Special Topic Facial Arterial Depth and Relationship with the Facial Musculature Layer Jae-Gi Lee, Ph.D. Hun-Mu Yang, D.D.S., Ph.D. You-Jin Choi, B.S., B.S.D.H. Vittorio Favero, M.D. Yi-Suk Kim, M.D., Ph.D. Kyung-Seok Hu, D.D.S., Ph.D. Hee-Jin Kim, D.D.S., Ph.D. Cheonan and Seoul, Republic of Korea; and Verona, Italy
Background: Previous studies have revealed a variation in the origin and distribution patterns of the facial artery. However, the relationship between the facial artery and the facial muscles has not been well described. The purpose of this study was to determine the facial artery depth and relationship with the facial musculature layer, which represents critical information for dermal filler injection and oral and maxillofacial surgery. Methods: Fifty-four embalmed adult faces from Korean cadavers (36 male and 18 female cadavers; mean age, 73.3 years) were used in this study. A detailed dissection was performed, with great care being taken to avoid damaging the facial artery underlying the facial skin and muscle. Results: The facial artery was first categorized according to the patterns of its final arterial branches. The branching pattern was classified simply into three types: type I, nasolabial pattern (51.8 percent); type II, nasolabial pattern with an infraorbital trunk (29.6 percent); and type III, forehead pattern (18.6 percent). Each type was further subdivided according to the facial artery depth and relationship with the facial musculature layer as types Ia (37.0 percent), Ib (14.8 percent), IIa (16.7 percent), IIb (12.9 percent), IIIa (16.7 percent), and IIIb (1.9 percent). Conclusion: This study provides new anatomical insight into the relationships between the facial artery branches and the facial muscles, including providing useful information for clinical applications in the fields of oral and maxillofacial surgery. (Plast. Reconstr. Surg. 135: 437, 2015.)
I
njectable filler treatments such as dermal filler injection have the advantages of being relatively noninvasive and simple; however, their use has been challenged by the menace of vascular complications.1–5 In particular, the direct impingement of a needle may result in numerous vascular complications, ranging from slight bruising to blindness, which is the most feared complication. Consideration of the course of the facial artery and application of a cannula with a blunt tip might almost guarantee a safe manipulation.6 From the Department of Dental Hygiene, School of Health and Medicine, Namseoul University; the Department of Anatomy, College of Medicine, Dankook University; the Division of Anatomy and Developmental Biology, Department of Oral Biology, Human Identification Research Center, BK21 PLUS Project, Yonsei University College of Dentistry; the Section of Dentistry and Maxillofacial Surgery, Department of Surgery, University of Verona; and the Department of Anatomy, Ewha Womans University School of Medicine. Received for publication February 8, 2014; accepted August 1, 2014. The first two authors contributed equally to this work. Copyright © 2015 by the American Society of Plastic Surgeons DOI: 10.1097/PRS.0000000000000991
However, given that use of a blunt tip and aspiration after placement of the needle or cannula cannot prevent vessel compression, this longestablished recommendation for avoiding direct injury appears to be insufficient to prevent vascular accidents by extravascular compression.7,8 The filler materials could be placed within the subcutaneous tissue or between the muscle fibers, or even injected into the space between the periosteum and the muscles. Clinically, the physician can manipulate the subcutaneous layer into which the instrument is placed by pinching the skin to allow targeting of subcutaneous injections, or by recognizing when bone contact has occurred for deep filler injections. With dermal filler injection in particular, selection of the proper injection layer is imperative for aesthetic considerations, to ensure provision of the proper volume, and to prevent numbness and the diffusion of fillers from the injection space. Therefore, knowledge of the relationship between the facial artery and Disclosure: The authors have no financial interest to declare in relation to the content of this article.
www.PRSJournal.com
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Plastic and Reconstructive Surgery • February 2015 its neighboring structures in the various subcutaneous layers is necessary to enable selection of the most appropriate space and passage of the filler materials to prevent iatrogenic injury by intravascular or extravascular accident. Unfortunately, the descriptions of facial artery anatomy published to date lack the details of not only its course and ramifying patterns (and possible variations thereof) but also its relationships in the various subcutaneous layers. More definitive data are required than the currently available ambiguous description of the facial artery presenting a tortuous course from the premasseteric area to the angular area for safe manipulation during injectable treatments. The aim of the present study was to elucidate the details of the course of the facial artery in the various subcutaneous layers, and to shed light on how the facial artery proceeds within the neighboring tissues by means of detailed and careful dissection.
MATERIALS AND METHODS Dissection of the Facial Artery and the Facial Muscles Fifty-four embalmed adult faces from Korean cadavers (36 male and 18 female cadavers; mean age, 73.3 years) were used in this study. All cadaveric objects in this study were legally donated to Yonsei Medical Center. The skin and subcutaneous tissue were carefully removed by detailed dissection, preserving the facial artery branches and their courses on the surface of the facial muscles, with great care being taken to avoid causing any damage. The course of the facial artery branches on the surface of each facial muscle was then recorded, sketched, and photographed. The facial artery was sketched by tracking it from the inferior border of the mandible to its terminal branches, and by cutting and retracting the facial muscles without damaging the facial artery branches to reveal its course. Classification of the Facial Artery According to the Terminal Branch and in Relation to the Facial Muscle The major facial artery branches were divided into the inferior labial artery, superior labial artery, inferior alar artery, angular artery, and lateral nasal artery according to their course, location, and distribution areas. In this study, the facial artery was classified into three types on the basis of the general artery classification according to the anatomical pattern of each facial artery terminal branch. Facial arteries running toward the nasion
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without forming angular artery and with branches around the lips and nose were classified as type I (nasolabial pattern). In type I, the facial artery ended as the lateral nasal artery (Fig. 1, above). Those running in the same direction as type I but forming nasolabial and infraorbital trunks were classified as type II (nasolabial pattern with an infraorbital trunk). The nasolabial trunk originated from the facial artery near the cheilion after branching off from the inferior labial artery, and then proceeded toward the upper lip, the nasal septum, and the lateral side of the nose next to the nasal ala. The infraorbital trunk was defined as the vertically independent and separate arterial branch from the facial artery that ran a deviated course toward the infraorbital and nasojugal area (Fig. 1, center). The nasolabial trunk bifurcates into the superior labial artery, inferior alar artery, and lateral nasal artery, whereas the infraorbital trunk runs inferiorly toward the orbital region and forms the angular artery. In type III (forehead pattern), the terminal branch of the facial artery ended as an angular artery, an anastomotic branch with the dorsal nasal artery (Fig. 1, below). In addition, the facial artery branches of all specimens passed either over or beneath the facial muscles in the perioral and infraorbital regions. Therefore, each facial artery type (i.e., type I to III) was further subdivided according to its depth and its relationship to the facial musculature layer (a and b) (Fig. 1).
RESULTS Location of the Facial Artery Branches Relative to the Facial Muscles Type I (a and b; nasolabial pattern) was observed in 51.8 percent (28 of 54) of cases (Fig. 1, above), with type Ia being the most frequent [20 of 54 (37.0 percent)]. In the lower lip, the facial artery was covered by the platysma and the depressor anguli oris, and gave off a branch of the inferior labial artery deep to the depressor labii inferioris. At the lateral modiolar region, the facial artery was located anterior to the buccal fat pad between the risorius and the zygomaticus major. Superior to the mouth corner, the inferior labial artery and superior labial artery divided from the facial artery, superficial to the orbicularis oris, before reaching the vermilion border of the upper and lower lips. The facial artery then ascended deep to the levator labii superioris and levator labii superioris alaeque nasi. At the nasal alar region, the inferior alar artery and lateral nasal artery supplying the
Volume 135, Number 2 • Facial Artery and Facial Muscle columella and the nose tip ramified from the facial artery deep to the levator labii superioris and the zygomaticus minor (Fig. 2). In type Ib [eight of 54 (14.8 percent)], all facial artery branches were located deep to facial muscles. Type II (a and b; nasolabial pattern with an infraorbital trunk) was observed in 16 of 54 cases (29.6 percent) (Fig. 1, center). In type IIa [nine of 54 (16.7 percent)], the nasolabial trunk ran similarly to type Ib, covered by the facial muscles. However, the infraorbital trunk ran toward the infraorbital area, superficial to the zygomaticus major and deep to the zygomaticus minor. It then turned medially toward the nasojugal area along the lower border of the orbicularis oculi and superficial to the levator labii superioris and levator labii superioris alaeque nasi, and ended as the angular artery. In type IIb [seven of 54 (12.9 percent)], the nasolabial trunk ran similarly to type Ia, and the infraorbital trunk was superficial to the zygomaticus major, zygomaticus minor, and levator labii superioris in the infraorbital and nasojugal areas (Fig. 3). Type III (forehead pattern) was identified in 10 of 54 cases (18.6 percent), and ended as the angular artery (Fig. 1, below). During its course, the type IIIa facial artery [nine of 54 (16.7 percent)] was not covered by the facial muscles at the upper lip, lateral to the margin of the orbicularis oris (nasolabial fold), and at the lateral area of the dorsum of nose (angular region) (Fig. 4). Type IIIb was found in one case (1.9 percent), in which the deep facial artery trunk ran through the infraorbital area located beside the main trunk of facial artery branches shown for type IIIa. This additional arterial trunk, which coursed deep to the facial muscles, joined with the branches of the infraorbital artery and ran toward the lateral side of the nose.
DISCUSSION Clinical knowledge of facial artery anatomy, including its depth, is required when performing facial dermal filler injection, rather than simply its location or the distribution of its branches. Although there are many reports on the classification of the facial artery branches and their distribution in the facial region, very few studies have explored their depth.9–14 Ultrasonography provides accurate information regarding the location of the facial arteries in individual patients, but one disadvantage of this tool is that it is difficult to detect small dermal vessels or to confirm their relationships with the facial muscles. The prevalence of complications caused
by serious skin necrosis has recently been reduced as a result of the use of a blunt cannula instead of a sharp needle. However, the side effects of injecting filler materials into subcutaneous tissues remain an issue because of the lack of anatomical knowledge regarding the relationship between the depth of the facial artery and the facial musculature layer.4,6 General anatomy textbooks report that the facial artery proceeds toward the oral commissure and ascends along the lateral side of the nose15; this description reflects the type I (51.8 percent, nasolabial pattern) or the type III (18.6 percent, forehead pattern) patterns described in the present study. Because types I and III (71.4 percent) were observed more frequently than type II (29.6 percent) in this study, besides the general description of the courses of facial artery, patterns identical to a type II facial artery were also observed (Fig. 1). In particular, the type II pattern (29.6 percent, nasolabial pattern with an infraorbital trunk) should be considered, where the infraorbital trunk is located superficial to the zygomaticus major and levator labii superioris. There are also rare reports of a type II pattern, with the additional facial artery trunk running in the infraorbital and nasojugal areas.10,12,16 Physicians should take care to consider the facial muscle and the facial artery when they inject soft-tissue fillers into this region because bruising or vascular accidents resulting from extravascular compression occasionally occur in the skin during dermal filler injection (Figs. 1, center, and 3). Future studies should investigate more specimens and consider the possibility of racial differences in the course of the facial artery. However, it can already be speculated from the present findings that knowledge of the coursing pattern of the infraorbital trunk in the type II facial artery is important for a complete understanding of the distribution of the facial artery in the face. The facial artery branches were located in the subcutaneous layer in the superomedial region of the mouth corner (between the cheilion and the nasal ala) and on the surface of the facial muscle in 85.2 percent of cases (46 of 54). In particular, erythema, bruising, and superficial skin necrosis are quite likely to occur during filler injection into this region because the facial artery branches are located immediately below the facial skin. Therefore, special attention should be paid when injecting fillers into this region. Koh et al. reported that the facial artery proceeded upward in the vicinity of the nasolabial fold in 88 percent.10 Yang et al. reported that the facial artery proceeded along the nasolabial fold in 93.3
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Fig. 1. The three patterns of the facial artery (FA) encountered in this study, with illustrations of the course of the facial artery relative to the facial muscles. Each type was subdivided according to the location of the
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Volume 135, Number 2 • Facial Artery and Facial Muscle
Fig. 2. Photographs and illustration showing type Ia (nasolabial pattern) based on the courses of facial arterial branches and facial muscles. Facial skin and subcutaneous tissue were eliminated without damaging the facial arterial branches. (Left) Arrowheads indicate the facial arterial branches superficial to the facial muscle. (Center) The facial muscles were cut and retracted to allow observation of the facial artery branches traveling deep into them. Facial artery branches: IA, inferior alar artery; IL, inferior labial artery; LN, lateral nasal artery; and SL, superior labial artery. Facial muscles: DAO, depressor anguli oris; DLI, depressor labii inferioris; LAO, levator anguli oris; LLS, levator labii superioris; LLSAN, levator labii superioris alaeque nasi; OOc, orbicularis oculi; OOr, orbicularis oris; Pl, platysma; Ri, risorius; Zmi, zygomaticus minor; and ZMj, zygomaticus major.
percent and the artery was located within 5 mm of the fold in 42.9 percent.17 They mentioned also that the facial artery crossed the nasolabial fold in 33.9 percent, and reported a case where the facial artery was located within the muscle fibers
Fig. 1. (Continued) facial artery relative to the facial musculature layer. To help distinguish between the superficial and deep courses of the facial artery, the color of the facial artery coursing beneath the facial muscles is lighter than its superficial course, which runs on top of the facial muscles. (Above) Type I, nasolabial pattern. (Center) Type II, nasolabial pattern with an infraorbital trunk; purple and pink colors of the facial artery branches (FAb) indicate the nasal and infraorbital trunks, respectively. (Below) Type III, forehead pattern. Facial artery branches: Ag, angular artery; DFAt, deep FA trunk; IA, inferior alar artery; IL, inferior labial artery; IO, infraorbital artery; LN, lateral nasal artery; and SL, superior labial artery. Facial muscles: DAO, depressor anguli oris; DLI, depressor labii inferioris; LAO, levator anguli oris; LLS, levator labii superioris; LLSAN, levator labii superioris alaeque nasi; OOc, orbicularis oculi; OOr, orbicularis oris; Pl, platysma; Ri, risorius; Zmi, zygomaticus minor; and Zmj, zygomaticus major.
reaching the skin of the fold. Thus, the area near the nasolabial fold would be susceptible to vascular injury during injectable treatment. Considering the diversity and unpredictability of depth of the arterial location in the present study, it can be speculated that aspiration before injection into the nasolabial fold should be performed regardless of the depth of injection. The nasolabial region is a donor area for local skin flaps (skin, mucosal, and musculomucosal flaps). This region has a rich supply of blood through the facial artery branches.14,18 Based on the present findings, the inferior labial artery, which is distributed close to the lower lip, is located deeper than the depressor anguli oris and the depressor labii inferioris in most cases; however, the location of the superior labial artery varies widely, and includes cases where the superior labial artery penetrates through the orbicularis oris to run along the surface and then into the deep region. In other cases, it runs in the deep region of the orbicularis oris and then penetrates through it to emerge at the site of the nasal tip to
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Fig. 3. Photograph and illustration showing type IIb (nasolabial pattern with an infraorbital trunk). A deeper dissection was performed in which the facial muscles were cut and retracted while preserving the facial artery (FA). The yellow arrowheads indicate the facial artery branches of the subcutaneous layer between the facial skin and the facial muscles. The illustration shows the facial artery depth relative to the facial muscles. Facial artery branches: Ag, angular artery; IA, inferior alar artery; IL, inferior labial artery; LN, lateral nasal artery; and SL, superior labial artery. Facial muscles: DAO, depressor anguli oris; DLI, depressor labii inferioris; LAO, levator anguli oris; LLS, levator labii superioris; LLSAN, levator labii superioris alaeque nasi; OOc, orbicularis oculi; OOr, orbicularis oris; Pl, platysma; Ri, risorius; Zmi, zygomaticus minor; and ZMj, zygomaticus major.
form septal branches. Therefore, the information on the course and location of the facial artery presented in this study would be helpful to physicians during flap surgery. The angular artery is known to be vulnerable to iatrogenic injury during dermal filler injection in the sellion area and the dorsum of the nose. The frequency of angular artery ramification from the facial artery has been variously reported as 72 percent, 68 percent, 40.7 percent, 22 percent, and 4 percent, by Nakajima et al., Niranjan, Koh et al., Pinar et al., and Mitz et al., respectively.10,12–14,19 An angular artery was observed in 48.2 percent of the present cases (types II and III) (Figs. 3 and 4). Areas with an insufficient blood supply from the facial artery are supplied by the branches of the maxillary or internal carotid artery.13,20 A supplementary artery derived from the ophthalmic artery was shown to supply the angular area in the case
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where the facial artery lacked an angular artery.20 Because the ophthalmic artery was also distributed superficial to the facial expression muscles in some parts of the forehead, superficial injection of dermal filler to the angular area should be performed meticulously and with great caution, regardless of the origin of the angular artery. Lazzeri et al. reported cases of blindness following arterial impingement during dermal filler injection, and recommended various technical tips to reduce the risk of vascular accidents. In their report, small-tipped needles and cannulae were recommended because of their slow injection speed and thus reduced possibility of causing vascular occlusion.21 However, the physician needs to know the precise anatomy of arterial distribution in the treated area before performing surgical protocols. Knowledge of the possible courses of the facial artery without consideration of the
Volume 135, Number 2 • Facial Artery and Facial Muscle
Fig. 4. Photograph and illustration showing type IIIa (forehead pattern). Yellow arrowheads indicate the facial arterial branches in the subcutaneous tissue. The illustration shows the facial artery (FA) depth relative to the facial muscles. Facial artery branches: Ag, angular artery; IA, inferior alar artery; IL, inferior labial artery; LN, lateral nasal artery; SL, superior labial artery. Facial muscles: DAO, depressor anguli oris; DLI, depressor labii inferioris; LAO, levator anguli oris; LLS, levator labii superioris; LLSAN, levator labii superioris alaeque nasi; OOc, orbicularis oculi; OOr, orbicularis oris; Pl, platysma; Ri, risorius; Zmi, zygomaticus minor; and ZMj, zygomaticus major.
muscle layer is not adequate for injectable treatment to the face. Feinendegen et al. reported that dermal filler injection to the nasolabial fold using a 2-mm-diameter cannula resulted in global aphasia and mild sensorimotor hemiparesis on the right side; a radiologic examination revealed that the temporoparietal area of the left middle cerebral artery was infarcted.22 Based on that case, the use of a blunt injector tip does not seem to be able to completely prevent placement of the injectable in cases of limited knowledge of the ambiguous description of the facial artery running from the premasseteric notch to the nasion through the nasolabial fold. Despite the variations in the facial artery course described in this article, it has been demonstrated that facial artery branches on the nasolabial fold, inferolateral area to the mouth corner, and area lateral to the ala are frequently positioned subcutaneously. These areas are often manipulated during dermal filler injection for esthetic purposes. Therefore, the subcutaneous injection of dermal
filler materials—including hyaluronic acid and autogenous adipose tissues—to the nasolabial fold would carry with it a high risk of vascular damage.
CONCLUSIONS In this study, the course of the facial artery is classified into three types, the details of which are observed separately, according to the locations of the facial artery branches as they coursed either along the surface or in the deep regions of the facial muscles. The results of this study suggest that constant movement of the needle tip helps to avoid intravascular injection into arteries located in the subcutaneous tissues and reduces the likelihood of the side effect of arterial compression, particularly during facial dermal filler injection. Hee-Jin Kim, D.D.S., Ph.D. Department of Oral Biology, Room 601 Yonsei University College of Dentistry 50 Yonsei-Ro Seodaemun-Gu, Seoul 120-752, Republic of Korea [email protected]
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Plastic and Reconstructive Surgery • February 2015 acknowledgments
This work was supported by the National Research Foundation of Korea grant funded by the Korea government (Ministry of Education, Science & Technology) (no. 2011-0007612). We thank Sang-Hoon Kwon at New York University College of Arts and Science and SoYeon Kim at Georgetown University, College of Arts and Science, for assistance in revising the article and anatomical procedure. All authors were well-informed of the World Medical Association Declaration of Helsinki, Ethical Principles for Medical Research involving Human Subjects, and confirmed that the present study firmly fulfilled the declaration. None of the authors has financial or private relationships with commercial, academic, or political organizations or people that could have improperly influenced this research. All cadaveric objects in this study were legally donated Yonsei Medical Center. REFERENCES 1. Newman J. Review of soft tissue augmentation in the face. Clin Cosmet Investig Dermatol. 2009;2:141–150. 2. Ozturk CN, Li Y, Tung R, Parker L, Piliang MP, Zins JE. Complications following injection of soft-tissue fillers. Aesthet Surg J. 2013;33:862–877. 3. Daines SM, Williams EF. Complications associated with injectable soft-tissue fillers: A 5-year retrospective review. JAMA Facial Plast Surg. 2013;15:226–231. 4. Cohen JL. Understanding, avoiding, and managing dermal filler complications. Dermatol Surg. 2008;34(Suppl 1):S92–S99. 5. Grunebaum LD, Bogdan Allemann I, Dayan S, Mandy S, Baumann L. The risk of alar necrosis associated with dermal filler injection. Dermatol Surg. 2009;35(Suppl 2):1635–1640. 6. Fulton J, Caperton C, Weinkle S, Dewandre L. Filler injections with the blunt-tip microcannula. J Drugs Dermatol. 2012;11:1098–1103. 7. Park TH, Seo SW, Kim JK, Chang CH. Clinical experience with hyaluronic acid-filler complications. J Plast Reconstr Aesthet Surg. 2011;64:892–896. 8. Shumaker PR, Sakas EL, Swann MH, Greenway HT Jr. Calcium hydroxylapatite tissue filler discovered 6 years
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after implantation into the nasolabial fold: Case report and review. Dermatol Surg. 2009;35(Suppl 1):375–379. 9. Aratani R. Anatomical Study of the External Carotid Artery of Japanese: Facial Artery (dissertation). Tokyo: Tokyo Dental College; 1960. 10. Koh KS, Kim HJ, Oh CS, Chung IH. Branching patterns and symmetry of the course of the facial artery in Koreans. Int J Oral Maxillofac Surg. 2003;32:414–418. 11. Lohn JW, Penn JW, Norton J, Butler PE. The course and variation of the facial artery and vein: Implications for facial transplantation and facial surgery. Ann Plast Surg. 2011;67:184–188. 12. Pinar YA, Bilge O, Govsa F. Anatomic study of the blood supply of perioral region. Clin Anat. 2005;18:330–339. 13. Mitz V, Ricbourg B, Lassau JP. Facial branches of the facial artery in adults: Typology, variations and respective cutaneous areas (in French). Ann Chir Plast. 1973;18:339–350. 14. Niranjan NS. An anatomical study of the facial artery. Ann Plast Surg. 1988;21:14–22. 15. Standring S. Gray’s Anatomy: The Anatomical Basis of Clinical Practice. Edinburgh: Elsevier/Churchill Livingstone; 2008. 16. Furukawa M, Mathes DW, Anzai Y. Evaluation of the facial artery on computed tomographic angiography using 64-slice multidetector computed tomography: Implications for facial reconstruction in plastic surgery. Plast Reconstr Surg. 2013;131:526–535. 17. Yang HM, Lee JG, Hu KS, et al. New anatomical insights on the course and branching patterns of the facial artery: Clinical implications of injectable treatments to the nasolabial fold and nasojugal groove. Plast Reconstr Surg. 2014;133:1077–1082. 18. Turan A, Kostakoglu N, Tuncel U. Reverse superior labial artery flap in reconstruction of nose and medial cheek defects. Ann Plast Surg. [Epub ahead-of-print September 13, 2013.] 19. Nakajima H, Imanishi N, Aiso S. Facial artery in the upper lip and nose: Anatomy and a clinical application. Plast Reconstr Surg. 2002;109:855–861; discussion 862. 20. Park C, Lineaweaver WC, Buncke HJ. New perioral arterial flaps: Anatomic study and clinical application. Plast Reconstr Surg. 1994;94:268–276. 21. Lazzeri D, Agostini T, Figus M, Nardi M, Pantaloni M, Lazzeri S. Blindness following cosmetic injections of the face. Plast Reconstr Surg. 2012;129:995–1012. 22. Feinendegen DL, Baumgartner RW, Vuadens P, et al. Autologous fat injection for soft tissue augmentation in the face: A safe procedure? Aesthetic Plast Surg. 1998;22:163–167.
Background: Previous studies have revealed a variation in the origin and distribution patterns of the facial artery. However, the relationship between the facial artery and the facial muscles has not been well described. The purpose of this study was to determine the facial artery depth and relationship with the facial musculature layer, which represents critical information for dermal filler injection and oral and maxillofacial surgery. Methods: Fifty-four embalmed adult faces from Korean cadavers (36 male and 18 female cadavers; mean age, 73.3 years) were used in this study. A detailed dissection was performed, with great care being taken to avoid damaging the facial artery underlying the facial skin and muscle. Results: The facial artery was first categorized according to the patterns of its final arterial branches. The branching pattern was classified simply into three types: type I, nasolabial pattern (51.8 percent); type II, nasolabial pattern with an infraorbital trunk (29.6 percent); and type III, forehead pattern (18.6 percent). Each type was further subdivided according to the facial artery depth and relationship with the facial musculature layer as types Ia (37.0 percent), Ib (14.8 percent), IIa (16.7 percent), IIb (12.9 percent), IIIa (16.7 percent), and IIIb (1.9 percent). Conclusion: This study provides new anatomical insight into the relationships between the facial artery branches and the facial muscles, including providing useful information for clinical applications in the fields of oral and maxillofacial surgery. (Plast. Reconstr. Surg. 135: 437, 2015.)
I
njectable filler treatments such as dermal filler injection have the advantages of being relatively noninvasive and simple; however, their use has been challenged by the menace of vascular complications.1–5 In particular, the direct impingement of a needle may result in numerous vascular complications, ranging from slight bruising to blindness, which is the most feared complication. Consideration of the course of the facial artery and application of a cannula with a blunt tip might almost guarantee a safe manipulation.6 From the Department of Dental Hygiene, School of Health and Medicine, Namseoul University; the Department of Anatomy, College of Medicine, Dankook University; the Division of Anatomy and Developmental Biology, Department of Oral Biology, Human Identification Research Center, BK21 PLUS Project, Yonsei University College of Dentistry; the Section of Dentistry and Maxillofacial Surgery, Department of Surgery, University of Verona; and the Department of Anatomy, Ewha Womans University School of Medicine. Received for publication February 8, 2014; accepted August 1, 2014. The first two authors contributed equally to this work. Copyright © 2015 by the American Society of Plastic Surgeons DOI: 10.1097/PRS.0000000000000991
However, given that use of a blunt tip and aspiration after placement of the needle or cannula cannot prevent vessel compression, this longestablished recommendation for avoiding direct injury appears to be insufficient to prevent vascular accidents by extravascular compression.7,8 The filler materials could be placed within the subcutaneous tissue or between the muscle fibers, or even injected into the space between the periosteum and the muscles. Clinically, the physician can manipulate the subcutaneous layer into which the instrument is placed by pinching the skin to allow targeting of subcutaneous injections, or by recognizing when bone contact has occurred for deep filler injections. With dermal filler injection in particular, selection of the proper injection layer is imperative for aesthetic considerations, to ensure provision of the proper volume, and to prevent numbness and the diffusion of fillers from the injection space. Therefore, knowledge of the relationship between the facial artery and Disclosure: The authors have no financial interest to declare in relation to the content of this article.
www.PRSJournal.com
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Plastic and Reconstructive Surgery • February 2015 its neighboring structures in the various subcutaneous layers is necessary to enable selection of the most appropriate space and passage of the filler materials to prevent iatrogenic injury by intravascular or extravascular accident. Unfortunately, the descriptions of facial artery anatomy published to date lack the details of not only its course and ramifying patterns (and possible variations thereof) but also its relationships in the various subcutaneous layers. More definitive data are required than the currently available ambiguous description of the facial artery presenting a tortuous course from the premasseteric area to the angular area for safe manipulation during injectable treatments. The aim of the present study was to elucidate the details of the course of the facial artery in the various subcutaneous layers, and to shed light on how the facial artery proceeds within the neighboring tissues by means of detailed and careful dissection.
MATERIALS AND METHODS Dissection of the Facial Artery and the Facial Muscles Fifty-four embalmed adult faces from Korean cadavers (36 male and 18 female cadavers; mean age, 73.3 years) were used in this study. All cadaveric objects in this study were legally donated to Yonsei Medical Center. The skin and subcutaneous tissue were carefully removed by detailed dissection, preserving the facial artery branches and their courses on the surface of the facial muscles, with great care being taken to avoid causing any damage. The course of the facial artery branches on the surface of each facial muscle was then recorded, sketched, and photographed. The facial artery was sketched by tracking it from the inferior border of the mandible to its terminal branches, and by cutting and retracting the facial muscles without damaging the facial artery branches to reveal its course. Classification of the Facial Artery According to the Terminal Branch and in Relation to the Facial Muscle The major facial artery branches were divided into the inferior labial artery, superior labial artery, inferior alar artery, angular artery, and lateral nasal artery according to their course, location, and distribution areas. In this study, the facial artery was classified into three types on the basis of the general artery classification according to the anatomical pattern of each facial artery terminal branch. Facial arteries running toward the nasion
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without forming angular artery and with branches around the lips and nose were classified as type I (nasolabial pattern). In type I, the facial artery ended as the lateral nasal artery (Fig. 1, above). Those running in the same direction as type I but forming nasolabial and infraorbital trunks were classified as type II (nasolabial pattern with an infraorbital trunk). The nasolabial trunk originated from the facial artery near the cheilion after branching off from the inferior labial artery, and then proceeded toward the upper lip, the nasal septum, and the lateral side of the nose next to the nasal ala. The infraorbital trunk was defined as the vertically independent and separate arterial branch from the facial artery that ran a deviated course toward the infraorbital and nasojugal area (Fig. 1, center). The nasolabial trunk bifurcates into the superior labial artery, inferior alar artery, and lateral nasal artery, whereas the infraorbital trunk runs inferiorly toward the orbital region and forms the angular artery. In type III (forehead pattern), the terminal branch of the facial artery ended as an angular artery, an anastomotic branch with the dorsal nasal artery (Fig. 1, below). In addition, the facial artery branches of all specimens passed either over or beneath the facial muscles in the perioral and infraorbital regions. Therefore, each facial artery type (i.e., type I to III) was further subdivided according to its depth and its relationship to the facial musculature layer (a and b) (Fig. 1).
RESULTS Location of the Facial Artery Branches Relative to the Facial Muscles Type I (a and b; nasolabial pattern) was observed in 51.8 percent (28 of 54) of cases (Fig. 1, above), with type Ia being the most frequent [20 of 54 (37.0 percent)]. In the lower lip, the facial artery was covered by the platysma and the depressor anguli oris, and gave off a branch of the inferior labial artery deep to the depressor labii inferioris. At the lateral modiolar region, the facial artery was located anterior to the buccal fat pad between the risorius and the zygomaticus major. Superior to the mouth corner, the inferior labial artery and superior labial artery divided from the facial artery, superficial to the orbicularis oris, before reaching the vermilion border of the upper and lower lips. The facial artery then ascended deep to the levator labii superioris and levator labii superioris alaeque nasi. At the nasal alar region, the inferior alar artery and lateral nasal artery supplying the
Volume 135, Number 2 • Facial Artery and Facial Muscle columella and the nose tip ramified from the facial artery deep to the levator labii superioris and the zygomaticus minor (Fig. 2). In type Ib [eight of 54 (14.8 percent)], all facial artery branches were located deep to facial muscles. Type II (a and b; nasolabial pattern with an infraorbital trunk) was observed in 16 of 54 cases (29.6 percent) (Fig. 1, center). In type IIa [nine of 54 (16.7 percent)], the nasolabial trunk ran similarly to type Ib, covered by the facial muscles. However, the infraorbital trunk ran toward the infraorbital area, superficial to the zygomaticus major and deep to the zygomaticus minor. It then turned medially toward the nasojugal area along the lower border of the orbicularis oculi and superficial to the levator labii superioris and levator labii superioris alaeque nasi, and ended as the angular artery. In type IIb [seven of 54 (12.9 percent)], the nasolabial trunk ran similarly to type Ia, and the infraorbital trunk was superficial to the zygomaticus major, zygomaticus minor, and levator labii superioris in the infraorbital and nasojugal areas (Fig. 3). Type III (forehead pattern) was identified in 10 of 54 cases (18.6 percent), and ended as the angular artery (Fig. 1, below). During its course, the type IIIa facial artery [nine of 54 (16.7 percent)] was not covered by the facial muscles at the upper lip, lateral to the margin of the orbicularis oris (nasolabial fold), and at the lateral area of the dorsum of nose (angular region) (Fig. 4). Type IIIb was found in one case (1.9 percent), in which the deep facial artery trunk ran through the infraorbital area located beside the main trunk of facial artery branches shown for type IIIa. This additional arterial trunk, which coursed deep to the facial muscles, joined with the branches of the infraorbital artery and ran toward the lateral side of the nose.
DISCUSSION Clinical knowledge of facial artery anatomy, including its depth, is required when performing facial dermal filler injection, rather than simply its location or the distribution of its branches. Although there are many reports on the classification of the facial artery branches and their distribution in the facial region, very few studies have explored their depth.9–14 Ultrasonography provides accurate information regarding the location of the facial arteries in individual patients, but one disadvantage of this tool is that it is difficult to detect small dermal vessels or to confirm their relationships with the facial muscles. The prevalence of complications caused
by serious skin necrosis has recently been reduced as a result of the use of a blunt cannula instead of a sharp needle. However, the side effects of injecting filler materials into subcutaneous tissues remain an issue because of the lack of anatomical knowledge regarding the relationship between the depth of the facial artery and the facial musculature layer.4,6 General anatomy textbooks report that the facial artery proceeds toward the oral commissure and ascends along the lateral side of the nose15; this description reflects the type I (51.8 percent, nasolabial pattern) or the type III (18.6 percent, forehead pattern) patterns described in the present study. Because types I and III (71.4 percent) were observed more frequently than type II (29.6 percent) in this study, besides the general description of the courses of facial artery, patterns identical to a type II facial artery were also observed (Fig. 1). In particular, the type II pattern (29.6 percent, nasolabial pattern with an infraorbital trunk) should be considered, where the infraorbital trunk is located superficial to the zygomaticus major and levator labii superioris. There are also rare reports of a type II pattern, with the additional facial artery trunk running in the infraorbital and nasojugal areas.10,12,16 Physicians should take care to consider the facial muscle and the facial artery when they inject soft-tissue fillers into this region because bruising or vascular accidents resulting from extravascular compression occasionally occur in the skin during dermal filler injection (Figs. 1, center, and 3). Future studies should investigate more specimens and consider the possibility of racial differences in the course of the facial artery. However, it can already be speculated from the present findings that knowledge of the coursing pattern of the infraorbital trunk in the type II facial artery is important for a complete understanding of the distribution of the facial artery in the face. The facial artery branches were located in the subcutaneous layer in the superomedial region of the mouth corner (between the cheilion and the nasal ala) and on the surface of the facial muscle in 85.2 percent of cases (46 of 54). In particular, erythema, bruising, and superficial skin necrosis are quite likely to occur during filler injection into this region because the facial artery branches are located immediately below the facial skin. Therefore, special attention should be paid when injecting fillers into this region. Koh et al. reported that the facial artery proceeded upward in the vicinity of the nasolabial fold in 88 percent.10 Yang et al. reported that the facial artery proceeded along the nasolabial fold in 93.3
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Fig. 1. The three patterns of the facial artery (FA) encountered in this study, with illustrations of the course of the facial artery relative to the facial muscles. Each type was subdivided according to the location of the
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Fig. 2. Photographs and illustration showing type Ia (nasolabial pattern) based on the courses of facial arterial branches and facial muscles. Facial skin and subcutaneous tissue were eliminated without damaging the facial arterial branches. (Left) Arrowheads indicate the facial arterial branches superficial to the facial muscle. (Center) The facial muscles were cut and retracted to allow observation of the facial artery branches traveling deep into them. Facial artery branches: IA, inferior alar artery; IL, inferior labial artery; LN, lateral nasal artery; and SL, superior labial artery. Facial muscles: DAO, depressor anguli oris; DLI, depressor labii inferioris; LAO, levator anguli oris; LLS, levator labii superioris; LLSAN, levator labii superioris alaeque nasi; OOc, orbicularis oculi; OOr, orbicularis oris; Pl, platysma; Ri, risorius; Zmi, zygomaticus minor; and ZMj, zygomaticus major.
percent and the artery was located within 5 mm of the fold in 42.9 percent.17 They mentioned also that the facial artery crossed the nasolabial fold in 33.9 percent, and reported a case where the facial artery was located within the muscle fibers
Fig. 1. (Continued) facial artery relative to the facial musculature layer. To help distinguish between the superficial and deep courses of the facial artery, the color of the facial artery coursing beneath the facial muscles is lighter than its superficial course, which runs on top of the facial muscles. (Above) Type I, nasolabial pattern. (Center) Type II, nasolabial pattern with an infraorbital trunk; purple and pink colors of the facial artery branches (FAb) indicate the nasal and infraorbital trunks, respectively. (Below) Type III, forehead pattern. Facial artery branches: Ag, angular artery; DFAt, deep FA trunk; IA, inferior alar artery; IL, inferior labial artery; IO, infraorbital artery; LN, lateral nasal artery; and SL, superior labial artery. Facial muscles: DAO, depressor anguli oris; DLI, depressor labii inferioris; LAO, levator anguli oris; LLS, levator labii superioris; LLSAN, levator labii superioris alaeque nasi; OOc, orbicularis oculi; OOr, orbicularis oris; Pl, platysma; Ri, risorius; Zmi, zygomaticus minor; and Zmj, zygomaticus major.
reaching the skin of the fold. Thus, the area near the nasolabial fold would be susceptible to vascular injury during injectable treatment. Considering the diversity and unpredictability of depth of the arterial location in the present study, it can be speculated that aspiration before injection into the nasolabial fold should be performed regardless of the depth of injection. The nasolabial region is a donor area for local skin flaps (skin, mucosal, and musculomucosal flaps). This region has a rich supply of blood through the facial artery branches.14,18 Based on the present findings, the inferior labial artery, which is distributed close to the lower lip, is located deeper than the depressor anguli oris and the depressor labii inferioris in most cases; however, the location of the superior labial artery varies widely, and includes cases where the superior labial artery penetrates through the orbicularis oris to run along the surface and then into the deep region. In other cases, it runs in the deep region of the orbicularis oris and then penetrates through it to emerge at the site of the nasal tip to
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Fig. 3. Photograph and illustration showing type IIb (nasolabial pattern with an infraorbital trunk). A deeper dissection was performed in which the facial muscles were cut and retracted while preserving the facial artery (FA). The yellow arrowheads indicate the facial artery branches of the subcutaneous layer between the facial skin and the facial muscles. The illustration shows the facial artery depth relative to the facial muscles. Facial artery branches: Ag, angular artery; IA, inferior alar artery; IL, inferior labial artery; LN, lateral nasal artery; and SL, superior labial artery. Facial muscles: DAO, depressor anguli oris; DLI, depressor labii inferioris; LAO, levator anguli oris; LLS, levator labii superioris; LLSAN, levator labii superioris alaeque nasi; OOc, orbicularis oculi; OOr, orbicularis oris; Pl, platysma; Ri, risorius; Zmi, zygomaticus minor; and ZMj, zygomaticus major.
form septal branches. Therefore, the information on the course and location of the facial artery presented in this study would be helpful to physicians during flap surgery. The angular artery is known to be vulnerable to iatrogenic injury during dermal filler injection in the sellion area and the dorsum of the nose. The frequency of angular artery ramification from the facial artery has been variously reported as 72 percent, 68 percent, 40.7 percent, 22 percent, and 4 percent, by Nakajima et al., Niranjan, Koh et al., Pinar et al., and Mitz et al., respectively.10,12–14,19 An angular artery was observed in 48.2 percent of the present cases (types II and III) (Figs. 3 and 4). Areas with an insufficient blood supply from the facial artery are supplied by the branches of the maxillary or internal carotid artery.13,20 A supplementary artery derived from the ophthalmic artery was shown to supply the angular area in the case
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where the facial artery lacked an angular artery.20 Because the ophthalmic artery was also distributed superficial to the facial expression muscles in some parts of the forehead, superficial injection of dermal filler to the angular area should be performed meticulously and with great caution, regardless of the origin of the angular artery. Lazzeri et al. reported cases of blindness following arterial impingement during dermal filler injection, and recommended various technical tips to reduce the risk of vascular accidents. In their report, small-tipped needles and cannulae were recommended because of their slow injection speed and thus reduced possibility of causing vascular occlusion.21 However, the physician needs to know the precise anatomy of arterial distribution in the treated area before performing surgical protocols. Knowledge of the possible courses of the facial artery without consideration of the
Volume 135, Number 2 • Facial Artery and Facial Muscle
Fig. 4. Photograph and illustration showing type IIIa (forehead pattern). Yellow arrowheads indicate the facial arterial branches in the subcutaneous tissue. The illustration shows the facial artery (FA) depth relative to the facial muscles. Facial artery branches: Ag, angular artery; IA, inferior alar artery; IL, inferior labial artery; LN, lateral nasal artery; SL, superior labial artery. Facial muscles: DAO, depressor anguli oris; DLI, depressor labii inferioris; LAO, levator anguli oris; LLS, levator labii superioris; LLSAN, levator labii superioris alaeque nasi; OOc, orbicularis oculi; OOr, orbicularis oris; Pl, platysma; Ri, risorius; Zmi, zygomaticus minor; and ZMj, zygomaticus major.
muscle layer is not adequate for injectable treatment to the face. Feinendegen et al. reported that dermal filler injection to the nasolabial fold using a 2-mm-diameter cannula resulted in global aphasia and mild sensorimotor hemiparesis on the right side; a radiologic examination revealed that the temporoparietal area of the left middle cerebral artery was infarcted.22 Based on that case, the use of a blunt injector tip does not seem to be able to completely prevent placement of the injectable in cases of limited knowledge of the ambiguous description of the facial artery running from the premasseteric notch to the nasion through the nasolabial fold. Despite the variations in the facial artery course described in this article, it has been demonstrated that facial artery branches on the nasolabial fold, inferolateral area to the mouth corner, and area lateral to the ala are frequently positioned subcutaneously. These areas are often manipulated during dermal filler injection for esthetic purposes. Therefore, the subcutaneous injection of dermal
filler materials—including hyaluronic acid and autogenous adipose tissues—to the nasolabial fold would carry with it a high risk of vascular damage.
CONCLUSIONS In this study, the course of the facial artery is classified into three types, the details of which are observed separately, according to the locations of the facial artery branches as they coursed either along the surface or in the deep regions of the facial muscles. The results of this study suggest that constant movement of the needle tip helps to avoid intravascular injection into arteries located in the subcutaneous tissues and reduces the likelihood of the side effect of arterial compression, particularly during facial dermal filler injection. Hee-Jin Kim, D.D.S., Ph.D. Department of Oral Biology, Room 601 Yonsei University College of Dentistry 50 Yonsei-Ro Seodaemun-Gu, Seoul 120-752, Republic of Korea [email protected]
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Plastic and Reconstructive Surgery • February 2015 acknowledgments
This work was supported by the National Research Foundation of Korea grant funded by the Korea government (Ministry of Education, Science & Technology) (no. 2011-0007612). We thank Sang-Hoon Kwon at New York University College of Arts and Science and SoYeon Kim at Georgetown University, College of Arts and Science, for assistance in revising the article and anatomical procedure. All authors were well-informed of the World Medical Association Declaration of Helsinki, Ethical Principles for Medical Research involving Human Subjects, and confirmed that the present study firmly fulfilled the declaration. None of the authors has financial or private relationships with commercial, academic, or political organizations or people that could have improperly influenced this research. All cadaveric objects in this study were legally donated Yonsei Medical Center. REFERENCES 1. Newman J. Review of soft tissue augmentation in the face. Clin Cosmet Investig Dermatol. 2009;2:141–150. 2. Ozturk CN, Li Y, Tung R, Parker L, Piliang MP, Zins JE. Complications following injection of soft-tissue fillers. Aesthet Surg J. 2013;33:862–877. 3. Daines SM, Williams EF. Complications associated with injectable soft-tissue fillers: A 5-year retrospective review. JAMA Facial Plast Surg. 2013;15:226–231. 4. Cohen JL. Understanding, avoiding, and managing dermal filler complications. Dermatol Surg. 2008;34(Suppl 1):S92–S99. 5. Grunebaum LD, Bogdan Allemann I, Dayan S, Mandy S, Baumann L. The risk of alar necrosis associated with dermal filler injection. Dermatol Surg. 2009;35(Suppl 2):1635–1640. 6. Fulton J, Caperton C, Weinkle S, Dewandre L. Filler injections with the blunt-tip microcannula. J Drugs Dermatol. 2012;11:1098–1103. 7. Park TH, Seo SW, Kim JK, Chang CH. Clinical experience with hyaluronic acid-filler complications. J Plast Reconstr Aesthet Surg. 2011;64:892–896. 8. Shumaker PR, Sakas EL, Swann MH, Greenway HT Jr. Calcium hydroxylapatite tissue filler discovered 6 years
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after implantation into the nasolabial fold: Case report and review. Dermatol Surg. 2009;35(Suppl 1):375–379. 9. Aratani R. Anatomical Study of the External Carotid Artery of Japanese: Facial Artery (dissertation). Tokyo: Tokyo Dental College; 1960. 10. Koh KS, Kim HJ, Oh CS, Chung IH. Branching patterns and symmetry of the course of the facial artery in Koreans. Int J Oral Maxillofac Surg. 2003;32:414–418. 11. Lohn JW, Penn JW, Norton J, Butler PE. The course and variation of the facial artery and vein: Implications for facial transplantation and facial surgery. Ann Plast Surg. 2011;67:184–188. 12. Pinar YA, Bilge O, Govsa F. Anatomic study of the blood supply of perioral region. Clin Anat. 2005;18:330–339. 13. Mitz V, Ricbourg B, Lassau JP. Facial branches of the facial artery in adults: Typology, variations and respective cutaneous areas (in French). Ann Chir Plast. 1973;18:339–350. 14. Niranjan NS. An anatomical study of the facial artery. Ann Plast Surg. 1988;21:14–22. 15. Standring S. Gray’s Anatomy: The Anatomical Basis of Clinical Practice. Edinburgh: Elsevier/Churchill Livingstone; 2008. 16. Furukawa M, Mathes DW, Anzai Y. Evaluation of the facial artery on computed tomographic angiography using 64-slice multidetector computed tomography: Implications for facial reconstruction in plastic surgery. Plast Reconstr Surg. 2013;131:526–535. 17. Yang HM, Lee JG, Hu KS, et al. New anatomical insights on the course and branching patterns of the facial artery: Clinical implications of injectable treatments to the nasolabial fold and nasojugal groove. Plast Reconstr Surg. 2014;133:1077–1082. 18. Turan A, Kostakoglu N, Tuncel U. Reverse superior labial artery flap in reconstruction of nose and medial cheek defects. Ann Plast Surg. [Epub ahead-of-print September 13, 2013.] 19. Nakajima H, Imanishi N, Aiso S. Facial artery in the upper lip and nose: Anatomy and a clinical application. Plast Reconstr Surg. 2002;109:855–861; discussion 862. 20. Park C, Lineaweaver WC, Buncke HJ. New perioral arterial flaps: Anatomic study and clinical application. Plast Reconstr Surg. 1994;94:268–276. 21. Lazzeri D, Agostini T, Figus M, Nardi M, Pantaloni M, Lazzeri S. Blindness following cosmetic injections of the face. Plast Reconstr Surg. 2012;129:995–1012. 22. Feinendegen DL, Baumgartner RW, Vuadens P, et al. Autologous fat injection for soft tissue augmentation in the face: A safe procedure? Aesthetic Plast Surg. 1998;22:163–167.
