What Structures Make Up the Outer Ear?

Hearing is a complex process that involves picking up sounds and giving a meaning to them, says the American Speech-Language-Hearing Association. The most visible part of the human ear is the external part, called the outer ear, which is fully developed at birth. The structures that make up the outer ear are the auricle or pinna, the ear canal and the lobule.

Auricle

• According to the American Speech-Language-Hearing Association, the auricle or pinna is made of cartilage, which gives it its shape, and soft tissues such as skin, which makes it flexible. The auricle serves as a collector of sound vibrations. Its main function is to conduct such vibrations into the ear canal.

  In humans, a rudimentary auricle forms by the 60th day of embryonic life. When the fetus reaches the fourth month, the auricle has its definitive shape, according to Otolaryngology Online.

Ear Canal

• The ear canal, roughly an inch long, extends from the auricle to the eardrum or tympanic membrane. The ear canal is cartilage covered with skin. It contains glands that secrete wax, which help to prevent insects, dust and other particles from reaching the eardrum, according to the American Speech-Language-Hearing Association.

  A human fetus has ear canals by the 28th week of development, reports Otolaryngology Online.

Lobule

• The lobule is the fleshy lower part of the auricle. According to the Encyclopaedia Britannica, this is the only area of the outer ear that does not contain cartilage.

  Lobule size varies; according to a study published on Wiley Online Library, Indians have smaller ear lobules than Caucasian and Japanese populations. The study involved 260 males from the ages of 1 to 80 in the northwest region of India.