Download Variability of the Postauricular Muscle Complex

ORIGINAL ARTICLE
Variability of the Postauricular Muscle Complex
Analysis of 40 Hemicadaver Dissections
Aldo Benjamin Guerra, MD; Stephen Eric Metzinger, MD; Rebecca Crawford Metzinger, MD;
Chen Xie, MD; Yue Xie, MHA; Peter Lister Rigby, MD; Thomas Naugle, Jr, MD
Background: The postauricular area is often explored
by reconstructive and otologic surgeons. We previously
reported on the use of postauricular tissues as a graft for
wrapping hydroxyapatite implants in orbital reconstruction. This procedure reduced the incidence of implant
exposure, while achieving acceptable cosmetic results.
Although much is known about the postauricular area,
muscle and fascial relationships and potential variations in anatomy remain ill defined.
Objectives: To identify and analyze variations in the
patterns of the postauricular muscle complex (PMC) and
to study the relationships of the fascial contributions from
the components that make up the PMC.
Methods: Dissections were performed using 40 fresh
specimens. Muscular and fascial components of the PMC
were dissected, analyzed, and photographed.
Results: The PMC receives contributions from the
occipitalis and trapezius muscles, the deep temporal
T
From the Aesthetic Surgical
Associates, Metairie, La
(Drs Guerra and S. E.
Metzinger), the Department
of Ophthalmology, Tulane
University Medical Center,
New Orleans, La (Drs R. C.
Metzinger and Naugle), and the
Department of Otolaryngology
(Dr Xie and Mr Xie) and the
Department of Surgery, Section
of Plastic and Reconstructive
Surgery (Dr Rigby), Louisiana
State University Health
Sciences Center, New Orleans.
and sternocleidomastoid fasciae, and the superior and
posterior auricular and platysma muscles. Major contributors to the PMC were present in every specimen.
Minor contributors were more variable in their presence and contributions. The posterior auricular
muscle was identified as having several muscle
bundles in 1 specimen and absent in 2 specimens
(5%). The occipitalis fascia was seen to insert superior
to the auricle and to blend with the deep temporal fascia in 3 cases (7%). The platysma muscle contributed
to the PMC in 8 cases (20%).
Conclusions: This study demonstrated important variations in the presence and contributions of 7 previously
known muscular structures and their role in forming the
PMC. Seven distinct patterns are identified, and the potential clinical implications of these anatomical variations are illustrated.
Arch Facial Plast Surg. 2004;6:342-347
HE POSTAURICULAR AREA IS
frequented in clinical practice for otologic, reconstructive, and aesthetic purposes. Important structures
in this area include the trapezius, occipitalis, and extrinsic auricular muscles and the
temporalis and sternocleidomastoid fasciae.1-5 Investigators in previous studies have
found these structures to be reliable.2 However, descriptions of potential anatomical
variations and the relationships that these
musculofascial structures share with each
other have not been fully elucidated. Anatomical variations in the postauricular area
may alter the results and design of vascularized flaps and musculofascial grafts harvested from this area. Also, these variations could have clinical implications in
otologic and otoplastic surgery.
Vascularized tissue transfers from the
postauricular area have various applications in reconstructive surgery.6-9 As with
any other part of the body, a sound understanding of the anatomy of the postauricular area is necessary to ensure that such
(REPRINTED) ARCH FACIAL PLAST SURG/ VOL 6, SEP/OCT 2004
342
transfers are safely carried out. Retroauricular grafts, on the other hand, can be used
as alternatives to vascularized tissue, depending on recipient site requirements. For
instance, small retroauricular grafts have
been used successfully in lip augmentation.10 Also, agenesis, hypoplasia, neuromuscular dysfunction, and proximal insertion of the posterior auricular muscle have
been implicated in the etiology of protruding ears.11-13 Similarly, it has been suggested that absence of the superior auricular muscle plays a role in the pathogenesis
of lop ear.11-14 Potential therapeutic maneuvers in the treatment of the protruding ear
are likely to be influenced by the underlying surgical anatomy.
METHODS
Forty fresh hemicadaver heads were used in this
anatomical study. To standardize the experiment, 1 surgeon (C.X.) performed all the dissections. Photographs were obtained using a
35-mm camera with a 105-macro lens for all
specimens. Distance and lighting were standardized in all cases. The ethnicity and sex of
WWW.ARCHFACIAL.COM
©2004 American Medical Association. All rights reserved.
Downloaded From: http://archfaci.jamanetwork.com/pdfaccess.ashx?url=/data/journals/faci/11759/ on 06/19/2017
Figure 1. Photograph of cadaver specimen demonstrating the type 1 pattern, which was seen 68% of the time and was the most common pattern noted. The
illustration demonstrates the presence of the major and minor contributors to the postauricular muscle complex. In this pattern, the platysma muscle is not part of
the complex. White indicates fascial confluence; green, occipitalis; pink, temporalis; blue, trapezius; striped, sternocleidomastoid; dark red, posterior auricular;
dark blue, superior auricular; and sky blue, platysma.
the specimens were recorded. Incisions were made along the
postauricular crease starting 3 mm above the auricle. Two horizontal incisions were extended from the superior and inferior
aspect of the auricle to facilitate elevation of the skin–soft tissue envelope. The skin and subcutaneous tissues were dissected from the underlying muscular and fascial structures and
the cranium. Each hemicadaver dissection was plotted to document the different patterns of muscle and fascia contributing
to the postauricular muscle complex (PMC).
RESULTS
Twenty male and 20 female hemicadaver heads were
dissected. One female specimen was Hispanic, and 1
male specimen was African American. The rest of the
specimens were white. In all specimens, the PMC was
found to have contributions from the occipitalis
muscle, trapezius muscle, temporalis fascia, and sternocleidomastoid muscular fascia. These 4 musculofascial components were considered to be the major contributors to the area. Minor contributors to the PMC
were the posterior auricular, superior auricular, and
platysma muscles. The minor contributors were muscular and did not contribute significant fascial components to the PMC. The greatest variability occurred
as a result of the presence or absence of minor contributors and occipitalis muscle-fascial components.
Interestingly, all these muscle groups are located
more superficially in the retroauricular area and in
the same plane as the superficial musculoaponeurotic system and platysma of the face. The platysma
muscle contributed to the PMC only 20% of the time.
The superior auricular muscle was present in 35 specimens (88%), and the posterior auricular muscle was
present in 38 specimens (95%). Also, 4 separate mus-
cular bundles were seen in 1 posterior auricular
muscle specimen. The occipitalis muscular fascia
extended anteriorly to cover the temporalis fascia in 3
cases (7%).
We classified the patterns into 7 distinct types as
follows:
Type
No. (%)*
1
27 (68)
2
7 (18)
3
1 (2)
4
1 (2)
5
1 (2)
6
2 (5)
7
1 (2)
*Percentages do not total 100 because of rounding.
In type 1, which was the most common pattern seen
(68%), the specimens contained the 4 major contributors: the occipitalis and trapezius muscles, the temporalis and sternocleidomastoid fasciae, and the extrinsic
auricular muscles without platysma (Figure 1). In
type 2, which was the second most common pattern
seen (18%), the specimens contained all the major and
minor contributors (Figure 2). In type 3, the specimen contained all the major and minor components
except for the superior auricular muscle (Figure 3).
The type 4 specimen contained all the major contributors, with the posterior auricular muscle being the only
minor contributor (Figure 4). The type 5 specimen
lacked all 3 of the minor contributors, with the occipitalis muscular fascia extending forward to the superior
point of the auricle and blending with the temporalis
muscle fascia (Figure 5). In type 6 specimens, the
posterior auricular muscle was found along with the
anterior occipitalis muscular fascial extension that
(REPRINTED) ARCH FACIAL PLAST SURG/ VOL 6, SEP/OCT 2004
343
WWW.ARCHFACIAL.COM
©2004 American Medical Association. All rights reserved.
Downloaded From: http://archfaci.jamanetwork.com/pdfaccess.ashx?url=/data/journals/faci/11759/ on 06/19/2017
Figure 2. The second most common pattern noted was type 2 (18%). In this case, the major and minor contributors to the postauricular muscle complex are
present. The platysma muscle contributes to the inferior portion of the complex. In this particular specimen, the posterior auricular muscle was noted to be broad,
and final dissection revealed 4 separate muscle bundles, with an intervening ligament between the 2 inferiorly located bundles.
Figure 3. In 1 case, the postauricular muscle complex was made up of all the minor and major contributors, except for the superior auricular muscle. No obvious
external ear deformity was noted in this specimen.
blends with the temporalis fascia (Figure 6). The
type 7 specimen contained all the major contributors,
with the superior auricular muscle being the only
minor contributor (Figure 7).
COMMENT
The occipitalis, trapezius, sternocleidomastoid, and auricular muscles have previously been described as being
significant components of the PMC. Our study demonstrated that 7 structures can contribute to the PMC. In our
study, the major contributors to the PMC, which were present in every specimen, were the occipitalis and trapezius
muscles and the temporalis and sternocleidomastoid fasciae. Partial absence of the trapezius muscle has been reported but is thought to be extremely rare.15 The trapezius and sternocleidomastoid muscles arise from a common
premuscle mass during gestation, and there have been re-
(REPRINTED) ARCH FACIAL PLAST SURG/ VOL 6, SEP/OCT 2004
344
WWW.ARCHFACIAL.COM
©2004 American Medical Association. All rights reserved.
Downloaded From: http://archfaci.jamanetwork.com/pdfaccess.ashx?url=/data/journals/faci/11759/ on 06/19/2017
Figure 4. The type 4 pattern is very similar to the type 3 pattern, except that the platysma contribution was absent from the postauricular muscle complex in this case.
Figure 5. In this pattern, all 3 of the minor contributors to the postauricular muscle complex were absent. Notably, the occipitalis muscle fascia extended forward
and fused with both the temporalis muscle fascia superiorly and the sternocleidomastoid muscle fascia inferiorly.
ports of anomalies within these muscles.15-17 The fascial
provisions of the major contributors to the PMC were noted
to be strong, reliable, and capable of holding sutures. The
presence and components of the minor contributors to the
PMC were more variable than those of the major contributors. In the group of minor contributors, the muscle
found most consistently was the posterior auricular muscle,
which was present in 38 (95%) of the 40 cases. The extrinsic auricular muscles have been well documented.3-5
The posterior auricular muscle has been described as a
double-bellied flat muscle with an intervening ligament.2 In 1 specimen, this muscle was identified as having 4 separate bundles. Similar variations have been observed by others.7 Also, the minor contributors to the PMC
were found to be completely absent in 1 case (type 5).
The anterior fascial extension of the occipitalis muscle
to the temporalis fascia served to replace these components. In 1 case, extension of the occipitalis muscle fascia occurred concurrently with a posterior auricular
muscle (type 7).
(REPRINTED) ARCH FACIAL PLAST SURG/ VOL 6, SEP/OCT 2004
345
WWW.ARCHFACIAL.COM
©2004 American Medical Association. All rights reserved.
Downloaded From: http://archfaci.jamanetwork.com/pdfaccess.ashx?url=/data/journals/faci/11759/ on 06/19/2017
Figure 6. In the type 6 pattern, the occipitalis fascia extended forward and fused with the fascia of the temporalis muscle. A posterior auricular muscle is present
in this pattern and is enveloped by fascial extensions from the occipitalis and sternocleidomastoid muscle fasciae, forming the postauricular muscle complex.
Figure 7. In this case, the occipitalis fascial extensions appeared normal, but no posterior auricular muscle was noted on dissection. A dense fascial band replaced
the muscle. This structure developed as a thickening of the postauricular fascia that extended from above and below.
Absence or dysfunction of auricular muscles has been
implicated in the pathogenesis of certain ear deformities.11-14 Of note, none of our cadavers was found to have
abnormalities of the external ear, implying that despite
variations, patients may not manifest obvious deformities of the auricle. Based on our dissections, it appears
that other structures involved in the PMC can compensate for the deficient extrinsic muscles (types 5 and 7).
The etiology of protruding and lop ears is multifacto-
rial, although intrinsic and extrinsic auricular muscles
play major roles in the ultimate shape and position of the
auricle. Functionally, in vertebrates, postauricular muscles
are used to identify potential mates and predators, as well
as in fight-or-flight reflexes. In humans, extrinsic muscles
respond to sound stimuli when studied with electromyographic techniques and maintain involuntary function.14 There is a linear relationship between ear projection and insertion site of the posterior auricular muscle
(REPRINTED) ARCH FACIAL PLAST SURG/ VOL 6, SEP/OCT 2004
346
WWW.ARCHFACIAL.COM
©2004 American Medical Association. All rights reserved.
Downloaded From: http://archfaci.jamanetwork.com/pdfaccess.ashx?url=/data/journals/faci/11759/ on 06/19/2017
in patients with and without protruding ears.18 However, Furnas19 and Mustarde20 recommend resection of
the posterior auricular muscle in correction of the prominent ear. An alternative reconstruction for protruding ears
involves transposing the insertion of the posterior auricular muscle onto the concha.21 In principle, this technique corrects valgus of the concha and underfolding of
the antihelix. Azad et al22 have combined transposition
with anterior conchal scoring and concha-mastoid sutures. Anterior transposition of the posterior auricular
muscle has been found to be a useful adjunct in our hands.
Patients with patterns 5 and 6 are not candidates for transposition because they lack a posterior auricular muscle.
Use of the retroauricular fascial layer in transfer of vascularized tissues for various reconstructive procedures has
been reported.23-25 Clearly, a thorough knowledge of the
vasculature of these flaps is important for successful flap
transfer.5,7,26-29 However, based on our findings, we estimate that retroauricular fasciae and its variations play a significant role in providing an additional margin of safety in
flap transfer. This margin of safety is evident in clinical reports, which use fasciae to carry random-pattern or axial
circulation to skin components.26-29 To access the vessels
and to free the deeper (temporalis) fascia, which carries the
flap, the more superficial structures must be divided, as previously described.29 If the superficial anatomy of the retroauricular area is aberrant, the flap vasculature may be damaged during surgery, as the appropriate dissection plane
may be difficult to identify. Venous insufficiency is also related to the underlying muscle and fascial anatomy as well
as to greater anatomical variability of veins.27 Although we
did not specifically describe the relationships between the
PMC and the venous drainage, we believe that the fascial
structures and their variations play an important role in dissipating venous congestion. Several authors have already
recommended widening the amount of fascia harvested to
increase venous drainage.29,30
The retroauricular fascia can also be extremely useful as a graft. While variations do exist, the fascial layer is
consistently thick enough to provide for a durable graft.6,7
The PMC fascia grafts are important in challenging situations, such as the wrapping of hydroxyapatite spheres in
postenucleation socket reconstruction. Long-term follow-up has demonstrated the reliability of this technique.6 As substitutes for other tissues, postauricular fascia grafts are thought to be superior alternatives to dermal
fat grafts and superficial musculoaponeurotic system grafts
in cosmetic lip augmentation.10 Retroauricular fascia is
thicker and sturdier than both dermal fat grafts and superficial musculoaponeurotic system grafts and seems to resist the dynamic forces of the orbicularis oris muscle.10 Other
authors have used the strong fascial layer for placement of
sutures in otoplatsy, with great reliability.19
We used fresh human cadavers to study the variations and relationships of the muscular and fascial components of the PMC. Our findings were obtained from a
small sample size, primarily elderly whites. Different ethnic groups may display patterns that are different from
those observed in the present study. Knowledge of these
anatomical variations can help in the planning and safe
transfer of vascularized tissue, in maneuvers for aes-
thetic and reconstructive otologic surgery, and in providing strong and reliable grafts in restoration of the globe.
Further study is needed to fully understand the relationship of the variations described and their potential effects on flap complications.
Accepted for publication June 10, 2004.
Correspondence: Aldo Benjamin Guerra, MD, Aesthetic Surgical Associates, 3939 Houma Blvd, No. 216, Metairie, LA 70006.
REFERENCES
1. Clemente CD. The ear. In: Gray’s Anatomy of the Human Body. Media, Pa: Lea &
Febiger; 1985:1315-1318.
2. Davis J. Surgical anatomy and technique. In: Aesthetic and Reconstructive Otoplasty. New York, NY: Springer-Verlag NY Inc; 1986:80-90.
3. Hollinshead HD. The ear, orbit and nose. In: Textbook of Anatomy. Philadelphia,
Pa: Harper & Row Publishers Inc; 1985:943-946.
4. Netter FH. Atlas of Human Anatomy. Summit, NJ: CIBA-Geigy Co; 1985:21.
5. Allison GR. Anatomy of the external ear. Clin Plast Surg. 1978;5:419-422.
6. Naugle TC, Lee AM, Haik BG, Callahan MA. Wrapping hydroxyapatite orbital implants with posterior auricular muscle complex grafts. Am J Ophthalmol. 1999;
128:495-501.
7. Talmi YP, Horowitz Z, Bedrin L, Kronenberg J. Auricular reconstruction with a
postauricular myocutaneous island flap: flip-flop flap. Plast Reconstr Surg. 1996;
98:1191-1199.
8. Farrior JB. Postauricular myocutaneous flap in otologic surgery. Otolaryngol Head
Neck Surg. 1998;118:743-746.
9. Krespi YP, Ries WR, Shugar JMA, Sisson JA. Auricular reconstruction with
postauricular myocutaneous flap. Otolaryngol Head Neck Surg. 1983;91:193196.
10. McCollough EG. Facelifting: evolution of a personal technique. Paper presented
at: 11th Annual Minimally Invasive Facial Aesthetic Course; May 22, 2004; New
Orleans, La.
11. Smith DW, Takashima H. Ear muscles and ear form. Birth Defects Orig Artic Ser.
1980;16:299-302.
12. Smith DW, Takashima H. Protruding auricle: a neuromuscular sign. Lancet. 1978;
1:747-749.
13. Zerin M, Van Allen MI, Smith DW. Intrinsic auricular muscles and auricular form.
Pediatrics. 1982;69:91-93.
14. Seiler R. Muscles of the external ear and their function in man, chimpanzees and
macaca [in German]. Gegenbaurs Morphol Jahrb. 1974;120:78-122.
15. Emsley JG, Davis MD. Partial absence of the trapezius muscle in a human cadaver. Clin Anat. 2001;14:383-386.
16. Goss CM. Anatomy of the Human Body. Media, Pa: Lea & Febiger; 1973:372396.
17. Sarikcioglu L, Donmez BO, Ozkan O. Cleidooccipital muscle: an anomalous muscle
in the neck region. Folia Morphol (Warsz). 2001;60:347-349.
18. Guyuron B, Deluca L. Ear projection and the posterior auricular muscle insertion. Plast Reconst Surg. 1997;100:457-460.
19. Furnas DW. Otoplasty for orotruding ears, cryotopia, or Stahl’s ear. In: Evans
GRD, Gregory RD, eds. Operative Plastic Surgery. New York, NY: McGraw-Hill
Co Inc; 2000:417-448.
20. Mustarde JC. Correction of prominent ears using buried mattress sutures. Clin
Plast Surg. 1978;5:459-464.
21. Nicoletis C, Guerin-Surville H. Prominent ears: transposition of the postauricular
muscle on the scapha: a new technique. Aesthetic Plast Surg. 1978;2:295-299.
22. Azad S, Edwin A, Kumar PV. Posterior auricular muscle—a useful adjunct in otoplasty. Br J Plast Surg. 2003;56:722-723.
23. Yoshimura K, Ouchi K, Wakita S, Uda K, Harii K. Surgical correction of cryptopia
with superiorly based superficial mastoid fascia and skin paddle. Plast Reconstr
Surg. 2000;105:836-841.
24. Park C, Shin SK, Kang HS, Lee YH, Lew JD. A new arterial flap from the postauricular surface: its anatomic basis and clinical application. Plast Reconstr Surg.
1988;82:498-505.
25. Guyuron B. Retroauricular island flap for eye socket reconstruction. Plast Reconstr Surg. 1985;76:527-533.
26. Yang D, Morris SF. Vascular basis of the retroauricular flap. Ann Plast Surg. 1998;
40:28-33.
27. Kolhe PS, Leonard AG. The posterior auricular flap: anatomical studies. Br J Plast
Surg. 1987;40:562-569.
28. Yotsuyanagi T, Watanabe Y, Yamashita K, Urushidate S, Yokoi K, Sawada Y. Retroauricular flap: its clinical application and safety. Br J Plast Surg. 2001;54:12-19.
29. Song R, Song Y, Qi K, Jiang H, Pan F. The superior auricular artery and retroauricular arterial island flaps. Plast Reconstr Surg. 1996;98:657-669.
30. Marty F, Montandon D, Gumerer R, Zbrowski A. Subcutaneous tissue in the scalp:
anatomical, physiological and clinical study. Ann Plast Surg. 1986;16:368-376.
(REPRINTED) ARCH FACIAL PLAST SURG/ VOL 6, SEP/OCT 2004
347
WWW.ARCHFACIAL.COM
©2004 American Medical Association. All rights reserved.
Downloaded From: http://archfaci.jamanetwork.com/pdfaccess.ashx?url=/data/journals/faci/11759/ on 06/19/2017