.

The old debate of “infection vs inflammation” is probably too simplistic.

Biofilm has historically been proposed as an explanation for many delayed reactions... but demonstrating bacterial DNA doesn't necessarily establish causation.

Equally... calling every delayed nodule an immune mediated reaction risks overlooking infection.

⚠️ Before reaching for steroids... think.

Is it inflammatory?
Is infection plausible?
Is it fluctuant?
Is there evidence of abscess formation?
Is there dental or systemic infection?
What product was injected... where... how much... and when?

Ultrasound can also be extremely useful when the diagnosis isn't clinically obvious.

💡 The diagnosis should drive the treatment... not the other way around.
Delayed nodules remain an area where our terminology and evidence base continue to evolve.

❓ QUESTION FOR DISCUSSION
Do we need to stop treating late onset nodules as a diagnosis... and start treating it as a clinical presentation requiring a diagnosis?

📚 REFERENCES
Beleznay K et al. Delayed-onset nodules secondary to a smooth cohesive 20 mg/mL hyaluronic acid filler. Dermatol Surg. 2015.
Artzi O et al. Delayed inflammatory reactions to hyaluronic acid fillers. Dermatol Surg. 2020.
Snozzi P, van Loghem JAJ. Complication management following rejuvenation procedures with hyaluronic acid fillers. Plast Reconstr Surg Glob Open. 2018.
Signorini M et al. Global Aesthetics Consensus: avoidance and management of complications from hyaluronic acid fillers. Plast Reconstr Surg. 2016.

⚠️ THE GLABELLA... A SMALL AREA WITH VERY HIGH CONSEQUENCES

👁️ The glabella remains one of the highest risk anatomical regions for filler induced visual loss.

Why?

🩸 Because the vascular anatomy communicates directly with the ophthalmic circulation.

We often focus on the supratrochlear and supraorbital arteries... but the anatomy is considerably more complex.

🔴 Central arteries 🔴 Paracentral arteries 🔴 Supratrochlear arteries 🔴 Supraorbital arteries 🔴 Dorsal nasal and angular communications

Recent ultrasound anatomy identified central arteries on approximately 45% of sides examined and paracentral arteries on approximately 62%.

So simply avoiding the expected course of the supratrochlear artery does NOT mean you have avoided the vascular anatomy.

👁️ AND THIS MATTERS...

The 2024 review by Doyon et al identified 365 new cases of filler associated visual loss.

Of the reported injection sites...

👃 Nose 40.6% 🧠 Forehead 27.7% ⚠️ Glabella 19.0%

And when visual outcome was available...

❌ 68.2% had no visual recovery ⚠️ 25.8% had partial improvement ✅ Only 6% achieved complete visual recovery

Important... this does NOT mean 19% of glabellar injections cause blindness.

It means 19% of the reported cases of filler associated visual loss originated from injections in the glabella.

The glabella isn't simply two supratrochlear arteries.

It is a variable interconnected vascular network with direct access to the ophthalmic circulation.

QUESTION FOR DISCUSSION 👇

Knowing what we now know about the anatomy and the consequences of vascular embolisation...

Should we still be routinely injecting filler into the glabella?

📚 REFERENCES

Doyon VC et al. Update on Blindness From Filler: Review of Prognostic Factors, Management Approaches, and a Century of Published Cases. Aesthetic Surgery Journal. 2024.

Siperstein R et al. Dangerous and Under Recognized Arteries of the Glabella: An Ultrasound Study of Central and Paracentral Arteries and Risk During Filler Injection. Dermatologic Surgery. 2025.

Beleznay K et al. Update on Avoiding and Treating Blindness From Fillers: A Recent Review of the World Literature. Aesthetic Surgery Journal. 2019.

🧠 The Feynman Technique... every educator in aesthetic medicine should use this.

One of the biggest mistakes we make as educators... is assuming that because a delegate can repeat our words... they understand the concept...

They don't...

Real understanding is being able to explain it simply... without the slides... without the textbook... and without the lecturer...

💡 Richard Feynman believed that if you can't explain something in simple language... you probably don't understand it well enough yourself...

As educators... try this instead...

📍 Ask your delegates to explain... Why does filler spread...?

📍 Ask them to teach... How does a vascular occlusion occur...?

📍 Ask them to simplify... Why doesn't aspiration always work...?

If they struggle... you've identified a learning gap...

🎯 Teaching isn't about delivering information...
It's about exposing misunderstanding... then helping delegates rebuild their knowledge from first principles...

The best educators don't create students who can memorise...

They create clinicians who can think...

👇 Question for discussion...

What's one concept in aesthetic medicine that every educator should be able to explain in under 60 seconds... without using jargon?

📚 Reference

Feynman RP. The Pleasure of Finding Things Out. Perseus Books. 1999.

Myth or reality...? 🤔

One of the most persistent beliefs in aesthetic medicine is that larger botulinum toxin complexes diffuse less and are therefore safer.

Current evidence does not support this as a clinically meaningful determinant of the field of effect. Following reconstitution and physiological dilution... complexing proteins dissociate from the 150 kDa neurotoxin and are not thought to influence clinical diffusion.

Instead... the available evidence suggests that the field of effect is determined predominantly by dose... injection technique... injection depth... injection volume... anatomical factors... and patient specific characteristics rather than molecular complex size alone.

This doesn't mean all botulinum toxin formulations behave identically. Different products have distinct manufacturing processes... excipients... biological potency... and clinical profiles.

However... attributing differences in clinical spread solely to molecular complex size is not supported by the current evidence.

As clinicians... we should be careful not to confuse biological plausibility with clinical evidence. Our patients deserve decisions based on robust science rather than assumptions.

What do you think...? Has the evidence changed your understanding of toxin diffusion...? 🤔🤔🤔🤔

References • Pickett A. Complexing proteins and the diffusion of botulinum neurotoxin type A: fact and fiction. • Ramirez-Castaneda J et al. Diffusion, spread and migration of botulinum toxin. Movement Disorders. 2013. • Albanese A et al. A systematic review on botulinum neurotoxin type A formulations. Toxicon. 2015. • Benecke R. Clinical relevance of botulinum toxin accessory proteins. European Journal of Neurology. 2012.