External ear

The external ear comprises the auricle (or pinna), the external auditory meatus, and the tympanum (eardrum). The pinna concentrates and amplifies sound waves and funnels them through the outer acoustic pore into the external auditory meatus, which carries them to the tympanic membrane.

Gross anatomy

Auricle (pinna)

The auricle is the part of the ear that projects laterally from the head. It is composed of an irregular concave plate of elastic cartilage and dense connective tissue, covered by skin which contains short hairs (tragi), sebaceous glands, and ceruminous glands.

Structure

The auricle has a complex shape that is composed of several ridges, notches, and grooves (see Figure 1):

  • helix: posterior free margin of the auricle
  • anthelix: a ridge parallel to the helix
    • crura anthelicis: a pair of limbs located above the external acoustic pore
    • fossa triangularis: tiny depression between the crura
  • scaphoid fossa: the depression between the helix and anthelix 
  • tragus: prominence in front of the external acoustic pore
    • can be manually pushed back over the pore, to mitigate noise
  • antitragus: situated in the lower part of the anthelix and faces the tragus
  • intertragic incisure: a notch separating the tragus from the antitragus
  • cavum conchae: the deepest depression in the auricle, inferior to the crus of the helix
  • cymba conchae: depression surrounded by the crus of the helix below and the inferior crus of anthelix above
  • ear lobe: the lowest part of the ear and the only part that does not contain cartilage, situated below the intertragic incisure
Vascular supply

The auricle is supplied by

Innervation
External auditory meatus

The external auditory meatus is a short canal leading from the auricle to the tympanic membrane. It is lined by skin containing hair follicles (tragi), sebaceous glands, and ceruminous glands.

Tympanum

The tympanic membrane consists of two layers of collagen fibres:

  • an outer layer with a radial fibre arrangement
  • an inner layer with a circular fibre arrangement

It has an outer cover of extremely thin skin and an inner layer of cuboidal epithelium facing the tympanic cavity.

Head and neck anatomy
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Article information

rID: 1306
System: Head & Neck
Section: Anatomy
Synonyms or Alternate Spellings:
  • auricle
  • pinna

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Cases and figures

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    Figure 1: external ear
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    Figure 2: external ear, surface shaded
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    Figure 3: external ear anatomy (CT)
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