Anatomy of the Auricle
- The auricle is the visible part of the ear outside the head.
- It is also known as the pinna.
- The developing auricle forms from the auricular hillocks derived from the first and second pharyngeal arches.
- Cutaneous sensation to different areas of the auricle is provided by the trigeminal nerve and facial nerve.
- Vesicles on the auricle can be seen in herpes infections of the facial nerve.
Functions of the Auricle
- The auricle collects sound and amplifies it, directing it to the auditory canal.
- It acts as a funnel to collect sound.
- The pinnae have a filtering effect that selects sounds in the frequency range of human speech.
- The auricle helps in sound localization and provides directional information.
- In animals, the pinna collects sound, performs spectral transformations, and aids in vertical sound localization.
Amplification and Modulation
- The pinna, tympanic membrane, and middle ear amplify sound by about 10 to 15dB in the frequency range of 1.5kHz to 7kHz.
- This amplification can cause inner ear trauma at elevated sound levels.
- Non-electrical hearing apparatuses have been studied to protect hearing in loud environments.
- These apparatuses fit snugly in the concha and are designed to protect musicians and others in loud environments.
- The Institute of Sound and Vibration Research (ISVR) at the University of Southampton has studied these apparatuses.
Notch of Pinna
- The pinna has a notch that eliminates a small segment of the frequency spectrum.
- It works differently for low and high frequency sounds.
- For low frequencies, it acts as a reflector dish, directing sounds towards the ear canal.
- For high frequencies, it causes phase cancellation, eliminating certain frequency components.
- The pinna notch typically affects sounds around 10kHz and aids in vertical sound localization.
Additional Information
- Visible auricles are common in mammals, particularly placental mammals and marsupials.
- Marine mammals usually have reduced or no auricles due to sound traveling differently in water.
- External auricles are absent in reptiles, amphibians, and birds.
- Skin impressions show large auricles in certain extinct mammals.
- The pinna can also signal mood and radiate heat in various species.
The auricle or auricula is the visible part of the ear that is outside the head. It is also called the pinna (Latin for 'wing' or 'fin', pl.: pinnae), a term that is used more in zoology.
| Auricle | |
|---|---|
 The auricula. Lateral surface. | |
| Details | |
| Artery | posterior auricular, anterior auricular |
| Nerve | Trigeminal nerve, great auricular nerve, lesser occipital nerve |
| Lymph | To pre- and post-auricular nodes, nodes of parotid and cervical chains |
| Identifiers | |
| Latin | auricula |
| MeSH | D054644 |
| TA98 | A15.3.01.002 |
| TA2 | 104, 6863 |
| FMA | 56580 |
| Anatomical terminology | |
