If you have spent any time researching facelift surgery, you have probably encountered the term SMAS. It comes up in descriptions of traditional facelifts, deep plane facelifts, and almost every conversation about how to lift the face without making the skin look pulled.
But the SMAS is not a facelift technique. It is part of your anatomy. The letters stand for superficial musculoaponeurotic system, a fibromuscular connective-tissue layer beneath the skin and superficial facial fat. Once you understand where it sits and how it is attached, the differences between facelift operations start to make more sense.
The SMAS is the structure we can work with. The retaining ligaments help determine how freely that structure can move.
BENEATH THE SKIN
Where Does the SMAS Sit in Your Face?
Imagine moving inward from the surface of your cheek. First there is the skin. Beneath it is superficial facial fat, which helps create the contours you see. The SMAS lies deeper than that superficial fat. Below and around it are additional connective tissues, facial spaces, retaining ligaments, muscles, and branches of the facial nerve.
Surgeons often describe the SMAS as the third layer of the face. That is a useful way to orient yourself, although the actual anatomy is more complex than five perfectly even layers stacked on top of one another. The SMAS changes in thickness, character, and its relationship to other structures as you move across the cheek and toward the neck.
The SMAS is not the skin, and it is not a single facial expression muscle. It is a fibromuscular system associated with those muscles and with the movement of the facial soft tissues.
The illustration highlights the SMAS, its relationship to the platysma in the neck, and examples of the retaining ligaments. It is an educational drawing rather than an exact surgical dissection map. The course of these tissues and their relationship to nearby nerves vary by facial region.
Why Does a Facelift Surgeon Work With the SMAS Instead of Just Pulling Skin?
Skin is important, but I don’t want it to do all the work of holding up a facelift. When facial tissues descend, the change involves more than the outer surface. Moving only the skin may make it look tighter without adequately repositioning the heavier tissues beneath it.
The SMAS gives me a deeper structural layer to work with. Depending on the operation, I may tighten it, fold it, elevate it, or reposition tissues associated with it. The skin can then be redraped over the improved contour rather than being treated as the primary support for the result.
Working with deeper support is one reason facelift surgery moved beyond the older concept of simply removing extra skin. It is also why two surgeries described as a “facelift” may involve very different work beneath the surface.
None of this means the SMAS is responsible for every visible change in an aging face. Changes in bone support, facial fat compartments, skin quality, and the neck all contribute. The SMAS is one crucial part of that larger anatomical picture.
INSIGHTS FROM DR. ATHRÉ
Watch Henrietta Demonstrate Why Ligament Release Changes SMAS Movement
Henrietta is my silicone facial model. I use her to show what happens when I pull on a simulated SMAS layer while it remains fixed at retaining-ligament points, and how its movement changes when those attachments are released. It is a mechanical demonstration of tissue mobility, not a clinical study comparing the durability of facelift procedures.
What Actually Stops the SMAS From Moving?
In the video, I pull on the layer represented by Henrietta’s silicone face. At first, it doesn’t travel very far, and the fold near the mouth doesn’t change as much as you might expect. The layer is still anchored at particular points.
Those points represent the facial retaining ligaments. They connect the mobile soft tissues of the face to deeper structures and help establish the normal shape of the cheek and jawline. The zygomatic retaining ligaments are associated with the cheekbone region; other important attachments include the masseteric and mandibular retaining ligaments.
Once I release the simulated attachment in the demonstration, the layer moves more freely. That is the central lesson: pulling harder and releasing a tether are not the same thing.
We have a separate, more detailed article on facial retaining ligaments and their role in deep plane facelift surgery. Here, the important point is how those attachments interact with the SMAS.
What Does It Mean to Tighten, Lift, or Release the SMAS?
Patients sometimes speak about a “SMAS facelift” as though it were one operation. It isn’t. Surgeons can manipulate this layer in several ways, and the words used to describe those maneuvers matter.
SMAS Plication
Plication uses sutures to fold or tighten the SMAS without necessarily elevating it as a separate flap. It can be useful in selected patients, depending on which tissues need correction and how much movement is required.
SMAS Imbrication or Flap Elevation
Other operations involve cutting and overlapping parts of the SMAS or raising a segment of the layer so it can be repositioned. The extent of elevation and the structures released vary by technique. These are not all equivalent operations simply because they involve the SMAS.
Deep Plane Dissection
A deep plane approach works beneath the SMAS in selected areas of the face. It can allow the surgeon to release retaining attachments and move portions of the overlying soft tissue more directly. This is the relationship I am demonstrating with Henrietta.
It is worth remembering that a deep plane facelift is still a surgery involving the SMAS. The terms aren’t opposites. One describes an anatomical structure; the other describes a plane and approach to dissection.
For a broader comparison of surgical methods, read my explanation of facelift techniques, including SMAS, deep plane, and mini facelift approaches. This article is deliberately focused on the anatomy rather than ranking procedure names.
How Does the SMAS Connect to the Platysma in the Neck?
The SMAS doesn’t simply stop at the jawline. There is important anatomical continuity between the superficial facial fascial system and the platysma, the broad, thin muscle of the neck.
That relationship helps explain why I often evaluate the face and neck together. When the lower face loses definition, I am looking not only at the cheek and jowl, but also at the structures immediately beneath the jaw. Repositioning tissues in the lower face may influence that transition.
But continuity doesn’t mean every neck problem can be corrected by moving the facial SMAS. Skin laxity, platysma banding, superficial fat, deep fat, prominent glands, and the hyoid’s position can each affect neck contour in different ways.
That is why an appropriate neck lift may involve work beyond the superficial facial layer, depending on what is creating the fullness or loss of definition.
Where Is the Facial Nerve Relative to the SMAS?
This is one reason I don’t want patients to think of the face as a simple stack of interchangeable layers.
Branches of the facial nerve travel in important relationships to the deeper facial tissues, and those relationships change as the branches cross different parts of the cheek, jawline, and neck. The safe surgical plane in one region cannot be assumed to be identical everywhere.
Working deeper is not automatically better, and working more superficially is not automatically safer. What matters is understanding the regional anatomy and choosing the dissection needed for the correction being made. Ligament release has to be precise, not indiscriminate.
The silicone model makes tissue movement easy to visualize. It cannot reproduce all the nerves, blood vessels, and anatomical variations a surgeon must account for during an actual operation.
What Can Repositioning the SMAS Change, and What Can’t It Change?
If a patient’s cheeks have descended or jowls have developed because of changes in soft-tissue position, working with the SMAS and its attachments may be an important part of restoring facial contour. Depending on the anatomy and technique, that can improve the transition through the cheek and jawline.
However, moving the SMAS doesn’t restore lost facial fat by itself. It doesn’t reverse changes in facial bone, and it doesn’t resurface fine wrinkles, sun damage, or crepey skin. A deep smile line also doesn’t disappear simply because a certain surgical plane was used; the result depends on the individual anatomy and the amount of safe tissue movement achieved.
When volume loss is a significant part of the problem, facial fat transfer may have a separate role. When skin texture is the main concern, skin-focused treatment is a different discussion. This is why I evaluate those changes independently, even when several treatments are ultimately combined.
Why Understanding the SMAS Doesn’t Tell You Which Facelift You Need
I can show a patient the same anatomical layer I have shown you here, but that doesn’t tell me how far I should dissect, which retaining ligaments I should release, or whether they need a facelift at all.
For one person, the main concern may be early jowling. For another, the cheek tissues have descended more significantly. Another may have relatively little facial descent but substantial fullness beneath the jaw. Those are different problems, and they should not all receive the same operation simply because the word “deep plane” has become popular.
When I discuss facelift surgery with a patient, I explain where I see the structural change, what I think can be repositioned, which areas may need separate treatment, and what the limits of surgery are. The technique comes out of that examination.
The SMAS tells me where I can work. Your anatomy tells me what I need to do.
For examples of how different surgical plans can affect the lower face and neck, you can explore my facelift before and after gallery. Many patients have more than one procedure, so the photographs should be understood in the context of their complete treatment plans.
FREQUENTLY ASKED
Frequently Asked Questions About the SMAS
These are the key points I want patients to understand when they encounter the term SMAS while researching facelift surgery.
What does SMAS stand for?
SMAS stands for superficial musculoaponeurotic system. It refers to a fibromuscular connective-tissue system beneath the superficial fat of the face. The term was established by Mitz and Peyronie in their 1976 anatomical study of the cheek and parotid region.
Where is the SMAS located beneath the skin?
In a commonly used surgical model, the SMAS is the third facial layer, situated beneath the skin and superficial fat and above deeper facial spaces and structures. Its precise form varies by location. A review of SMAS anatomy and regional continuity explains its relationship to superficial and deep facial fat.
Is the SMAS a muscle or a ligament?
Neither description is quite right. The SMAS is a fibromuscular fascial system associated with muscles of facial expression. Retaining ligaments are separate anchoring structures that interact with it. The anatomical review of the SMAS explains how these structures differ.
What do retaining ligaments have to do with the SMAS?
Retaining ligaments help stabilize facial soft tissues by connecting them to deeper structures. When tissue needs to be mobilized during a facelift, selected attachments may need to be released. A review of retaining ligaments in modern facelift surgery discusses how different approaches manage those attachments.
Does every SMAS facelift use the same technique?
No. Surgeons may fold, suture, overlap, elevate, or reposition the SMAS in different ways. A review of facelift history and surgical anatomy describes how these approaches developed. The term alone doesn’t specify exactly what will be performed.
Is a deep plane facelift the same as a SMAS facelift?
They are related but not identical descriptions. SMAS names the anatomical structure; deep plane refers to an approach that works beneath it in selected regions. Many different techniques engage the SMAS, as illustrated by the published description of a combined SMAS and deep-plane approach.
Do deep plane facelifts always have better results than SMAS techniques?
No study establishes that one technique is best for every patient. A systematic review and meta-analysis comparing SMAS and deep techniques found improvements with both, but the limited number of direct comparisons and differences among studies prevented definitive conclusions about relative effectiveness. The anatomy and how the technique is performed remain important.
Does the SMAS connect to the platysma muscle of the neck?
Yes. The superficial facial fascial system is continuous with the platysma inferiorly, although its structure varies by region. A review of facial soft-tissue anatomy describes that continuity and why it matters in surgical planning.
Is the facial nerve beneath the SMAS?
Facial nerve branches have complex relationships with the deeper facial tissues, and those relationships change by region. It is not safe to assume that every area beneath the SMAS has the same anatomy. A three-dimensional study of the marginal mandibular and cervical nerve branches illustrates the importance of regional surgical landmarks.
Can tightening the SMAS eliminate fine lines and restore lost volume?
Not by itself. SMAS repositioning primarily addresses selected structural and contour changes. Fine wrinkles, skin texture, fat loss, and skeletal aging involve other tissues and processes. A review of the multiple layers involved in facial aging helps explain why different concerns may require different treatments.
