What is the auricle or pinna?

The only visible part of the ear: the pinna

The pinna is the outer part of the ear, located on the sides of the head around the opening of the external auditory canal. It has a distinctive shape, characterised by various regions, and is made of cartilage covered by skin tissue. The auricle plays a very important role as it receives and decodes sounds, enabling us to hear.

The anatomy of the auricle or pinna

The auricle, in terms of anatomy, is part of the so-called external ear, which is the outermost part of the ear. The external ear consists of the auricle or pinna and the external auditory canal. The auricle acts as a large funnel that collects sounds and directs them towards the middle and inner ear. The auricle is made of elastic cartilage covered by a thin layer of skin, muscles, and ligaments. Let’s examine its structure.

Cartilage

The pinna is characterised by its cartilaginous component and a series of prominences, which are:

  • The helix, the outer rim of the ear, curves outward from the ear and terminates at the inferior part of the lobe.
  • The antihelix, the arcuate part of the auricle, is separated from the helix by a groove called the scaphoid fossa.
  • The scaphoid fossa, the groove in the auricle located between the helix and the antihelix.
  • The concha, the concave area of the auricle enclosed by the antihelix, tragus, and antitragus, which funnels into the opening of the external auditory canal.
  • The tragus, the flattened, triangular prominence that overlooks the entrance of the external auditory canal.
  • The antitragus, the small triangular prominence located below the antihelix and behind the tragus.
  • The intertragic notch, the part of the auricle that separates the tragus from the antitragus.
  • The earlobe, the lower extremity of the auricle made up of fatty tissue.

Muscles

The muscles of the auricle correspond to the muscles of the external ear and are as follows:

  • The great auricular muscle, a narrow vertical strip located on the anterior edge of the helix.
  • The small auricular muscle, a small oblique band covering the crus of the helix.
  • The muscle of the tragus, a flat, short vertical band located on the lateral surface of the tragus.
  • The muscle of the antitragus, extending from the outer part of the antitragus to an area between the helix and the antihelix.
  • The transverse auricular muscle, stretching from the concha to the scaphoid fossa.
  • The oblique auricular muscle, running from the postero-superior part of the concha to the convex area above it.

Ligaments

The ligaments of the auricle are of two types:

  • Intrinsic ligaments, which primarily serve to maintain the shape of the auricle.
  • Extrinsic ligaments, which connect the auricle to the temporal bone.

The function of the auricle

The auricle or pinna has an auditory function as it is involved in the perception of sound. The auricle is capable of locating, capturing, and directing acoustic signals towards the external auditory canal, which then transmits them to the middle ear. Additionally, the auricle can amplify sound waves with frequencies around 3,000 Hz.

A woman with her left hand resting on the headphones during a hearing test

Try our online hearing test

Take a quick, easy test to find out how you're hearing.

Auricle or pinna: the nerves involved

The auricle or pinna is supplied by several sensory nerves, with the main ones being the trigeminal nerve and the cervical plexus. The trigeminal nerve provides innervation to the tragus and the ascending part of the helix through the auriculotemporal nerve (mandibular branch), which innervates the lateral aspect of the auricle.

The cervical plexus, via the great auricular nerve, innervates the lower two-thirds of both surfaces of the auricle. Additionally, there is the auricular branch of the vagus nerve, also known as the auricular nerve, which innervates the external auditory canal and the concha. The skin of the concha receives sensory fibres from both the vagus and the glossopharyngeal nerves, with the majority coming from the auricular branch of the vagus nerve.

Possible related diseases

The auricle can be subject to both congenital and acquired abnormalities. Congenital abnormalities, such as microtia and atresia, may occur during pregnancy and lead to hearing impairments. Acquired abnormalities, on the other hand, can result from conditions such as auricular perichondritis, burns, or traumatic injuries. Auricular perichondritis is an inflammation of the tissue covering the cartilage of the auricle and can stem from otitis, trauma, dermatitis, perforations, and burns.

Find your nearest clinic in one click

Have a look at out related contents

Learn more on how your hearing works, thanks to our experts contents. You can also have a look at our blog, with our latest news. 

Get support and advice

Book a free hearing test

Book now

Test your hearing online

Take the test

Find your nearest store

Find a store