Auricular anatomy and analysis — The measurements that localise the defect
The subunits and where they hide scars, the anthropometry that defines normality, the three angles that decide whether an ear is prominent, the anatomical causes of prominence and the catalogue of auricular deformities.
Content intended for healthcare professionals. It does not replace clinical assessment and is not written as patient information.
Key points
- The ear is a single plate of elastic cartilage 0.5 to 1 mm thick folded on itself. Almost all aesthetic pathology reduces to a fold that is missing or an angle that is excessive.
- Incisions placed at the junctions between subunits on the anterior surface produce virtually imperceptible scars. That is why design matters more than technique.
- The deciding angle is the auriculocephalic one: 97 % of ears fall between 25° and 35°, and above 40-45° an ear is perceived as prominent.
- Prominence almost never has a single cause: an unfurled antihelix, a hypertrophic concha and an obtuse scaphaconchal angle usually coexist, and all three must be quantified separately.
- The goal is not a perfect ear but a normal-looking ear in which the surgery does not show. Sharp contours, overcorrection and visible scars are not acceptable results.
A cartilage that behaves differently
The auricle consists of thin, tightly adherent anterior skin, thicker, loosely attached posterior skin with a little areolar tissue in between, and between them a single plate of elastic cartilage invested in perichondrium. Only the lobule lacks cartilage: it is fibrofatty tissue hanging below the framework. That elastic cartilage — the same as in the auditory canal, the eustachian tube and the supraglottic larynx — shares type II collagen with hyaline cartilage but adds a dense network of finely branched elastic fibres, hence its characteristic flexibility. Two practical consequences. First: cartilage has no vessels or nerves and is nourished by diffusion, which together with its dense matrix makes it poorly antigenic and almost ideal as transplant material. Second, less pleasant: the chondrogenic activity of the perichondrium is limited to the growth period, so injury in the adult fills with fibrous tissue, not cartilage.
The perichondrium explains cauliflower ear
A haematoma separating cartilage from its nutrient supply produces, in the potential space created, fibrous tissue that can be very dense, and cicatricial retraction of the perichondrium itself distorts the contour. Since the perichondrium is firmly adherent anteriorly and loose posteriorly, the deformity affects almost exclusively the anterior contour: the classic cauliflower ear. The same anatomy explains why early drainage and a properly applied compressive dressing are not a postoperative detail but the manoeuvre that prevents the sequela. It also explains why the framework becomes less resilient with age: chondrocytes atrophy, water content falls and cavities appear that calcify. The surgical reading is direct: in the older patient, cartilage manoeuvres must be more decisive to achieve and hold the change.
The subunits and what each contributes
| Subunit | What it is | Why it matters in theatre |
|---|---|---|
| Helix | The rolled rim that starts above the meatus as the helical crus and descends in an arc to the cauda | It is the line the eye follows. Any notch in its edge betrays surgery, and an insufficient roll makes the ear look flat |
| Antihelix | The second arc: it begins at the antitragus and divides into a wide superior crus and a sharper inferior crus, with the triangular fossa between them | Its lack of fold is the commonest cause of a prominent ear. And one non-negotiable rule: it must never be the most lateral structure on frontal view |
| Concha | The bowl at the canal entrance, divided by the helical root into cavum below and cymba above. Mean depth under 1.5 cm | Its vertical wall acts as a buttress for the rest of the auricle. When it is tall, the middle third of the helix protrudes |
| Scapha | The deep groove between the helical rim and the superior aspect of the antihelix | It is where the excess sits when the ear is large, and the donor zone for most cartilage resections |
| Tragus and antitragus | They should project laterally about 1 cm from the depth of the conchal bowl | They are the reference for conchal depth and the antitragus, with the cauda, determines lobule position |
| Lobule | Fibrofatty tissue without cartilage. Round, flat or triangular, and pendulous or non-pendulous depending on attachment to the cheek | It gets forgotten and ruins results: it must lie within the plane of the scapha. Non-pendulous lobules are more symmetrical, shorter and elongate less over the years |
The measurements to keep in mind
- A proportionate ear is 40-50 % longer than wide: mean length 5.5 to 7 cm and width 3 to 4.5 cm.
- It divides into thirds that contribute unequally to length: superior 33 %, middle 44 %, inferior 23 %. Knowing this is what allows the excess to be localised in a large ear.
- The ear axis is posteriorly inclined by about 20° and its superior pole sits at brow level. Face and ear are read together: aesthetically there is macrotia when the auricle exceeds the limits of the middle facial third, even if absolute figures are normal.
- Growth: 85 % of adult size by age 3, reaching 100 % in width at 6-7 years and in length at 12-13. This is the datum behind the usual surgical timing.
- And one asymmetry worth documenting before operating, not after: published series describe scaphal size asymmetry in around 15 % of patients and differences in ear height in around 11 %.
The angles, and what each one corrects
| Angle | How it is measured | Normal value and meaning |
|---|---|---|
| Auriculocephalic | Between the tangent to the parietal scalp and the line through the most posterior point of the scapha | 25-35° in 97 % of ears. Above 40-45° it reads as prominent. It is the global angle, the sum of the other two |
| Cephaloconchal | Between the tangent to the scalp and the line through the most posterior point of the concha | Ideally greater than 45°. When it is closed, the problem is the concha and the corrective manoeuvre addresses it: setback or reduction of the vertical wall |
| Scaphaconchal | Vertex at the antihelix, between the line to the most posterior conchal point and that to the most posterior scaphal point | Ideally no greater than 90°, so the triangular fossa faces laterally rather than anteriorly. If obtuse, the problem is the antihelix |
| Conchomastoid | Between the conchal plane and the mastoid surface | Around 25° in men and 20° in women. Increased in prominent ears: it is the angle conchomastoid sutures act upon |
The helix-to-scalp distance, and the error of overdoing it
The helical rim should project symmetrically about 10-12 mm from the scalp at the upper helix, increasing progressively to 15-20 mm at the cauda. The point of maximum protrusion lies somewhere between the superior pole and mid-auricle, not at the pole. And here lies otoplasty’s commonest error: if that distance is reduced below 10 mm, the ear takes on a stuck-down appearance, more telling than the original prominence. On frontal view the upper third of the helix should be visible 2-5 mm lateral to the antihelix; a relative protrusion of the middle third is aesthetically acceptable, as is slight lobular protrusion, provided it stays within the plane of the scapha.
The three causes of prominence
The prominent ear affects around 5 % of the population and is probably the commonest congenital deformity of the head and neck — in contrast to microtia, whose incidence approaches 1:20,000. The commonest abnormality is an insufficiently furled antihelix, especially its superior crus: the concha flows directly into the scapha without a clear line of demarcation, the scaphaconchal angle loses acuity and the upper third appears flattened, lengthened and disproportionate. The second is a misshapen concha with a high vertical wall, which makes the middle third of the helix protrude. A classic series attributed two thirds of cases to an obtuse scaphaconchal angle and one third to the concha, but in practice what is seen is that nearly 90 % of patients have both. The third, less common, is underdevelopment of the inferior crus of the antihelix, which protrudes the superior pole. To this is often added protrusion of the lobule, which aggravates the overall perception even when it is not the cause.
The catalogue of deformities
| Deformity | What fails | Surgical implication |
|---|---|---|
| Prominent ear | Unfurled antihelix, excessive conchal height or lateral angulation. Normal size and shape | The standard case. Corrected by creating the fold and adjusting the concha, and often the lobule too because of cauda protrusion |
| Lop ear | Incomplete maturation of antihelix, scapha and helix: the upper pole hangs with an acute downward fold | Usually accompanied by poorly resilient cartilage, which worsens the problem and limits suture-only techniques |
| Cup ear | An overdeveloped, deeply concave concha, with a concentrically cupped appearance and reduced total height | The cartilage is usually thick, which makes lasting correction distinctly harder than in the lop ear |
| Shell ear | Absent helical rim roll, sometimes with an obtuse angle of the helical root against the scalp | It gives a flattened upper and middle third. Creating the antihelical fold is not enough: the rim itself must be addressed |
| Satyr and Machiavellian ear | Incomplete furling leaving a pointed helical contour; the Machiavellian adds a large, flattened scapha with thin cartilage | The Machiavellian form may be associated with true macrotia, the ear enlarged in all dimensions |
| Stahl’s ear | Presence of a third transverse antihelical crus, posterior to the usual two | It is not solved by standard manoeuvres: the supernumerary crus must be addressed in addition to the rest |
| Macrotia | An auricle exceeding normative data in length or width. The excess sits above all in the upper third, at the scapha | It frequently coexists with prominence, because an unfurled antihelix widens the scapha and enlarges the auricle. Treat both or the result is half done |
Blood supply, innervation and their implications
- Arterial supply comes from the external carotid via the superficial temporal and posterior auricular arteries, with a contribution from the occipital. The network is so redundant that dividing one vessel does not compromise viability, and that is precisely what has allowed cartilage-cutting techniques of every kind to flourish.
- Sensation comes from the C2 and C3 roots of the cervical plexus: the great auricular nerve covers much of the anterior surface and the lesser occipital the posterior. The auriculotemporal (V3) contributes at the helical root and tragus, as does the auricular branch of the vagus, Arnold’s nerve.
- That distribution is what makes a perimeatal ring block possible for surgery under local anaesthesia, and also what explains the persistently less anaesthetised anterior zone if the auriculotemporal block is not completed.
- Auricular stability rests on three extrinsic ligaments: an anterior one from the zygomatic root to tragus and helical spine, a posterior one from the mastoid to the conchal wall, and one bridging the canal from tragus to helix. If the posterior one fails or is injured, the unstable or "flop" ear appears.
Examination: localise the defect before choosing a technique
Does the scaphaconchal angle exceed 90°?
Is the cephaloconchal angle below 45° or the concha deeper than 1.5 cm?
Is anything still prominent after mentally correcting the above?
References
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- 2.Wright WK. Otoplasty goals and principles. Arch Otolaryngol. 1970;92(6):568-572.
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- 4.Ohlsén L, Vedung S. Reconstructing the antihelix of protruding ears by perichondrioplasty. Plast Reconstr Surg. 1980;65(6):753-762.
- 5.Azaria R, Adler N, Silfen R, Regev D, Hauben DJ. Morphometry of the adult human earlobe: a study of 547 subjects and clinical application. Plast Reconstr Surg. 2003;111(7):2398-2402.
- 6.Janis JE, Rohrich RJ, Gutowski KA. Otoplasty. Plast Reconstr Surg. 2005;115(4):60e-72e.
- 7.Thorne CH, Wilkes G. Ear deformities, otoplasty, and ear reconstruction. Plast Reconstr Surg. 2012;129(4):701e-716e.
- 8.Pawar SS, Koch CA, Murakami C. Treatment of prominent ears and otoplasty: a contemporary review. JAMA Facial Plast Surg. 2015;17(6):449-454.
- 9.Adamson PA, Litner JA, Thomas JR. Aesthetic Otoplasty. Shelton: People’s Medical Publishing House; 2011.
- 10.Tracy JC, Lee AS, Scott AR, eds. Advanced Cosmetic Otoplasty: Art, Science, and New Clinical Techniques. Berlin: Springer; 2013.
Related specialty: Facial Aesthetic Surgery