Structure
The human ear canal is divided into two parts. The fibrocartilaginous part forms the outer third of the canal, Its anterior and lower wall are cartilaginous, whereas its superior and back wall are fibrous. The cartilage is the continuation of the cartilage framework of pinna. The bony part forms the inner two thirds. The bony part is much shorter in children and is only a ring (annulus tympanicus) in the newborn.
Size and shape of the canal vary among individuals. The canal is approximately 35 mm long and 5 to 10 mm in diameter. It has a sigmoid form and runs from behind and above downward and forward. On the cross-section, it is of oval shape. These are important factors to consider when fitting earplugs.
Read more about this topic: Ear Canal
Famous quotes containing the word structure:
“There is no such thing as a language, not if a language is anything like what many philosophers and linguists have supposed. There is therefore no such thing to be learned, mastered, or born with. We must give up the idea of a clearly defined shared structure which language-users acquire and then apply to cases.”
—Donald Davidson (b. 1917)
“If rightly made, a boat would be a sort of amphibious animal, a creature of two elements, related by one half its structure to some swift and shapely fish, and by the other to some strong-winged and graceful bird.”
—Henry David Thoreau (1817–1862)
“Women over fifty already form one of the largest groups in the population structure of the western world. As long as they like themselves, they will not be an oppressed minority. In order to like themselves they must reject trivialization by others of who and what they are. A grown woman should not have to masquerade as a girl in order to remain in the land of the living.”
—Germaine Greer (b. 1939)