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:
“The verbal poetical texture of Shakespeare is the greatest the world has known, and is immensely superior to the structure of his plays as plays. With Shakespeare it is the metaphor that is the thing, not the play.”
—Vladimir Nabokov (1899–1977)
“The question is still asked of women: “How do you propose to answer the need for child care?” That is an obvious attempt to structure conflict in the old terms. The questions are rather: “If we as a human community want children, how does the total society propose to provide for them?””
—Jean Baker Miller (20th century)
“Why does philosophy use concepts and why does faith use symbols if both try to express the same ultimate? The answer, of course, is that the relation to the ultimate is not the same in each case. The philosophical relation is in principle a detached description of the basic structure in which the ultimate manifests itself. The relation of faith is in principle an involved expression of concern about the meaning of the ultimate for the faithful.”
—Paul Tillich (1886–1965)