CASE REPORT
Surface Anatomy of the Ear Dusan Sajic, Jason Archibald, and Christian Murray Expert diagnosis of cutaneous pathology requires precise anatomic description. This brief report will review the clinically relevant surface anatomy of the ear. Bien connaıˆtre l’anatomie de l’oreille a des incidences sur le plan clinique en ce qui concerne l’e´volution des cancers de la peau sie´geant en des points particuliers et la complexite´ de la reconstruction chirurgicale. Le cas pre´sente´ ici et l’examen de l’anatomie de la surface de l’oreille aideront les cliniciens a` repe´rer ces points particuliers.
ONMELANOMA SKIN CANCER (NMSC) is the most common type of human cancer.1,2 It accounts for over 1 million new cases in the United States every year3,4 and over 80,000 new cases in Canada, more than cancers of the lung, colorectum, and breast combined.2 Although NMSC generally carries an excellent prognosis, with a very low mortality rate,5 several factors have important prognostic implications. These include the tumor size and type, immune status of the patient, and anatomic location of the lesion. Each of these can increase the burden of disease and necessitate more complicated treatment modalities.6 The two most common tumor types include basal cell carcinoma (BCC) and squamous cell carcinoma (SCC), with the former being approximately four to five times more common.7 The anatomy of the ear, with its highly contoured and richly vascularized architecture, represents a significant challenge for both tumor excision and repair. Specific anatomic subunits carry a worse prognosis in terms of both tumor recurrence, growth, or metastasis and cosmetic outcomes. An accurate dermatologic diagnosis, with precise anatomic terminology, greatly assists in the communication between the referring doctor, the surgeon,
N
Figure 1. Patient referred with a lesion on the right ear.
From the Division of Dermatology, University of Toronto, Toronto, ON, and the Division of Otolaryngology, McMaster University, Hamilton, Ontario. Address reprint requests to: Christian Murray, Division of Dermatology, University of Toronto, Women’s College Hospital, 76 Grenville Street, Toronto, ON M5S 1B2.
DOI 10.2310/7750.2013.13057 # 2014 Canadian Dermatology Association
Figure 2. Defect post–Mohs surgery for sclerosing basal cell carcinoma.
Canadian Dermatology Association | Journal of Cutaneous Medicine and Surgery, Vol 18, No 2 (March/April), 2014: pp 137–140
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and the patient. Doing so enhances better understanding of the problem and the available therapeutic options. This article describes the surface anatomy of the ear as it relates to locating dermatologic lesions.
Case Report A 73-year-old man was referred for Mohs surgery with a ‘‘lesion on the ear.’’ The history revealed primary surgical
excision for a BCC 4 years previously at the site of concern on the right ear and a thickening of the scarred area over the past year. On examination, there was an eroded, sclerotic plaque located on the tragus and the crux of the helix and extending onto the preauricular skin (Figure 1). The external auditory meatus (EAM) was stenotic, and it was not possible to see the clinical margins of the tumor within the EAM. Based on this examination and the history, we suspected progression of the BCC into the
Figure 3. Subunits of the ear. A, Lateral view. B, Posterior view.
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Canadian Dermatology Association | Journal of Cutaneous Medicine and Surgery, Vol 18, No 2 (March/April), 2014: pp 137–140
Surface Anatomy of the Ear
Table 1. Anatomic Terminology Related to the Surface of the Ear. Anatomy Earlobe (lobule) Helix
Antihelix Crus of the antihelix Scapha Tragus
Antitragus Concha
External auditory meatus (EAM) Pinna Darwin tubercle
Retroauricular sulcus Preauricular cheek Mastoid process
Intertragal notch/incisure
Description Soft, pendulous inferior part of the external ear Curved cresenteric rim of skin and cartilage that shapes the posterior and superior external ear. Anteriorly/medially attaches at the base of the conchal bowl, bisecting the bowl into the cymbal and caval portions. It runs anteriorly/superiorly along the preauricular cheek and traces a circular pathway posteriorly and then inferiorly that ends in its joining with the earlobe. Prominent convex cresenteric fold of skin and cartilage just anterior and parallel to the outer rim (helix) of the external ear Two-pronged anterior aspect of the antihelix, which surrounds the triangular fossa Crescentic depression running between the helix and the antihelix Projection of skin-covered cartilage anterior to the external auditory meatus (EAM). The name is derived from the Greek word for goat, tragos, due to the frequent presence of a tuft of hair on its underside, which resembles a goat’s beard Projection of skin-covered cartilage across the EAM from the tragus. Located between the lobule and the inferior border of the antitragus. Flat or bowl-shaped portion next to and just posterior to the external auditory meatus and anterior to the antihelix. The upper cymba is separated from the lower cavum by the crus of the helix. Hollow, skin-lined tube connecting the external ear to the middle ear The entire visible outer ear. Also referred to as the auricle. A small nodular projection located on the helix at the junction of the upper and middle thirds of the helix. It typically points anteriorly and is present in approximately 10 to 60% of the population. Posterior, crescentic linear depression that forms the fusion of the ear to the postauricular head and neck anterior to the mastoid process The lateral portion of the cheek that is located just anterior to pinna Skin-covered projection of the mastoid portion of the temporal bone. Derived from the Greek word for breast. A point of attachment for several muscles, most notably the sternocleidomastoid. The semicircular notch between the tragus and the antitragus.
See also Figure 3.
EAM and became concerned about the surgical approach and possibility of widespread EAM involvement. We delayed the patient’s Mohs surgery until we could obtain an opinion from our colleagues in Otolaryngology-Head and Neck Surgery. Otolaryngology noted no obvious medial canal or middle ear involvement but agreed to be available in case surgical margins proved otherwise. Mohs surgery proceeded, and the defect following tumor extirpation confirmed sclerosing BCC involvement of the tragus, preauricle, crux of the helix, conchal cavum, antitragus, lobule, and extension into the EAM of approximately 1 cm (Figure 2). The medial ear canal was uninvolved. Reconstruction was accomplished by the Mohs surgery team and included advancement of the cheek to the medial helical margin and full-thickness skin grafting of the remaining defect. Expandable packing was inserted into the EAM for 1 week along with a bolster dressing to prevent the recurrence of stenosis.
Discussion The head and neck represent a very important site of tumor occurrence. In addition to being the most common site for NMSC,5 the anatomy, including the ear, is at a significant risk for recurrence and metastasis.8 This appears to be the case even after Mohs surgery.5 Subsites within the ear may be of significant clinical importance, with recent findings showing that the helix has a higher chance of harboring more aggressive and invasive SCC.5 Recognition of auricular subsites, as illustrated in Figure 3 and described in Table 1, may guide risk stratification for tumor progression and surgical complexity. The ear is one of the high-risk areas for metastasis from SCC.9 Involvement of the external auditory meatus, which may be present in up to one-third of patients with an NMSC on the auricle, carries a worse prognosis.10 This significance is compounded when patients are referred without a biopsy-proven diagnosis.11
Canadian Dermatology Association | Journal of Cutaneous Medicine and Surgery, Vol 18, No 2 (March/April), 2014: pp 137–140
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Sajic et al
In addition to its prognostic implications, the anatomy of the ear, with its highly contoured shape, can present an operative challenge, in terms of both excision and repair. Small lesions at anatomically and/or cosmetically important sites can lead to significant morbidity and surgical complexity. Precise knowledge of the location, and its associated clinical outcomes, would alert the surgeon to a difficult repair after tumor extirpation and aid in the triaging of patients for surgery.
Acknowledgment Financial disclosure of authors and reviewers: None reported.
References 1. Manton K, Akushevich I, Kravchenko J. Chapter 6. In: Krickeberg GM, Samet K, Tsiatis A, Wong W, editors. Cancer mortality and morbidity patterns in the US population: an interdisciplinary approach. 1st ed. New York: Springer; 2009. p. 217–46. 2. Canadian Cancer Society’s Advisory Committee on Cancer Statistics. Canadian cancer statistics 2013. Toronto, ON: Canadian Cancer Society; 2013. Available at: http://www.cancer.ca/,/media/cancer.ca/ CW/cancer%20information/cancer%20101/Canadian%20cancer% 20statistics/canadian-cancer-statistics-2013-EN.pdf.
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3. John Chen G, Yelverton CB, Polisetty SS, et al. Treatment patterns and cost of nonmelanoma skin cancer management. Dermatol Surg 2006;32:1266–71, doi:10.1111/j.1524-4725.2006.32288.x. 4. Rogers HW, Weinstock MA, Harris AR, et al. Incidence estimate of nonmelanoma skin cancer in the United States, 2006. Arch Dermatol 2010;146:283–7, doi:10.1001/archdermatol.2010.19. 5. Ragi JM, Patel D, Masud A, Rao BK. Nonmelanoma skin cancer of the ear: frequency, patients’ knowledge, and photoprotection practices. Dermatol Surg 2010;36:1232–9, doi:10.1111/j.1524-4725. 2010.01615.x. 6. McGuire JF, Ge NN, Dyson S. Nonmelanoma skin cancer of the head and neck I: histopathology and clinical behavior. Am J Otolaryngol 2009;30:121–33, doi:10.1016/j.amjoto.2008.03.002. 7. Ridky TW. Nonmelanoma skin cancer. J Am Acad Dermatol 2007; 57:484–501, doi:10.1016/j.jaad.2007.01.033. 8. Duffy KL, McKenna JK, Hadley ML, Tristani-Firouzi P. Nonmelanoma skin cancers of the ear: correlation between subanatomic location and post-Mohs micrographic surgery defect size. Dermatol Surg 2009;35:30–3, doi:10.1111/j.1524-4725.2008.34379.x. 9. Veness MJ. Defining patients with high-risk cutaneous squamous cell carcinoma. Australas J Dermatol 2006;47:28–33, doi:10.1111/ j.1440-0960.2006.00218.x. 10. Massey RA, Eliezri YD. Partial auriculotomy for exposure of tumors of the external auditory meatus and conchal bowl. Arch Dermatol 1998;134:13–5, doi:10.1001/archderm.134.1.13. 11. Bowne WB, Antonescu CR, Leung DH, et al. Dermatofibrosarcoma protuberans: a clinicopathologic analysis of patients treated and followed at a single institution. Cancer 2000;88:2711–20, doi:10.1002/ 1097-0142(20000615)88:12,2711::AID-CNCR9.3.0.CO;2-M.
Canadian Dermatology Association | Journal of Cutaneous Medicine and Surgery, Vol 18, No 2 (March/April), 2014: pp 137–140
Surface Anatomy of the Ear Dusan Sajic, Jason Archibald, and Christian Murray Expert diagnosis of cutaneous pathology requires precise anatomic description. This brief report will review the clinically relevant surface anatomy of the ear. Bien connaıˆtre l’anatomie de l’oreille a des incidences sur le plan clinique en ce qui concerne l’e´volution des cancers de la peau sie´geant en des points particuliers et la complexite´ de la reconstruction chirurgicale. Le cas pre´sente´ ici et l’examen de l’anatomie de la surface de l’oreille aideront les cliniciens a` repe´rer ces points particuliers.
ONMELANOMA SKIN CANCER (NMSC) is the most common type of human cancer.1,2 It accounts for over 1 million new cases in the United States every year3,4 and over 80,000 new cases in Canada, more than cancers of the lung, colorectum, and breast combined.2 Although NMSC generally carries an excellent prognosis, with a very low mortality rate,5 several factors have important prognostic implications. These include the tumor size and type, immune status of the patient, and anatomic location of the lesion. Each of these can increase the burden of disease and necessitate more complicated treatment modalities.6 The two most common tumor types include basal cell carcinoma (BCC) and squamous cell carcinoma (SCC), with the former being approximately four to five times more common.7 The anatomy of the ear, with its highly contoured and richly vascularized architecture, represents a significant challenge for both tumor excision and repair. Specific anatomic subunits carry a worse prognosis in terms of both tumor recurrence, growth, or metastasis and cosmetic outcomes. An accurate dermatologic diagnosis, with precise anatomic terminology, greatly assists in the communication between the referring doctor, the surgeon,
N
Figure 1. Patient referred with a lesion on the right ear.
From the Division of Dermatology, University of Toronto, Toronto, ON, and the Division of Otolaryngology, McMaster University, Hamilton, Ontario. Address reprint requests to: Christian Murray, Division of Dermatology, University of Toronto, Women’s College Hospital, 76 Grenville Street, Toronto, ON M5S 1B2.
DOI 10.2310/7750.2013.13057 # 2014 Canadian Dermatology Association
Figure 2. Defect post–Mohs surgery for sclerosing basal cell carcinoma.
Canadian Dermatology Association | Journal of Cutaneous Medicine and Surgery, Vol 18, No 2 (March/April), 2014: pp 137–140
137
Sajic et al
and the patient. Doing so enhances better understanding of the problem and the available therapeutic options. This article describes the surface anatomy of the ear as it relates to locating dermatologic lesions.
Case Report A 73-year-old man was referred for Mohs surgery with a ‘‘lesion on the ear.’’ The history revealed primary surgical
excision for a BCC 4 years previously at the site of concern on the right ear and a thickening of the scarred area over the past year. On examination, there was an eroded, sclerotic plaque located on the tragus and the crux of the helix and extending onto the preauricular skin (Figure 1). The external auditory meatus (EAM) was stenotic, and it was not possible to see the clinical margins of the tumor within the EAM. Based on this examination and the history, we suspected progression of the BCC into the
Figure 3. Subunits of the ear. A, Lateral view. B, Posterior view.
138
Canadian Dermatology Association | Journal of Cutaneous Medicine and Surgery, Vol 18, No 2 (March/April), 2014: pp 137–140
Surface Anatomy of the Ear
Table 1. Anatomic Terminology Related to the Surface of the Ear. Anatomy Earlobe (lobule) Helix
Antihelix Crus of the antihelix Scapha Tragus
Antitragus Concha
External auditory meatus (EAM) Pinna Darwin tubercle
Retroauricular sulcus Preauricular cheek Mastoid process
Intertragal notch/incisure
Description Soft, pendulous inferior part of the external ear Curved cresenteric rim of skin and cartilage that shapes the posterior and superior external ear. Anteriorly/medially attaches at the base of the conchal bowl, bisecting the bowl into the cymbal and caval portions. It runs anteriorly/superiorly along the preauricular cheek and traces a circular pathway posteriorly and then inferiorly that ends in its joining with the earlobe. Prominent convex cresenteric fold of skin and cartilage just anterior and parallel to the outer rim (helix) of the external ear Two-pronged anterior aspect of the antihelix, which surrounds the triangular fossa Crescentic depression running between the helix and the antihelix Projection of skin-covered cartilage anterior to the external auditory meatus (EAM). The name is derived from the Greek word for goat, tragos, due to the frequent presence of a tuft of hair on its underside, which resembles a goat’s beard Projection of skin-covered cartilage across the EAM from the tragus. Located between the lobule and the inferior border of the antitragus. Flat or bowl-shaped portion next to and just posterior to the external auditory meatus and anterior to the antihelix. The upper cymba is separated from the lower cavum by the crus of the helix. Hollow, skin-lined tube connecting the external ear to the middle ear The entire visible outer ear. Also referred to as the auricle. A small nodular projection located on the helix at the junction of the upper and middle thirds of the helix. It typically points anteriorly and is present in approximately 10 to 60% of the population. Posterior, crescentic linear depression that forms the fusion of the ear to the postauricular head and neck anterior to the mastoid process The lateral portion of the cheek that is located just anterior to pinna Skin-covered projection of the mastoid portion of the temporal bone. Derived from the Greek word for breast. A point of attachment for several muscles, most notably the sternocleidomastoid. The semicircular notch between the tragus and the antitragus.
See also Figure 3.
EAM and became concerned about the surgical approach and possibility of widespread EAM involvement. We delayed the patient’s Mohs surgery until we could obtain an opinion from our colleagues in Otolaryngology-Head and Neck Surgery. Otolaryngology noted no obvious medial canal or middle ear involvement but agreed to be available in case surgical margins proved otherwise. Mohs surgery proceeded, and the defect following tumor extirpation confirmed sclerosing BCC involvement of the tragus, preauricle, crux of the helix, conchal cavum, antitragus, lobule, and extension into the EAM of approximately 1 cm (Figure 2). The medial ear canal was uninvolved. Reconstruction was accomplished by the Mohs surgery team and included advancement of the cheek to the medial helical margin and full-thickness skin grafting of the remaining defect. Expandable packing was inserted into the EAM for 1 week along with a bolster dressing to prevent the recurrence of stenosis.
Discussion The head and neck represent a very important site of tumor occurrence. In addition to being the most common site for NMSC,5 the anatomy, including the ear, is at a significant risk for recurrence and metastasis.8 This appears to be the case even after Mohs surgery.5 Subsites within the ear may be of significant clinical importance, with recent findings showing that the helix has a higher chance of harboring more aggressive and invasive SCC.5 Recognition of auricular subsites, as illustrated in Figure 3 and described in Table 1, may guide risk stratification for tumor progression and surgical complexity. The ear is one of the high-risk areas for metastasis from SCC.9 Involvement of the external auditory meatus, which may be present in up to one-third of patients with an NMSC on the auricle, carries a worse prognosis.10 This significance is compounded when patients are referred without a biopsy-proven diagnosis.11
Canadian Dermatology Association | Journal of Cutaneous Medicine and Surgery, Vol 18, No 2 (March/April), 2014: pp 137–140
139
Sajic et al
In addition to its prognostic implications, the anatomy of the ear, with its highly contoured shape, can present an operative challenge, in terms of both excision and repair. Small lesions at anatomically and/or cosmetically important sites can lead to significant morbidity and surgical complexity. Precise knowledge of the location, and its associated clinical outcomes, would alert the surgeon to a difficult repair after tumor extirpation and aid in the triaging of patients for surgery.
Acknowledgment Financial disclosure of authors and reviewers: None reported.
References 1. Manton K, Akushevich I, Kravchenko J. Chapter 6. In: Krickeberg GM, Samet K, Tsiatis A, Wong W, editors. Cancer mortality and morbidity patterns in the US population: an interdisciplinary approach. 1st ed. New York: Springer; 2009. p. 217–46. 2. Canadian Cancer Society’s Advisory Committee on Cancer Statistics. Canadian cancer statistics 2013. Toronto, ON: Canadian Cancer Society; 2013. Available at: http://www.cancer.ca/,/media/cancer.ca/ CW/cancer%20information/cancer%20101/Canadian%20cancer% 20statistics/canadian-cancer-statistics-2013-EN.pdf.
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3. John Chen G, Yelverton CB, Polisetty SS, et al. Treatment patterns and cost of nonmelanoma skin cancer management. Dermatol Surg 2006;32:1266–71, doi:10.1111/j.1524-4725.2006.32288.x. 4. Rogers HW, Weinstock MA, Harris AR, et al. Incidence estimate of nonmelanoma skin cancer in the United States, 2006. Arch Dermatol 2010;146:283–7, doi:10.1001/archdermatol.2010.19. 5. Ragi JM, Patel D, Masud A, Rao BK. Nonmelanoma skin cancer of the ear: frequency, patients’ knowledge, and photoprotection practices. Dermatol Surg 2010;36:1232–9, doi:10.1111/j.1524-4725. 2010.01615.x. 6. McGuire JF, Ge NN, Dyson S. Nonmelanoma skin cancer of the head and neck I: histopathology and clinical behavior. Am J Otolaryngol 2009;30:121–33, doi:10.1016/j.amjoto.2008.03.002. 7. Ridky TW. Nonmelanoma skin cancer. J Am Acad Dermatol 2007; 57:484–501, doi:10.1016/j.jaad.2007.01.033. 8. Duffy KL, McKenna JK, Hadley ML, Tristani-Firouzi P. Nonmelanoma skin cancers of the ear: correlation between subanatomic location and post-Mohs micrographic surgery defect size. Dermatol Surg 2009;35:30–3, doi:10.1111/j.1524-4725.2008.34379.x. 9. Veness MJ. Defining patients with high-risk cutaneous squamous cell carcinoma. Australas J Dermatol 2006;47:28–33, doi:10.1111/ j.1440-0960.2006.00218.x. 10. Massey RA, Eliezri YD. Partial auriculotomy for exposure of tumors of the external auditory meatus and conchal bowl. Arch Dermatol 1998;134:13–5, doi:10.1001/archderm.134.1.13. 11. Bowne WB, Antonescu CR, Leung DH, et al. Dermatofibrosarcoma protuberans: a clinicopathologic analysis of patients treated and followed at a single institution. Cancer 2000;88:2711–20, doi:10.1002/ 1097-0142(20000615)88:12,2711::AID-CNCR9.3.0.CO;2-M.
Canadian Dermatology Association | Journal of Cutaneous Medicine and Surgery, Vol 18, No 2 (March/April), 2014: pp 137–140
