SMAS Fusion Zones Determine the Subfascial and Subcutaneous Anatomy of the Human Face: Fascial Spaces, Fat Compartments, and Models of Facial Aging

The Human Superficial Fascia: A Narrative Review

In recent years, the interest in the comprehension of the fasciae has significantly grown, together with the necessity of finding a consensus for a terminology of the fasciae in the research and clinical fields. Furthermore, it is becoming necessary to categorize the various types of fascia (superficial, deep, visceral, neural) since they possess different anatomical characteristics, and are implicated in different pathophysiological pathways. While in the past we have described the deep/muscular fascia, the aim of this work is to summarize and catalog the information relating to the human superficial fascia (thickness, cellular end extracellular matrix component, innervation, vascularization).

Surface anatomy in dermatology: Part II-Impact on perioperative management, procedural technique, and cosmesis

This CME series reviews updated Delphi consensus surface anatomy terminology through the lens of common medical and procedural dermatology scenarios, helping to underscore high-yield points that can be readily integrated into clinical practice to support patient care. Part I of the series reviewed the current state of standardized surface anatomy, provided an illustrative review of consensus terminology, highlighted prominent landmarks that can aid in critical diagnoses, and related the importance of precise terminology to principles of medical management. Part II will utilize consensus terminology to heighten recognition of key landmarks in procedural dermatology to support optimal functional and aesthetic outcomes.

New anatomical findings in the mandibular body region: Two parts that make up bucco-mandibular space

Soft tissue spaces not only enable gliding by contraction of the facial muscles, but they also cause drooping of the superficial fat due to gravity in the upright position. This study was performed to clarify the structures around the bucco-mandibular space (BMS) and to apply this anatomical knowledge to clinical practice. Four sides of the face were dissected using a conventional gross anatomical dissection technique, and 10 sides (5 horizontal and 5 frontal sections) of the removed semi-facial soft tissue were dissected using the stretched tissue dissection (STD) method. Histological examination of the mandible was performed on two sides to confirm the findings of conventional gross anatomical dissection and STD. In all cases, both gross dissection and STD revealed that the BMS was composed of two parts. The superficial part was filled with adipose tissue containing nerves and vessels, including the marginal mandibular branch of the facial nerve, facial artery, facial vein, and mental nerve. We named this part the adipo-neuromandibular part. By contrast, the deep part was separated from the adipo-neurovascular part by facial deep fascia and composed of loose connective tissue. We named this deep part the loose connective tissue part. The STD method enabled us to obtain detailed anatomical findings of the mandibular region and elucidate two parts of the BMS in which the neurovasculature is distributed. We believe that these findings provide new insights into facial anatomy by resolving existing anatomical uncertainties and will contribute to safer surgical treatment in the facial region.

Surgical Anatomy of the Ligamentous Attachments in the Superoposterior Scalp Region

BACKGROUND

Hairline-lowering surgery has become increasingly popular in recent years, but little investigation into the surgical anatomy of the scalp has been performed.

OBJECTIVES

The aim of this study was to describe findings based on clinical observation and anatomic study of ligamentous attachments in the superoposterior region of the scalp.

METHODS

Six fresh cadaveric heads were dissected to identify connective tissue structures in the superoposterior scalp region. The areas of interest were along the sagittal suture towards the lambda, the obelion, and around the lambdoid suture. The location and dimensions of identified connective tissue attachments were documented with reference to described skeletal landmarks.

RESULTS

Three distinct structures could be identified: (1) a cylindrical structure that sits at the posterior end of the sagittal suture with the parietal foramina in its base. This ligamentous structure extends from the pericranium into the galea, causes dimpling in the skin, and contains emissary veins. As this fulfills the criteria for an osseocutaneous retaining ligament, the term "cranial retaining ligament" is proposed. (2) Anterior to this ligament a connective tissue thickening was identified running along the sagittal suture and blending into the ligament, for which the term "sagittal adhesion" is proposed. (3) Another adhesion was identified just superior to the lambdoid suture, posterior to the retaining ligament, for which the term "supralambdoid adhesion" is proposed.

CONCLUSIONS

Identification and better understanding of ligamentous structures in the superoposterior scalp allows for a safer and more effective advancement of the scalp in hairline-lowering surgery, which is a benefit to both patients and surgeons.

Investigating the Anatomic Location of Soft Tissue Fillers in Noninflammatory Nodule Formation: An Ultrasound-Imaging-Based Analysis

INTRODUCTION

Noninflammatory nodules may be persistent to dissolve. To evaluate the possible reasons, a case series of ultrasound images and medical data of patients who were prospectively referred with noninflammatory nodules were evaluated.

MATERIALS AND METHODS

A total of 27 patients with nodules but without signs of inflammation were included. All cases were assessed with an 18-MHz linear ultrasound device. Exact location of the filler material was noted. Relations with clinical data were analyzed using chi-square tests.

RESULTS

Early onset of complaints (<2 weeks) was found in 16 patients and late onset (>2 weeks) in 11. All patients had multiple nodules. In all cases, the filler nodule was found to be located inside the fascia. Extension to the subcutaneous tissue was seen in 8 cases and to the deeper planes in 5. In 14 cases, the filler material was completely located inside layers of the fascia, and migration was observed in 5 cases.

DISCUSSION

Accumulation of filler material in the superficial musculoaponeurotic system or fascia may be an important cause for the occurrence of persistent noninflammatory nodules, either by initial faulty injection technique or by later accumulation through the pathway generated with a needle or cannula. Ultrasound-guided injections are helpful to dissolve the nodule.

Three sublayers in the SMAS: Observations of facial soft tissue using the stretched tissue dissection method focusing on the SMAS

The characteristics of the superficial musculoaponeurotic system (SMAS), including the morphology of each part and the connection between tissues, remain controversial. The purpose of this study is to clarify the anatomy of the SMAS using our new dissection method. In this study, six hemi-sides of heads from formalin-preserved cadavers were used. Three were used for creating a horizontal section and three were used for creating the section along the axial line perpendicular to the surface of the skin, resulting in a gradual change from the coronal section at the lateral to the sagittal section at the median. The resected head was cut into slices with widths of 7 mm. The stretched tissue dissection method was performed by fixing a tissue slice to a board and pulling the skin outward to stretch the soft tissue. Blunt dissection was then performed under a microscope. The SMAS comprises three layers: superficial, intermediate, and deep. The superficial layer is a thin membrane directly connecting to the septa in the subcutaneous fat. The deep layer is the connective tissue in contact with the sub-SMAS structure. The layer surrounded by the superficial and deep layer of the SMAS is the intermediate layer, containing connective tissue, adipose tissue, and facial muscles. The detailed findings of the SMAS obtained using this method resolve theoretical discrepancies and provide important insight for the field of facial surgery.

Enhanced study of facial soft tissues using a novel large scale histology technique

The safety and effectiveness of facial cosmetic surgery procedures are dependent on detailed 3D understanding of the complex surgical anatomy of the face. Traditional, small sample size anatomical dissection studies have limitations in providing definitive clarification of the fascial layers of the face, and especially in their relationship with the facial nerve, and their reaction to surgical manipulation. The objective study of large tissue areas is required to effectively demonstrate the broader architecture. Conventional histology techniques were modified to handle extraordinarily large tissue samples to fulfill this requirement. Full-thickness soft tissue samples (skin to bone) of maximum length 18 cm, width 4 cm, and tissue thickness 1 cm, were harvested from 20 hemifaces of 15 fresh human cadavers (mean age at death = 81 years). After fixation, the samples were processed with an automated processor using paraffin wax for 156 h, sectioned at 30 μm, collected on gelatin-chromium-coated glass slides, stained with a Masson's Trichrome technique and photographed. Using this technique, excellent visualization was obtained of the fascial connective tissue and its relationship with the facial mimetic muscles, muscles of mastication and salivary glands in 73 large histological slides. The resulting slides improved the study of the platysma and superficial musculo-aponeurotic system (SMAS), the spaces and ligaments, the malar fat pad, and the facial nerve in relations to the deep fascia. Additionally, surgically induced changes in the soft-tissue organization were successfully visualized. This technique enables improved insight into the broad structural architecture and histomorphology of large-scale facial tissues.

Intraoral Approach to Fat Grafting Based on the Mimetic Muscle Unit

BACKGROUND

Recently, the concepts of anatomic-based fat grafting and mid-facial anatomy have been studied. However, there is no clear consensus on the optimal fat grafting technique. We aimed to introduce a novel intraoral approach to fat grafting based on mid-facial mimetic muscles, wherein a substantial amount of fat was injected into appropriate locations to increase patient satisfaction and decrease the need for additional surgical techniques.

METHODS

Sixty-four Asian women (mean age, 41.2 y) who had undergone fat grafting through the intraoral approach between 2014 and 2019 were enrolled. We sequentially performed the following steps: fat harvesting, centrifugation, and fat injection. All patients were followed at an outpatient clinic for 6 to 12 months. We obtained photographs of their face before and at 3 and 6 months postoperatively and conducted a 5-point scale questionnaire survey at the 2 time points postoperatively to evaluate the satisfaction of patients and surgeons. We divided the mid-facial areas into malar eminence, infraorbital, and nasolabial fold areas and evaluated the following items: volume consistency, softness, irregularity, and overall satisfaction.

RESULTS

Patients reported "satisfactory" for the postoperative results. There were only 2 cases of complication among the 64 cases which resolved spontaneously. The highest and lowest satisfaction were reported for the malar eminence and nasolabial fold areas, respectively.

CONCLUSIONS

Fat grafting through the intraoral approach based on the mimetic muscle unit is an effective and safe method for mid-facial rejuvenation.

Facial Soft Tissue Repositioning With Neuromodulators: Lessons Learned From Facial Biomechanics

BACKGROUND

Neuromodulators have proven efficacy in reducing facial rhytides and have also been reported to improve jawline contour and the appearance of platysmal bands. Lifting effects of the tail of the eyebrow are expected outcomes when targeting the lateral peri-orbital region underscoring the versatility of neuromodulator treatments.

OBJECTIVE

To analyze the clinical effectiveness of a novel neuromodulator-based injection algorithm with regards to its ability to reposition the middle and lower facial soft tissues.

METHODS

Seventy-five study participants (8 males, 67 females) with a mean age of 37.5 (8.5) years were injected with neuromodulators in the subdermal plane of the mandibular soft tissues following a standardized algorithm. Live rating of clinical appearance was performed, as well as volume change and skin vector displacement using 3-dimensional imaging at baseline, day 14 and day 30.

RESULTS

3-dimensional volume analysis revealed an increase in midfacial volume by 0.46 cc, and a decrease of the lower facial volume by 0.30 cc compared to baseline. Additionally, an improvement of midfacial fullness (change of 0.13) and jawline contour (change of 0.44) was reported on clinical rating scales at day 30 compared to baseline.

CONCLUSIONS

Facial soft tissues can be repositioned during the 30 days follow-up period following a neuromodulator treatment; this was reflected through an increase in middle facial volume as well as through a decrease in lower facial volume. The novel injection algorithm presented can provide a safe and effective option for patients desiring improvement of midfacial fullness and jawline contour with neuromodulator treatment alone.

The Use of Thermography as an Auxiliary Method for Monitoring Convalescence after Facelift Surgery: A Case Study

Although IR thermography is widely used in medical diagnostics, there are no reports that describe the use of IR thermography in the evaluation of post-plastic-surgery regeneration processes. The aim of the study was to evaluate the potential of thermography as a method which, among others, allows us to determine the location and extent of the inflammatory process, supporting the clinical evaluation of the patient’s convalescence after a facelift surgery using the SMAS technique. During the study and in order to monitor the convalescence process, the patient had a series of face thermograms performed before surgery and up to the 6th week after it. The healing process after surgery was multidirectional for the contralateral areas of the face, leading to thermal asymmetry lasting up to the 3rd week of convalescence. The lowest T_mean values for ROIs were recorded in week 3 of the study and then they gradually increased, in week 6 after surgery, to the following values: chin = 33.1 ± 0.72 °C; cheek left = 33.0 ± 0.26 °C; cheek right = 33.2 ± 0.51 °C; ZFL = 33.8 ± 0.45 °C; ZFR = 33.6 ± 0.74 °C; ZLL = 32.6 ±0.55 °C; ZLR = 32.3 ± 0.32 °C. The temperatures of these areas were still lower than the baseline values obtained before surgery by 0.5–1.4 °C. The usefulness of thermography in the evaluation of post-operative convalescence in facial plastic surgery procedures shows potential in the context of diagnostic assessment of the dynamics of changes in the healing process.

Treating Aging Changes of Facial Anatomical Layers with Hyaluronic Acid Fillers

The aging process affects every anatomical layer of the face. Improved knowledge of how aging occurs in each anatomical layer of the face has helped evolve the facial rejuvenation strategies with HA fillers. Understanding the age-related changes in the anatomical facial layers, including their time of onset and how the changes occur in the different tissue layers, an injector can provide much more targeted and refined HA filler treatments. As fillers’ use has increased, there has been a distinct shift away from procedures lifting the skin and SMAS. We can selectively target the anatomical facial layers with HA fillers for more refined and predictable outcomes. An extensive range of HA filler variants is now available. Each filler type is optimized and designed to be injected into specific tissue planes for the best results. Knowing the predictable aging changes in the different tissue layers of the face is crucial as this guides the optimum filler choice. Working knowledge of the individual characteristics of the numerous HA-based products allows for their effective placement in the correct layer. Familiarity with the correct HA product may also help to minimize the downtime and risk of adverse events.

Aging Process of Lateral Facial Fat Compartments: A Retrospective Study

BACKGROUND

Since 2007, when the anatomy of facial fat compartment was described, an increasing number of studies on the aging process of the compartment of cadavers has emerged.

OBJECTIVES

The authors evaluated the aging changes of lateral facial fat compartments on the same person.

METHODS

Sixty-three patients were included in this retrospective study. All patients had magnetic resonance imaging scans with at least 4 years apart. The authors targeted the fat compartments of the superficial temporal, subcutaneous temporal, and buccal fat pad, comparing the data on different time points.

RESULTS

The thickness of the subcutaneous temporal fat did not change significantly. The 3 diameters of the superficial temporal fat compartment all became thinner on the axial view (P < 0.05). On the sagittal view, the superficial temporal fat elongated from 38.89 mm to 43.74 mm (P < 0.05). The buccal fat compartment also lengthened from 68.73 mm to 74.39 mm (P < 0.05) and had a positive correlation with follow-up duration only.

CONCLUSIONS

The study revealed the fat compartment change on the same person with time. The temporal hollow mainly originates from the thinner part of the superficial temporal fat. The descending of the buccal fat pad aggravates the labiomandibular fold. By understanding the aging process more fully, we can rejuvenate our patients more naturally.

A Novel Volumizing Extended Deep-Plane Facelift: Using Composite Flap Shifts to Volumize the Midface and Jawline

Traditional superficial musculoaponeurotic system (SMAS) facelifting surgery uses a laminar surgical dissection. This approach does not treat areas of facial volume loss, and requires additional volume supplementation with fat grafting or fillers. The novel volumizing extended deep-plane facelift uses a composite approach to the facelift flap. By incorporating a platysma myotomy in the extended deep-plane flap, a novel composite transposition flap can be created that revolumizes the posterior jawline, recreating a defined convex jawline of youth. Special attention is paid to the deep anatomy of the face, and the need for release of the facial ligaments.

Morphological study of human facial fascia and subcutaneous tissue structure by region through SEM observation

Fascia of the facial area is contiguous between fat tissues of the subcutaneous and connective tissue layers and does not envelope the muscle surface like other parts of the human body. This structure is called the superficial musculoaponeurotic system (SMAS), which is accepted as an international anatomical terminology. This special structure is commonly used to pull facial muscles during plastic surgeries such as a face lift. Most reports regarding the facial subcutaneous tissue structure including SMAS are in the field of plastic surgery, and only a few studies from a morphological perspective has been reported. Since the facial fascia does not envelope the muscular surface layer which is different from the deep fascia found on the general skeletal muscle surface, a clear definition of this structure has not been established yet. The purpose of this study was to clearly identify the basic morphological structure of the subcutaneous tissue layer containing the SMAS three-dimensionally through a scanning electron microscope using dissected specimen rather than living subjects. Moreover, this study explores structural differences among seven aging facial areas; thereby further clarifying the properties of the structure and add clinical significance and considerations.

Facelift Part I: History, Anatomy, and Clinical Assessment

In this article, the authors aim to thoroughly describe the critical surgical anatomy of the facial layers, the retaining ligamentous attachments of the face, and the complex three-dimensional course of the pertinent nerves. This is supplemented with clarifying anatomic dissections and artwork figures whenever possible to enable easy, sound, and safe navigation during surgery. The historic milestones that led the evolution of cervicofacial rejuvenation to the art we know today are summarized at the beginning, and the pearls of the relevant facial analysis that permit accurate clinical judgment and hence individualized treatment strategies are highlighted at the end. The facelift operation remains the cornerstone of face and neck rejuvenation. Despite the emergence of numerous less invasive modalities, surgery continues to be the most powerful and more durable technique to modify facial appearance. All other procedures designed to ameliorate facial aging are either built around or serve as adjuncts to this formidable craft.

A Novel Extended Deep Plane Facelift Technique for Jawline Rejuvenation and Volumization

BACKGROUND

Jawline aging is a complex process. We believe loss of posterior jawline definition and volume depletion is an underappreciated factor in the aging face.

OBJECTIVES

The aim of this study was to describe a novel composite, rotational flap modification of an extended deep-plane rhytidectomy. We evaluated long-term efficacy on improving jawline contour and volumization of the posterior mandibular region overlying the gonial angle.

METHODS

We performed a prospective study on patients who underwent our modification of extended deep-plane rhytidectomy. We define and introduce the mandibular defining line, a new anatomic metric in evaluating the mandibular contour. We define the area of the posterior lower face overlying the gonion and mandibular angle as the gonial area. Using 3-dimensional photography, we quantify contour changes along the mandibular border and volume change along the gonial area.

RESULTS

Eighty-nine patients (178 hemifaces) were analyzed. The mean gonial area volume gained was 3.5 cc. Average follow-up was 19 months. There was a statistically significant change in the mean mandibular defining line from 7.1 cm preoperatively to 9.8 cm postoperatively. This represents a lengthening of the visual perspective of the mandibular contour of 2.7 cm.

CONCLUSIONS

Composite, rotational flap modification of extended deep-plane rhytidectomy provides significant long-term augmentation of volume to the posterior mandibular region and lengthens the visual perspective of the inferior mandibular contour, creating a more youthful jawline. In selected cases, this may obviate the need for other volumization procedures used to improve jawline contour, such as autologous fat grafting.

LEVEL OF EVIDENCE: 4

Anatomy of the Superficial Fascia System of the Breast: A Comprehensive Theory of Breast Fascial Anatomy

Supplemental Digital Content is available in the text.

Background:

It has been two centuries since Petrus Camper identified superficial fascia and over 175 years since Sir Astley Cooper wrote his book on the anatomy of the breast. In the 1990s, Ted Lockwood taught us the importance of the superficial fascia layers in body contouring procedures he pioneered. These descriptions, however, fail to explain the three-dimensional fascial system in the breast. The authors set out to discover and describe a theory of superficial fascia structures responsible for breast shape.

Methods:

The nature of the superficial fascia system that surrounds the breast and its attachments to the chest were studied in 12 cadaver breast dissections and in clinical cases of both cosmetic and reconstructive breast procedures.

Results:

The authors found a three-dimensional, closed system of fascia and fat surrounding the corpus mammae, which attaches to the skin by means of specialized vertical cutaneous ligaments, or Cooper ligaments, and which attaches to the chest wall by means of a three-dimensional zone of adherence at the breast’s periphery.

Conclusions:

The breast is shaped by a three-dimensional, fibrofatty fascial system. Two layers of this system surround the corpus mammae and fuse together around it, and anchor it to the chest wall in a structure we have called the circummammary ligament.

Bilayered Structure of the Superficial Facial Fascia

Background

The superficial facial fascia comprises the superficial musculoaponeurotic system (SMAS) and the temporoparietal fascia (TPF) and is regarded as a continuous monolayer. However, some evidence indicates that the superficial facial fascia consists of 2 layers in specific areas.

Objectives

The authors evaluated the superficial facial fascia for bilayered regions.

Methods

Twenty fresh cadavers (40 hemifaces) were dissected to observe the superficial facial fascia. Twelve cadavers were dissected to assess tensile strengths of the superficial and deep layers of the SMAS. Specimens were obtained from 2 cadavers for histologic analysis.

Results

The SMAS and TPF were separable into superficial and deep layers, with intervening areolar tissue. The deep TPF was continuous with the deep SMAS inferiorly and the subgalea anteriorly. The superficial orbicularis oculi was invested by the superficial SMAS, whereas the deep orbicularis and the platysma were invested by the deep SMAS. Thus, 2 key structures addressed in facial rejuvenation are positioned in different surgical planes.

Conclusions

Study results support the belief that the superficial facial fascia comprises 2 layers, with the superficial orbicularis oculi and platysma invested by different layers. These findings have implications for facial rejuvenation techniques that involve management of the SMAS and TPF.

Characterization of the Cervical Retaining Ligaments During Subplatysmal Facelift Dissection and its Implications

Background

The cervical retaining ligaments anchor the platysma and soft tissues of the neck to the deep cervical fascia and deeper skeletal structures. The cervical retaining ligaments tether the platysma and prohibit free mobilization and redraping of the platysma muscle in rhytidectomy. This ligament system has previously been described in the literature only qualitatively.

Objectives

To define the anatomic dimensions of the cervical retaining ligaments and their relation to the platysma muscle in order to better understand the cervical retaining ligament system and how it limits motion of the platysma during rhytidectomy.

Methods

Extended deep plane rhytidectomy was performed on 20 fresh cadaveric hemifaces. The extent cervical retaining ligaments were dissected and measured. The anterior extent (width) of the cervical ligament were recorded at three anatomic points on each hemiface: (1) at the level of the inferior border of the mandible; (2) at the top of the thyroid cartilage at the thyroid notch; and (3) at the level of the cricoid.

Results

The average width of the cervical retaining ligaments in the neck was 15.3 mm. The width significantly decreased as they became more inferiorly positioned from the top of the neck at the anatomic measurement points, measuring 17.1 mm, 16.1 mm, and 12.6 mm (P < 0.05).

Conclusions

The cervical retaining ligaments are the support mechanisms of the platysma muscle in the neck. While previously described in only a qualitative manner, this study quantifies the anterior extent of these ligaments and how they invest the lateral platysma muscle. As these ligaments tether the platysma for an average of 1.5 cm, lateral platysma elevation of this distance during rhytidectomy surgery can improve platysmal redraping during rhytidectomy and potentially improve neck rejuvenation.