The auricle (or pinna, pinna of ear, auricle of ear, auricula, latin: auricula) is the external, visible component of the ear around the outer opening of the ear canal. The main function of the auricle is to collect, amplify and direct sound waves into the external auditory canal.
Structure of auricle
The characteristic shape of the auricle is determined by elastic cartilage forming a structural framework of the auricle, called the auricular cartilage. The auricle is comprised of the following anatomical features:
The helix is the external, curved margin of the auricle. The crus of the helix is the site of origin of the helix situated in the cavity (concha) of the auricle. The spine of the helix is a small cartilaginous prominence projecting forward from the crus. The tail of the helix is the posterior, inferior end of the helix separated from the antihelix by an indentation.
The antihelix is an arched projection seen on the auricle situated in front of the posterior part of the helix. The triangular fossa (or fossa triangularis) is an anterosuperiorly located fossa enclosed by the two crura of the antihelix. The crura of the antihelix are formed by a bifurcation of the antihelix superiorly.
The scapha (or scaphoid fossa) is a fossa located posteriorly between the helix and antihelix.
The concha of the auricle is a cavity of the auricle enclosed by the antihelix, antitragus and tragus. The cymba conchae of the auricle is the upper, slit-like part of the concha between the crura of the helix and antihelix. The cavity of the concha of the auricle is the main part of the concha located below the crus of the helix and behind the tragus.
The tragus is a flat projection in front of the external acoustic opening.
The antitragus is a small tubercle situated on the inferior continuation of the antihelix and separated from the tragus by the intertragic notch.
The intertragic notch (also called intertragic incisure or intertragal incisure) is a notch between the tragus and antitragus.
The lobule of the auricle (also known as ear lobe) is the lower end of the auricle that does not have cartilage.
Innervation and blood supply of auricle
The sensory innervation of the auricle is provided by the great auricular nerve (originating from cervical plexus) supplying the helix, antihelix and lobule of the auricle; the lesser occipital nerve (also from cervical plexus) supplying the superior part of the cranial surface of the auricle; the auriculotemporal nerve (a branch of the mandibular nerve) innervating the tragus, the crus and the adjacent part of the helix; and the auricular branch of the vagus nerve (CN X) together with the facial nerve (CN VII) supplying small areas of the auricle, innervating the concha, as well as the posterior and superior parts of the eminentia of the concha, which is present on the posterior surface of the auricle.
The posterior and anterior auricular arteries arising from the external carotid artery provide blood supply to the auricle.