An Anatomical Study of the Nasal Superficial Musculoaponeurotic System

8/3/2019 An Anatomical Study of the Nasal Superficial Musculoaponeurotic System

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ORIGINAL ARTICLE

An Anatomical Study of the Nasal SuperficialMusculoaponeurotic System

Surgical Applications in Rhinoplasty

Yves Saban, MD, PhD; Chiara Andretto Amodeo, MD; Jean Claude Hammou, MD; Roberto Polselli, MD

Objective: To give a unifying description of nasal musclesand ligaments corresponding to anatomical and surgi-cal findings such as the dermocartilaginous ligament de-scribed by Pintanguy in 2001.

Methods: In 30 fresh cadavers of white individuals, na-sal dissections were performed, divided into 3 differentapproaches: from radix to nasal tip, from nasal tip to ra-dix, and from midline to lateral. The anatomical and sur-gical planes of dissection were followed to isolate the na-

sal superficial musculoaponeurotic system (SMAS).Correlations between thenasal SMAS andthenasal frame-work were noticed. In 9 specimens, the left nasal wallwas resected for histologic examination.

Results: The nasal SMAS consists of a unique layer, andit divides at the level of the nasal valve into deep and su-

perficial layers. Each layer has medial and lateral com-ponents. The dermocartilaginous ligament correspondsto the deep medial expansion. Both the deep and the su-perficial medial expansions correspond to the loweringligaments of the nasal tip; the cephalic rotation of the na-sal tip is allowed by their cut. The histological examina-tion showed that the deep lateral expansion is com-posed of fat.

Conclusions: This description of the nasal SMAS ex-plains the relationshipbetween the nasal musclesand liga-ments, including the dermocartilaginous ligament de-scribed by Pitanguy. Furthermore, it is helpful to surgeonsduring rhinoplasty.

Arch Facial Plast Surg. 2008;10(2):109-115

M

ANYARTICLES HAVE DIS-c u s s e d t h e n a s a lmuscles, which formthe so-called nasal su-perficial musculoapo-

neurotic system (SMAS). The insertionsand the functions of these muscles havebeen widely described,1-3 but, in our opin-ion, there is a lack of a united concept of muscles and ligaments of the nose. Wedemonstrate:

1. The existence of the nasalSMAS, ananatomical structure that unifies the dif-ferent muscular and ligamental anatomi-cal components overlying the bony andcartilaginous nasal framework;

2. That this anatomical structure is acontinuous layer that extends from thegla-

bellar region to the nostril margin;3. That at the level of the internal na-sal valve it is possible to identify a super-ficial and a deep nasal SMAS layer, eachone with medial and lateral components.

Basing our opinion on many cadaverdissections performed during the seniorauthor’s (Y.S.) surgical and anatomical ca-reer, we hypothesize that the nasal SMASdoes exist and that the ligament de-scribed by Pitanguy4 in 2001 ispart ofthis

whole structure; in particular, it would bethe deep medial expansion of the nasalSMAS. Anatomical explanations have acritical impact on surgical procedures be-cause to obtain the best nasal tip defini-

tion and rotation, it is necessary to oper-ate on the components of the nasalSMAS.5,6 From the methodological pointof view, it is fundamental to perform thedissection of this area using the anatomi-cal approach and not the surgical ap-proach. In fact, the surgical approachcausesthe disruption of the anatomical na-sal structuresand makes thestudy and de-scription of them impossible. Further-more, dissection can be performed indifferent planes. Five distinct layers abovethe cartilaginous and bony nasal struc-

ture have been described7,8

; we havefound the same layers: the skin, the su-perficial areolar layer, the fibromuscularlayer, the deep areolar layer, and theperichondral (periosteal) layer. The dis-section can be performed in the subcuta-neous, sub-SMAS, and subperichondralplanes. The plane of the dissection influ-ences the understanding of the links be-tween the anatomical components of thenasal SMAS.

Author Affiliations:Department of Ear, Nose, andThroat and Facial PlasticSurgery, CliniqueSt Antoine, Nice, France.

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METHODS

This study was divided into (1) a cadaver dissection section and(2) a histologic analysis section using light microscopic ex-amination of fresh nasal tissue excised from the nasal lateralwall of 9 specimens.

CADAVER DISSECTION

Detailed dissections were performed at the anatomy labora-tory at the School of Medicine, University of Nice, Nice, France.For this study, 30 white fresh cadavers were examined. The dis-sections were performed in 3 different anatomical planes: thesubcutaneous, the sub-SMAS, and the subperichondral. Threedifferent approaches were used: the radix to nasal tip (cranio-

caudal) approach, the nasal tip to radix (caudo-cranial) ap-proach, and the midline to lateral approach.1. In 10 specimens, the skin was incised in the midline. In

5 specimens, the dissection was performed on the right side of the specimens in the subdermal, proceeding from the midlinelaterally. In another 5 specimens, the same procedure was per-formed on the left side. The skin was then excised on this side,exposing the nasal SMAS. Next, the nasal SMAS was incised inthe midline, allowing sub-SMAS dissection from the midlinelaterally. Eventually, a subperichondral dissection was per-formed. The opposite side in 9 specimens was left intact untilthe end of the procedure. Then the lateral wall of this un-

touched side was resected to perform the histologic examina-tion. In 1 specimen, the sub-SMAS dissection of the left sidewas performed to show the correlation between the histologicand anatomical findings.

2. In 10 specimens, subcutaneous and sub-SMAS dissec-tions were performed using a cranio-caudal approach throughthe glabellar cutaneous incision; in another 10 specimens, theprocedure wasperformed from thecolumellato radix. A trans-columellar incision and a rim incision were used, and subder-mal dissection was performed. This anatomical approach dif-fers from the surgical external rhinoplasty approach, whichinterrupts the subcutaneous layer that lies between the skin andthe anterior border of the medial crura. This approach trans-acts the small arteriesrunning in the columella before the sub-

SMAS dissection is performed.

HISTOLOGIC ANALYSIS

Histologic examination of 9 specimens excised from the left lat-eral nasal wall (from the medial canthus to the nostril rim), in-cluding layers of this area, wasperformed. The tissues were im-mediately fixed in 10% formalin. After decalcification in 5%chlorhydric acid, the specimens were embedded in paraffin, andMasson trichrome stain was used. Microsections of the speci-mens were performed, then the sections were observed underlight microscopy.

RESULTS

CADAVER DISSECTION

Incision in the Midline

Subdermal Dissection. A continuous musculo-aponeu-rotic layer, which connected the nasal muscles to thefacialSMAS, was exposed. It covered the whole nose,fromthe radix to the nostril rim, and continued medially onthe columella. At this level, it was superficial to the cau-dal border of the medial crura of the lower lateral carti-

Figure 1. Right lateral view. The superficial aspect of the nasal superficialmusculoaponeurotic system: the nasal muscles (black arrow, the procerus;blue arrow, the levator labii alaeque nasi muscle and the orbicularis oculimuscle; red arrow, tranverse nasalis muscle. All of these muscles are linkedby the nasal aponeurosis.

Figure 2. Basal view of the superficial medial layer of the nasal superficialmusculoaponeurotic system. This layer is penetrated by vascular elementslying immediately beneath the dermis (black arrow).










lage (LLC), and it met the depressor septi nasi muscle just anterior to the anterior nasal spine (Figure 1 andFigure 2).

The subcutaneous layer was easily undermined fromthe nasal SMAS layer. Only subcutaneous fat was no-ticed in this plane, and it was more abundant in the supra–nasal tip area, as presented in widely accepted anatomi-cal and surgical descriptions.

Blunt dissection between the dermis and the musculo-aponeurotic layer was impossible in the area of the dilatornasi muscle, andit was necessary to use a sharp scalpeldis-section to separate these anatomical structures. Fibers of the dilator naris muscle intermingle with the SMAS fibersat the level of the junction of these 2 structures.

Sub-SMAS Dissection. Incision of the nasal SMAS in themidline was performed in 10 specimens, and the nasalSMAS was undermined (in 5 specimens on the right side,in the other 5 on the left side) from the bony and carti-laginous framework. Then the nasal SMAS was re-flected laterally (Figure 3, black arrow).

The nasal SMAS appears as a unique anatomicallayer that is easily dissected (Figure 4). It seems tohave an insertion, composed of yellowish tissue differ-ent from the reddish muscular layer, onto the nasal

skeleton at the level of the internal nasal valve

(Figure 3, red arrow). This different tissue seems to beanother, deeper anatomical layer that connects the na-sal SMAS to the internal nasal valve.

According to these anatomical observations, later-ally, at thelevel of the internal nasal valve, the nasal SMASseems to be composed of 2 layers:

1. A superficial layer that continues from the dorsalportion of thenasal SMAS, which is composed of thetrans-verse nasalis muscle. This layer passes over the LLC, andit inserts into the skin of the alar margin. Here, it is verythin and difficult to dissect, and it may be called the su-perficial lateral layer (or supra-alar layer) of the nasalSMAS (Figure 3, blue arrow);

2. A deep yellowish layer that originates from the na-

sal SMAS at the level of the internal nasal valve and in-serts into this valve. This layer may be called the deeplateral layer (or valve layer) of the nasal SMAS (Figure 3,red arrow).

According to these findings, laterally, the nasal SMASseems also to be divided into a cranial portion that ex-tends from the frontalis muscle to the internal nasal valveand can be easily dissected and a caudal portion that over-lies the LLC and includes superficial and inconstantmuscles surrounding the LLC. This part is very thin anddifficult to dissect.

Figure 3. Upper nasal superficial musculoaponeurotic system (SMAS).The nasal SMAS before its division (black arrow); note its insertion into theinternal nasal valve, which appears yellowish (red arrow). The medialsuperficial layer covers the lower lateral cartilage (blue arrow) and inserts onto the skin of the alar margin.

Figure 4. Deep aspect of nasal superficial musculoaponeurotic system(SMAS) after sub-SMAS dissection and separation of SMAS insertions atthe level of the internal nasal valve (black arrow) and the margin of thenostrils (red arrow).










In the same way, medially, at the level of the inter-nal nasal valve, the nasal SMAS seems to divide into asuperficial and a deep layer. The deep medial layerruns between the anterior septal angle and the inter-domal ligament. It runs in the membranous septum,between the caudal border of the septum and themedial crura of the LLC, toward the anterior nasalspine (Figure 5 and Figure 6). This anatomicalstructure could correspond to the ligament describedby Pitanguy.4 In fact, it is described as a mediallylocated structure, originating in the fascia of the upper

third of the nose, which extends down to the domalsegment of the middle crus, merging below the infero-anterior portion of the septum.4

The superficial medial layer runs caudally superficialto the caudal border of the medial crura of the alar car-tilages to reach and interconnect with some fibers of thedepressor septi nasi muscle9 (Figure 7).

Subperichondral Dissection.On the right side ofthe samespecimen, subperichondral dissection was performedafter the subcutaneous and sub-SMAS dissections(Figure 8). The perichondrium (periosteum) was el-evated and raised with 2 forceps. In this plane, the dis-section stopped at the internal nasal valve according tothe fusion of the perichondral tissue of the upper lateralcartilage (ULC) and the LLC. There was no evidence of any fibrous tissue running between the cranial marginof the LLC and the caudal margin of the ULC. In fact,the cartilages seemed to be almost continuous.

Cranio-Caudal Dissection

Sub-SMAS Dissection. Subdermal dissectionfollowed bycutaneous excision of the nasal pyramids of 10 speci-mens was performed, so that complete exposure of thenasal SMAS was obtained. Then, the nasal SMAS was in-cised at the level of the radix of the nose and laterallytoward the medial canthus. The sub-SMAS dissection wasperformed, and there was evidence that

1. Laterally the dissection could be performed in thesame surgical plane up to the internal nasal valve.

2. Medially, the nasal SMAS was easily elevated up to

the anterior septal angle without cutting any anatomicalstructure. At this point, it was not possible to reach thedomes directly owing to the presence of vertical anatomi-cal structures. Two planes became apparent: a deep planeand a superficial plane. The dissection in the deep planewas simply performed following the deep aspect of thena-sal SMAS anterior to the septum, without cutting it. Thisdissection led directly to the nasal spine. To dissect to-ward the domes of the LLC, it was necessary to cut the na-salSMASlayer that runs caudally to theanterior septalangle(whatweconsider thedeepmedial layer ofthenasalSMAS).

Figure 5. Interdomal ligament. The domes of the alar cartilages are joined bya fibroaponeurotic structure, the interdomal ligament (black arrow).

Figure 6. The interdomal ligament (red arrow) separates the deep andsuperficial medial layers of the nasal superficial musculoaponeurotic system.The deep medial layer (black arrow) runs immediately anterior to the anteriorseptal angle and cranial to the interdomal ligament. The superficial mediallayer runs into the columella in the subdermal plane.

Figure 7. Right lateral view. Superficial medial layer of the nasal superficialmusculoaponeurotic system running into the columella. Note the columellararteries (black arrow) and the relationship between this layer and the fibersof the depressor septi nasi muscle (red arrow).










The sub-SMAS nasal dissection through cranio-caudal approach shows that the nasal SMAS layer is di-vided at the level of the internal nasal valve into super-ficial and deep layers. These layers contain vessels.

Columellar Incision and Cranial Dissection. Ten nasalsub-SMAS dissections were performed using columellarand rim incisions. In 5 specimens, both the subcutane-ous and the sub-SMAS dissections were performed to iso-late the nasal SMAS layer. The cutaneous incision wasplaced in the labiocolumellar junction, and the dissec-tion was performed in the subdermal plane over the LLCand cranially to the radix. The incision of the subcuta-neous tissue between the dermis and the cartilages wasperformed just above the cartilaginous structures, as inthe open approach. The dissection could be performedup to the anterior nasal septal angle where vertical fi-brous bands were noticed, which passed immediately an-terior to theanterior septal angle. As described in thepre-

vious subsection, 2 planes became apparent: a deep planeand a superficial plane. The dissection in the deep planewas performed following the layer that originates fromthe nasal SMAS, without cutting it. This dissection di-rectly led to the nasal spine. The dissection in the super-ficial plane was possible only after cutting the layer asdescribed (which also contains blood vessels), and it al-lowed us to reach the dorsum. Laterally at the level of the cranial border of the LLC, it was not possible to con-tinue the dissection. To reach the radix, it was neces-sary to cut or to elevate the yellowish tissue, which in-serted onto the internal nasal valve.

In another 5 specimens, only the sub-SMAS dissec-tion in the deep areolar plane, superficial to the peri-

chondral plane, was performed using the transcolumel-lar incision. The same anatomical planes becameapparent.

HISTOLOGIC ANALYSIS

The histologic examination (Figure 9) of the speci-mens of the left lateral nasal wall showed the presenceof a fatty componentbetweentheULC andthe LLC. Therewas no evidence of anyfibrous anatomical structure run-ning between these 2 cartilaginous components. Only the

perichondrium of the ULC seemed to be in continuitywith that of the LLC.

COMMENT

CADAVER DISSECTION

Thecadaverdissectionshowedtheexistenceofauniqueandcontinuous anatomicallayer,thenasal SMAS, consisting of the nasal muscles.These musclesare the transverse nasalismuscle, the procerus, andthe compressor naris major andminor. Regarding the levator labii alaeque nasi and the di-latornasimuscles,thediscussionisstillopen,andouropin-ion is that these muscles connect the nasal SMAS to the fa-cial SMAS.Thiswholestructure overliesthenasal bony andcartilaginous framework and continues from the “frontalSMAS” that consists of thefrontalismuscle in this area as auniquelayer.Attheleveloftheinternalnasalvalve,itseems

todivideinto a superficiallayer anda deep layer. Each layercan be divided into medial and lateral expansion.The superficial layer of the nasal SMAS passes super-

ficially over the LLC: laterally, it inserts into the skin of the alar margins, and medially, it joins the depressor septinasi muscle at the nasolabial angle (Figure 10).

The deep layer of the nasal SMAS runs deep to the su-perficial layer; laterally, it insertsintotheinternalnasal valvewith a fatty component; medially,it passesimmediately an-terior to the anterior septal angle, and it runs posterior totheinterdomal ligamentof thealar cartilages. Thus, thein-

Figure 8. Subperichondral (periosteal) dissection. Note the zones ofadherence of the perichondrium of the upper lateral cartilage into the internalnasal valve (black arrow).

A B

Figure 9. Overview of the nasal superficial musculoaponeurotic system(SMAS) compared with the histologic section. A, Histologic findings on

vertical cross section of the lateral wall of the nose. The upper lateralcartilage and lower lateral cartilage are colored in dark blue and are verticalstructures; the external and vestibular skin is in continuity; the Y-shapedempty structure corresponds to the dorsal nasal vein. Red arrows indicatethe correspondence between the yellowish anatomical component, belongingto the nasal SMAS, and the fatty tissue (Masson trichrome, originalmagnification10). B, Anatomical sub-SMAS dissection showing theinsertion of the nasal SMAS in the nasal valve; note the correspondence withhistological findings in the nasal valve area. The black line indicates thevertical cross section used for microscopic histologic studies.










terdomal ligament separates the deep and the superficialmedial expansions of the nasal SMAS. The dermocartilagi-

nous ligament described by Pitanguy4

corresponds, in ouropinion, to the deep medial expansion. There is no evi-dence of any fibrous structure originating from the der-mis and crossing the nasal SMAS. Basing our statementson anatomical and surgicalobservations, the section of themedial deep expansion of the nasal SMAS determines na-saltip rotationandimprovementin nasal tipdefinition.Thesame result was described by Pitanguy4 when the inter-ruption of the dermocartilaginous ligament was per-formed. It is important to stress the fact that Pitanguy etal10 asserted thatthe dermocartilaginousligament waspre-dominantly observedin patients withplatyrrhine and bul-bous noses; on the contrary, in our study, only specimensof white individuals were examined. Furthermore, Pitan-

guy4

hypothesized that the fibers of the dermocartilagi-nous ligament could represent the vestigial remnants of,or an evolutionary link to, the transverse nasalis muscle.Our results also suggest a close relationshipbetween these2 anatomical structures.

Clinical observations and routine surgical practiceshow that from a surgical point of view, these anatomi-cal findings may have an impact on surgical procedures,but this statement needs to be better assessed by objec-tivemeasurements, which will be provided in further stud-ies. Both the deep and the superficial medial layers of the

nasal SMAS may be considered to be the lowering liga-ments of the nasal tip. Surgical section of these anatomi-cal structures is performed routinely during the exter-nal rhinoplasty approach, and clinical evidence showsnasal tip rotation after section of these ligaments.

HISTOLOGIC ANALYSIS

The histologic examination (Figure 9) of the lateral na-sal wall showed that the portion of the nasal SMAS thatlies over the ULC (transverse nasalis muscle) is in con-tinuity, at the level of the nasal valve, with a fatty com-

ponent that corresponds to the yellowish expansionnoted during the cadaver dissections. There was no evi-dence of any fibrous structures between the ULC andLLC, and only the perichondrium joining ULC to LLCwas noticed.

CONCLUSIONS

In this study, we have demonstrated that it is possibleand reliable to propose a unique and complete anatomi-cal vision of the nasal SMAS. The nasal SMAS continuesfrom the frontalis muscle, which may be called the fron-tal SMAS, and at the level of the internal nasal valve it

divides into a deep anda superficial layer; each layer con-sists of lateral and medial layers. This unified vision of the nasal SMAS may explain the connections between allthe muscular andligamentous components that were pre-viously described by other authors. It seems to corre-spond to anatomical findings observed during surgicalprocedures, such as fatty expansions onto the internalnasal valve and vertical fibrous bands caudal to the an-terior septal angle (Figure 11).

The dermocartilaginous ligament described byPitanguy4 corresponds, in our opinion, to the deep me-

Figure 10. Superficial medial layer of the nasal superficialmusculoaponeurotic system (SMAS). Note that this layer continues from thedivision of the nasal SMAS into deep and superficial layers.

Figure 11. Drawing of the anatomical structures analyzed herein (the lowerlateral cartilage has been interrupted to show the structures that lie beneath).Superficial lateral layer (black arrow); superficial medial layer (red arrow);

deep medial layer (blue arrow).










dial layer of the nasal SMAS. The resection of this ana-tomical structure determines the same change to the na-sal tip and supra–nasal tip area of the nose as describedby Pitanguy.4

Accepted for Publication: September 10, 2007.Correspondence: Yves Saban, MD, PhD, Departmentsof Ear, Nose, and Throat and Facial Plastic Surgery, Cli-nique St Antoine, Nice 06000, France (yves.saban

@wanadoo.fr).Author Contributions: Study concept and design: Saban,Amodeo, Hammou, andPolselli. Acquisition of data: Saban,Amodeo, Hammou, and Polselli. Analysis and interpre-tation of data: Saban, Amodeo, Hammou, and Polselli.Drafting of the manuscript: Saban, Amodeo, Hammou, andPolselli. Critical revision of the manuscript for importantintellectualcontent:Saban, Amodeo, Hammou, andPolselli. Administrative, technical, and material support: Saban,Amodeo, Hammou, and Polselli. Studysupervision: Saban,Amodeo, Hammou, and Polselli.Financial Disclosure: None reported.

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An Anatomical Study of the Nasal Superficial Musculoaponeurotic System

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