The Ear

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Chapter 5 The Ear

A. External Ear

6 What is the auricle (or pinna)?

It is the part of the external ear that is outside the canal (Fig. 5-1). Made of cartilage and skin, it is highly flexible.

image

Figure 5-1 Anatomy of the external auditory meatus.

(From Granger N: Crash Course Anatomy. St. Louis, Mosby, 2007.)

7 What are auricular bumps? What causes them?

Auricular papules or nodules are common. Most are benign, but some represent early neoplasms or clues to underlying systemic disorders. Specific etiologies include:

image Darwin’s tubercle (Fig. 5-2): Benign and congenital nodule near the auricular apex (on the helix, at the junction of upper and middle thirds). Nontender and rarely bilateral, it was first described by the British sculptor Thomas Woolner, a founding member of the Pre-Raphaelite Brotherhood and a spare-time anatomist. Woolner depicted it in his statue of “Puck,” and Charles Darwin was so impressed that he named it the Woolnerian tip. It is an atavistic feature (i.e., a trait typical of our mammalian ancestors—more specifically, monkeys).

image Keloids (Fig. 5-3): Smooth and flesh-colored papule(s) on one or both sides of the earlobe. They indicate an exuberant and fibrotic response to injury.

image Tophi: One or more nontender nodules on the auricular edges. They are named after the Latin tufa (a calcareous and volcanic deposit) and may indeed be mildly hard. They can occur on both helix and antihelix, and usually indicate hyperuricemia and gout.

image Chondrodermatitis nodularis chronica helicis (CNH): This is a common, benign, and painful condition of the most prominent projection of the ear, usually the apex of the helix, but it also may affect the antihelix. It is typical of the right ear of middle-aged to older men, usually fair-skinned individuals with cutaneous sun-damage. In 10–35% of cases, it may also affect women. It is rather common (in a series, the most frequent external ear condition seen in an ear-nose-throat clinic) and is probably due to prolonged and excessive pressure, leading to inflammation, edema, and ischemic necrosis. This eventually degenerates into secondary perichondritis due to the vascular characteristics of the ear. Onset may be precipitated by pressure, trauma, or cold. Sleeping on the affected side is also common. The nodule appears spontaneously and painfully, rapidly enlarging to a maximum size of 4–8   mm, after which it remains stable. It is firm, tender, skin-colored, sharply demarcated, and round to oval in shape. The edge is usually raised, with a central ulcer or crust. It is not associated with systemic disorders.

image

Figure 5-2 Darwin’s tubercle (left) and tophi (right).

(From Seidel HM, Ball JW, Daims JE, Benedict GW: Mosby’s Guide to Physical Examination, 3rd ed. St. Louis, Mosby, 1995.)

image

Figure 5-3 Keloids of the earlobe.

(From Fitzpatrick JE, Aeling H: Dermatology Secrets. Philadelphia, Hanley & Belfus, 1996.)