Facial Asymmetry: Anatomy and Non-Surgical Correction
Understanding the structures, movement patterns, and treatment decisions behind a more balanced face.
Introduction: The visible difference is only the starting point
A patient points to a deeper fold on one side of the face. Another notices that one cheek appears flatter. A third feels that their smile looks uneven in photographs.
Each describes facial asymmetry, but the same treatment rationale will not necessarily apply to all three.
The clinical challenge is to connect the visible concern with the structures contributing to it. Before discussing correction, clinicians need to consider what they are observing: differences in volume, tissue position, muscle activity, skin quality, or a combination of these.
For doctors and nurses involved in aesthetic care, this is where facial asymmetry becomes particularly interesting. A treatment can change a contour, yet its value depends on whether it addresses the patient’s underlying presentation.
The narrative review by Lee and colleagues provides a useful starting framework, organising facial asymmetry into five clinical categories: volume-related, soft-tissue sagging, dynamic, superficial, and composite presentations.
Understanding these patterns helps turn an aesthetic observation into a reasoned clinical discussion.
Clinical Categories: Reading the Face Through Its Anatomy
Volume-related asymmetry: which compartment is contributing?
Facial fat is organised into distinct superficial and deep compartments. In the midface, these include superficial cheek compartments, the deep medial cheek fat, and the sub-orbicularis oculi fat, commonly abbreviated as SOOF. Their relationships with muscles, fascia, and retaining ligaments influence the contours seen at the surface.
This compartmental anatomy explains why assessment extends beyond identifying the deepest visible hollow.
Published midface injection guidance distinguishes deep structural support from superficial contour refinement. Deep placement may increase projection and support overlying tissue, while superficial placement addresses a different layer of the volume deficit. The appropriate approach depends on the structures involved.
Clinical reasoning example: a patient requests treatment for a deeper nasolabial fold on one side. A useful assessment question is whether the plan should address the fold itself, the neighbouring cheek, or both. The visible line should prompt investigation of its anatomical context before product selection.
Figure 1. 45-year-old female patient evaluated with PET-CT for lymphoma staging. Coronal PET-CT image (a) reveals incidentally detected FDG avid areas in bilateral nasolabial fat compartments (arrows). SUVmean = 4.6, SUVmax = 5.9. The areas appear mildly hyperdense on CT (arrows in b) and hardly enhancing on post-gadolinium T1 W fat saturated sequences (c, arrows). The patient had a history of silicone injections four years earlier. She had no filler-related symptoms
Soft-tissue sagging: volume and position are different treatment targets
The superficial musculoaponeurotic system, or SMAS, is an important anatomical reference for facial procedures. Superficial and deep fat compartments occupy different relationships to this layer, while retaining ligaments connect and stabilise facial tissues.
Ligament weakening, dermal changes, and altered fat distribution contribute to age-related descent. The resulting contour may therefore reflect both a change in volume and a change in tissue position.
For treatment planning, that distinction is consequential. A proposed intervention should have a clear purpose: restoring support, repositioning tissue, improving skin firmness, or refining a contour.
Consider a consultation in which one lower cheek looks heavier. Describing it simply as “the larger side” leaves the treatment rationale unresolved. The more useful discussion concerns what creates that appearance and which component can realistically be modified.
Dynamic asymmetry: the face must also be assessed in motion
A resting photograph captures only part of facial function. Assessment of facial palsy can include brow elevation, eye closure, smiling, puckering, and lower-lip depression, supported by photographs and video.
These movements help distinguish the actions of individual muscles. The depressor anguli oris and depressor labii inferioris, for example, have different roles in mouth-corner and lower-lip movement. Treatment planning therefore requires more detail than identifying “the stronger side.”
Following facial nerve injury, synkinesis may develop: an intended movement is accompanied by an unwanted contraction elsewhere. An example is involuntary eye narrowing during smiling. Clinical recommendations emphasise structured assessment and a treatment pathway that can include facial retraining and botulinum toxin.
This is a functional problem as well as an aesthetic concern. A cosmetic improvement should be evaluated alongside eye closure, oral competence, and the patient’s experience of movement.
Figure 2. The nine standard frontal views (beginning at top row, on the far left, respectively): face at rest, pucker, complete eye closure, brow elevation, grin, nose wrinkling, whistling, pouting and lower lip depression, and a profile view for the assessment of the platysma action.
Superficial and composite asymmetry: several layers may contribute
The review includes differences in skin texture, scars, and tone within its superficial category. Composite asymmetry describes overlapping contributors, such as volume loss, laxity, and muscular imbalance.
These categories are useful prompts rather than automatic treatment prescriptions. The next question is which component matters most to the patient—and which can be addressed with a proportionate intervention.
Non-Surgical Modalities: Connecting Mechanism With Technique
Dermal fillers: product, plane, and distribution all matter
Hyaluronic acid fillers differ in their physical properties. One commonly discussed parameter is G′, the elastic or storage modulus, which describes a gel’s resistance to deformation. However, product selection must be considered together with anatomy and technique.
Published midface guidance describes approaches including deep bolus placement, fanning, and treatment across multiple layers. These techniques serve different purposes: a focused deposit and a distributed contour treatment do not create the same tissue effect.
For asymmetry, this makes the intended correction particularly important. Is the clinician seeking projection, support, a smoother transition, or a combination? That goal should guide the treatment plan before deciding how much product to use.
The infraorbital region illustrates the importance of restraint. Superficial filler placement and overfilling can contribute to visible irregularities, oedema, and a bluish Tyndall effect. Product suitability and injection depth therefore require particular attention in this region.
Clinical reasoning example: when the patient’s concern is “one under-eye looks darker,” the consultation should establish what is creating that appearance before assuming that adding volume will resolve it.
Vascular anatomy: depth is part of safety
Facial arteries vary in course and depth, and connections between vascular territories mean that an intravascular filler event can affect tissue beyond the injection site.
Guidance recommends slow, low-pressure injection, small increments, and continuous observation for unexpected pain or colour changes. A negative aspiration result cannot reliably exclude intravascular placement; it should not be treated as proof that injection is safe.
Ultrasound adds another anatomical resource. High-frequency imaging can help identify facial vessels and neural structures, supporting a more individualised understanding of the treatment area. Its value depends on the operator’s ability to acquire and interpret the images accurately.
The practical learning point is that technique cannot be separated from anatomy. The entry point, instrument, tissue plane, and product behaviour belong within one coordinated decision.
Collagen stimulators: a different timeline for correction
The review discusses injectable PDO powder as a collagen-stimulating approach and acknowledges that clinical evidence for facial contouring and asymmetry remains emerging.
This creates an important distinction in patient education: what is expected immediately, and what is expected to develop later?
A treatment plan involving biostimulation should explain when reassessment will be meaningful and how improvement will be judged. An early photograph alone cannot answer whether the intended longer-term response has occurred.
The article’s positive discussion of PDO powder should also prompt critical reading of the underlying studies rather than an assumption that all collagen stimulators are interchangeable.
Figure 3. Representative clinical case of a female patient in her twenties treated at an aesthetic clinic in Korea, presenting significant facial asymmetry, primarily characterized by volume deficiency on the left side of the face. (A) Before procedure. (B) After a single session of non-invasive radiofrequency (RF) lifting combined with a collagen stimulator (PDO powder) administered via cannula. The circled areas in the patient photographs indicate the specific treatment sites, clearly illustrating substantial improvement in facial symmetry, volumetric restoration, and overall aesthetic balance following the combined procedure.
PDO threads: vectors, tissue engagement, and neighbouring structures
Thread lifting introduces a mechanical component to treatment. Its anatomical considerations include tissue planes, retaining ligaments, fat compartments, and the direction in which tissue is repositioned.
The temporal region, facial nerve branches, parotid gland, and parotid duct are relevant structures when planning thread trajectories. Anatomical literature also describes ultrasound as a tool for mapping structures and identifying complications.
For an asymmetrical presentation, the planning discussion should therefore extend beyond thread numbers. What tissue is being engaged? What vector is intended? How will the proposed movement affect the neighbouring contour?
Clinical reasoning example: if one jowl appears lower, the clinician needs to explain why a particular repositioning strategy is appropriate for that side. Copying the opposite side’s treatment pattern does not, by itself, establish the rationale.
Patient selection and follow-up also matter. The desired outcome should be assessed after the immediate procedural response has settled, using consistent documentation rather than relying solely on the first post-treatment image.
Figure 4. When these types of threads are anchored in these dense ligamentous tissues, they effectively engage the underlying soft tissues intended to be lifted. Even without additional anchoring points above, the threads caught within these ligaments can create a lifting effect, as if they were anchored further up. This leverages the natural strength and positioning of the ligaments to maintain the lift, showcasing the critical role of anatomical understanding in optimizing aesthetic outcomes in facial thread lifting procedures.
Figure 5. Representative clinical case from an aesthetic clinic in Korea of a female patient in her fifties presenting significant facial asymmetry due to left-sided facial nerve palsy, characterized by decreased muscular strength and pronounced skin laxity affecting the entire left side of the face. (A) Before procedure. (B) After a single session of PDO thread lifting applied to the whole face. The circled areas on the patient photographs indicate the specific treatment sites, illustrating immediate and substantial improvements in facial symmetry, muscle tone, skin tightening, and overall aesthetic balance following the procedure.
Energy-based devices: the target layer determines the treatment logic
Radiofrequency, focused ultrasound, and lasers should be discussed individually because they use different technologies and target tissues differently.
Microfocused ultrasound creates small thermal injury zones at predetermined depths, with the intention of stimulating collagen contraction and subsequent remodelling. A systematic review supports its potential for facial tightening while highlighting variation in study methods and the need for stronger evidence.
Microfocused ultrasound with visualisation allows the operator to inspect the treatment area before delivering energy. In a small observational study of 22 women, skin elasticity improved at 12 and 24 weeks, illustrating the delayed timeline of tissue remodelling. Those findings concern skin laxity; they do not establish equivalent efficacy for every type of facial asymmetry.
For clinicians, the useful question is specific: which tissue change is this device intended to produce in this patient?
A protocol should be justified by that target and the individual anatomy, rather than by a general promise of “facial balancing.”
Extracorporeal shockwave therapy: an emerging area to examine critically
The review also discusses extracorporeal shockwave therapy, or ESWT, through proposed regenerative effects associated with mechanical stimulation. Its role should be interpreted alongside the review’s acknowledged evidence limitations.
For doctors and nurses exploring emerging modalities, three questions are especially useful: were the outcomes measured objectively, did the participants have the same clinical concern, and was follow-up long enough to assess durability?
Biological plausibility is a reason to investigate further. Treatment decisions also require convincing clinical evidence.
Advantages: Flexibility With a Defined Clinical Goal
Non-surgical treatment offers several ways to approach selected concerns, but the advantage becomes meaningful only when the plan is specific.
The patient should understand what is being addressed, what change is realistically expected, and what may remain visible. Consent and counselling are central to risk reduction, alongside appropriate patient selection, preparation, and injection technique.
For nurses working within their authorised scope, this creates valuable opportunities to support consistent photography, reinforce aftercare, document patient concerns, and facilitate timely review.
Complication preparedness is equally important. Consensus recommendations emphasise ready access to hyaluronidase for HA-related complications, clear instructions, and specialist contact pathways. The entire team should understand how to escalate a concern promptly.
Discussion and Limitations: Improvement Requires More Than a Photograph
The review’s illustrative cases show possible clinical applications, but they cannot establish comparative effectiveness. Its limitations include heterogeneous studies, predominantly small observational reports, and no formal risk-of-bias assessment.
When examining a before-and-after result, clinicians should ask what was measured, whether expression and positioning were consistent, and when the follow-up image was taken.
The same discipline applies to dynamic asymmetry. International recommendations for synkinesis place facial training at the beginning of a staged pathway, with botulinum toxin and selected surgical approaches considered according to the presentation and response.
This reinforces the value of matching the intervention to the clinical problem and assessing function alongside appearance.
From Recognising Asymmetry to Understanding Its Correction
Facial asymmetry is a rewarding subject for clinical learning because it brings anatomy, observation, technique, and patient communication into the same consultation.
The deeper learning lies in explaining the decision: why this structure is the target, why this modality is appropriate, and how its effect will be evaluated.
For doctors and nurses developing their aesthetic knowledge, the review offers a starting point for exploring those decisions. Read its clinical examples alongside the anatomical literature—and examine the reasoning that connects the presentation to the proposed correction.
Reference:
Clark, N. W., Pan, D. R., & Barrett, D. M. (2023). Facial fillers: Relevant anatomy, injection techniques, and complications. World Journal of Otorhinolaryngology–Head and Neck Surgery, 9(3), 227–235. https://doi.org/10.1002/wjo2.126 PubMed
Contini, M., Hollander, M. H. J., Vissink, A., Schepers, R. H., Jansma, J., & Schortinghuis, J. (2023). A systematic review of the efficacy of microfocused ultrasound for facial skin tightening. International Journal of Environmental Research and Public Health, 20(2), Article 1522. https://doi.org/10.3390/ijerph20021522 the University of Groningen research portal
de Sanctis Pecora, C., & Shitara, D. (2021). Botulinum toxin type A to improve facial symmetry in facial palsy: A practical guideline and clinical experience. Toxins, 13(2), Article 159. https://doi.org/10.3390/toxins13020159 PubMed
Goodman, G. J., Liew, S., Callan, P., & Hart, S. (2020). Facial aesthetic injections in clinical practice: Pretreatment and posttreatment consensus recommendations to minimise adverse outcomes. Australasian Journal of Dermatology, 61(3), 217–225. https://doi.org/10.1111/ajd.13273 PubMed
Guntinas-Lichius, O., Prengel, J., Cohen, O., Mäkitie, A. A., Vander Poorten, V., Ronen, O., Shaha, A. R., & Ferlito, A. (2022). Pathogenesis, diagnosis and therapy of facial synkinesis: A systematic review and clinical practice recommendations by the international head and neck scientific group. Frontiers in Neurology, 13, Article 1019554. https://doi.org/10.3389/fneur.2022.1019554 University of Helsinki Research Portal
Hong, G.-W., Kim, S.-B., Park, Y., Park, S. Y., Chan, L. K. W., Lee, K. W. A., Sydorchuk, O., Wan, J., & Yi, K.-H. (2025). Anatomical considerations for thread lifting procedure. Journal of Cosmetic Dermatology, 24(1), Article e16618. https://doi.org/10.1111/jocd.16618 PubMed
Kerscher, M., Nurrisyanti, A. T., Eiben-Nielson, C., Hartmann, S., & Lambert-Baumann, J. (2019). Skin physiology and safety of microfocused ultrasound with visualization for improving skin laxity. Clinical, Cosmetic and Investigational Dermatology, 12, 71–79. https://doi.org/10.2147/CCID.S188586 Dove Medical Press
Lee, C., Chae, S., Kwon, H.-J., Jeong, W., Lee, K. K., & Chae, M. (2025). Non-surgical correction of facial asymmetry: A narrative review of non-surgical modalities and clinical case examples. Journal of Clinical Medicine, 14(24), Article 8828. https://doi.org/10.3390/jcm14248828 pubmed.ncbi.nlm.nih.gov
Mundada, P., Kohler, R., Boudabbous, S., Toutous Trellu, L., Platon, A., & Becker, M. (2017). Injectable facial fillers: Imaging features, complications, and diagnostic pitfalls at MRI and PET CT. Insights into Imaging, 8(6), 557–572. https://doi.org/10.1007/s13244-017-0575-0 PubMed
Murray, G., Convery, C., Walker, L., & Davies, E. (2021). Guideline for the management of hyaluronic acid filler-induced vascular occlusion. The Journal of Clinical and Aesthetic Dermatology, 14(5), E61–E69. https://pmc.ncbi.nlm.nih.gov/articles/PMC8211329/ PubMed
Trévidic, P., Kaufman-Janette, J., Weinkle, S., Wu, R., Dhillon, B., Antunes, S., Macé, E., & Maffert, P. (2022). Injection guidelines for treating midface volume deficiency with hyaluronic acid fillers: The ATP approach (anatomy, techniques, products). Aesthetic Surgery Journal, 42(8), 920–934. https://doi.org/10.1093/asj/sjac007 PubMed
Wu, W.-T., Chang, K.-V., Chang, H.-C., Kuan, C.-H., Chen, L.-R., Mezian, K., Ricci, V., & Özçakar, L. (2022). Ultrasound imaging of facial vascular neural structures and relevance to aesthetic injections: A pictorial essay. Diagnostics, 12(7), Article 1766. https://doi.org/10.3390/diagnostics12071766
Master the Korean approach to facial balance with
anatomy-led planning, injectables, threads and energy-based technologies:
IFAAS Mini Fellowship (Hands-On)
Korean Advanced Non-surgical Face Lifting, using Thread Lifting
Combined with Aesthetic Injectables & Devices
6-7 March, 2027 - Seoul, South Korea - [Register Now]
More Upcoming Global Events
Comments