In Anatomy, What Is the Auricle?
When talking about human anatomy, the auricle may refer to two distinct body parts — a part of the heart or a part of the ear. As an ear part, the auricle refers to the part of the ear that exists outside of the head. In the heart, the auricle is a part of the atrium.
In reference to the ear, the auricle is the entire external part of the ear. Most people, and especially children, think of the auricle when they refer to the "ear" as opposed to the entire ear including the middle ear and inner ear. This type of auricle is also commonly called the pinna.
The primary purpose of the auditory auricle is to collect sound. Its shape is designed to not only amplify sound, but to filter it as well. To achieve this perhaps seemingly simple task, eleven different parts of the auricle work in concert to collect and filter sound. Sounds are amplified and directed from outside of the person and into the auditory canal via the auricle.
The auricle works differently depending on the frequency of a sound. Low frequencies are directed toward the auditory canal. There is an extra phase of noise filtering for high-pitch sounds, which makes its filtering function even more valuable.
When referencing the heart, the auricle is a term used to describe one of two sections of the two atria that are part of the heart. The two different auricles are known as the right and left auricles. In older references, right and left auricles are used to describe the entire left and right atrium. More currently, the term auricle is used with more precise meaning. It refers to the small, cone-shaped, muscular pouch that projects from the atrium. Both auricles help their respective atria hold more blood. In this respect, they essentially serve as reservoirs.
The right auricle, also commonly called the right auricular appendix, is typically larger than the left auricle, also known as the left atrial appendage. Similarly, the right atrium is larger than the left atrium. This is largely because of their different functions. The right atrium accepts de-oxygenated blood that is returning to the heart from the upper body via the superior vena cava and from the lower body via the inferior vena cava. The left atrium receives oxygenated blood returning to the heart from the lungs via the pulmonary vein. The auricles are the pouches located at the receiving end of the atria.
Written by Jacob Harkins
