The physical examination of the ears of infants is important because many abnormalities can be detected, including structural problems, otitis media, and hearing loss.
The goals are to determine the position, shape, and features of the ear and to detect abnormalities. Note ear position in relation to the eyes. An imaginary line drawn across the inner and outer canthi of the eyes should cross the pinna or auricle; if the pinna is below this line the infant has low-set ears. Draw this imaginary line across the face of the baby; note that it crosses the pinna.
Otoscopic examination of the newborn's ear can detect only patency of the ear canal because accumulated vernix caseosa obscures the tympanic membrane for the first few days of life.
A small skin tab, cleft, or pit found just forward of the tragus represents a remnant of the first branchial cleft and usually has no significance. However, occasionally it may also be associated with renal disease and acquired hearing loss if there is a family history of hearing loss.
The infant's ear canal is directed downward from the outside; therefore, pull the auricle gently downward, not upward, for the best view of the eardrum. Once the tympanic membrane is visible, note that the light reflex is diffuse; it does not become cone-shaped for several months.
The acoustic blink reflex is a blinking of the infant's eyes in response to a sudden sharp sound. You can produce it by snapping your fingers or using a bell, beeper, or other noisemaking device approximately 1 foot from the infant's ear. Be sure you are not producing an airstream that may cause the infant to blink. This reflex may be difficult to elicit during the first 2 to 3 days of life. After it is elicited several times within a brief period, the reflex disappears, a phenomenon known as habituation. This crude test of hearing certainly is not diagnostic. Most newborns in the United States undergo hearing screenings, which are mandatory in the majority of states.
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