Auricle (anatomy)

Auricle
The auricula. Lateral surface.
Details
Artery	posterior auricular, anterior auricular
Nerve	Trigeminal nerve, Great auricular nerve, Lesser occipital nerve
Lymph	To Pre & Post Auricular Nodes, Nodes of Parotid and Cervical Chains
Identifiers
Latin	auricula
TA	A15.3.01.002
FMA	56580
Anatomical terminology []

The auricle or auricula is the visible part of the ear that resides outside of the head. It is also called the pinna (Latin for wing / fin, plural pinnae), a term that is used more in zootomy.

The diagram shows the shape and location of most of these components:

The developing auricle is first noticeable around the sixth week of gestation in the human fetus, developing from the auricular hillocks, which are derived from the first and second pharyngeal arches. These hillocks develop into the folds of the auricle and gradually shift upwards and backwards to their final position on the head. En route accessory auricles (also known as preauricular tags) may be left behind. The first three hillocks are derived from the 1st branchial arch and form the tragus, crus of the helix, and helix, respectively. Cutaneous sensation to these areas is via the trigeminal nerve, the attendant nerve of the 1st branchial arch. The final three hillocks are derived from the second branchial arch and form the antihelix, antitragus, and lobule, respectively. These portions of the ear are supplied by the cervical plexus and a small portion by the facial nerve. This explains why vesicles are classically seen on the auricle in herpes infections of the facial nerve (Ramsay Hunt syndrome type II).

The auricle functions to collect sound and transform it to directional and other information. The auricle collects sound and acting as a funnel, amplifies the sound and directs it to the auditory canal. The filtering effect of the human pinna preferentially selects sounds in the frequency range of human speech.

Amplification of sound by the pinna, tympanic membrane and middle ear causes an increase in level of about 10 to 15 dB in a frequency range of 1.5 kHz to 7 kHz. This amplification is an important factor in inner ear trauma resulting from elevated sound levels.