WEEK 1: Anatomy of the ear Flashcards
State the 3 main parts that make up the ear.
The ear can be divided into three parts: external, middle and inner.
State the parts that make up the external ear.
The external ear can be divided functionally and structurally into two parts: the auricle (or pinna), and the external acoustic meatus.
Describe and state the function of the auricle or pinna.
- It functions to capture and direct sound waves towards the external acoustic meatus.
- It is a mostly cartilaginous structure, with the lobule being the only part not supported by cartilage.
Outline and describe the different parts of the pinna.
PARTS OF THE AURICLE
* Helix: The helix is the outer rim or edge of the pinna. It forms the curved shape of the outer ear.
* Antihelix: Located inside the helix, the antihelix is a curved prominence. It helps to direct sound waves into the ear canal.
* Tragus: The tragus is a small, triangular-shaped projection located in front of the ear canal.
* Antitragus: Opposite the tragus, the antitragus is a small protrusion of cartilage.
* Concha: The concha is the concave bowl-shaped depression located between the tragus and antihelix.
* Earlobe (lobule): The earlobe is the soft, fleshy lower part of the pinna. It has no cartilage and is mainly composed of skin and fat.
Describe the External Acoustic Meatus and state its function.
The external acoustic meatus does not have a straight path, and instead travels in an S-shaped curve as follows:
*Initially it travels in a superoanterior direction.
*In then turns slightly to move superoposteriorly.
*It ends by running in an inferoanterior direction.
The walls of the external 1/3 are formed by cartilage, whereas the inner 2/3 are formed by the temporal bone.
The external acoustic meatus is a sigmoid shaped tube that extends from the deep part of the concha to the tympanic membrane.
FUNCTION
It conducts sound waves from the pinna to the tympanic membrane.
