Ears

Ear disorders are disruptive to language, speech, and social development. Early screening and detection can assist in minimizing or eliminating hearing deficiencies and their effects. Temporary and correctable conditions such as otitis media are common in young children but might go undetected. Abnormalities of the external ear can be important in alerting health professionals to the presence of syndromes and should be reported. Assessment of the ear is performed in conjunction with the eye examination, because eye problems are nearly twice as common in children with hearing deficiencies.

The ear consists of the external ear, middle ear, and inner ear. The outer ear consists of the auricle, cartilaginous shell, and external ear canal. In children younger than 3 years the canal points upward; in older children it is directed downward and forward. The lining of the external ear canal secretes cerumen, which protects the ear.

The middle ear consists of the tympanum (eardrum) and three bones (ossicles) that touch the tympanum on one side and the membrane covering the opening to the inner ear on the other side. Vibrations of the tympanum are transmitted through the ossicles to the inner ear. The middle ear also contains an opening to the eustachian tube. The eustachian tube allows secretions to pass from the middle ear to the nasopharynx and enables air to enter the middle ear from the throat. Equalization of air pressure between the external ear canal and middle ear is essential for proper functioning of the tympanic membrane. The shorter and less angled eustachian tube in infants and young children permits secretions from the nose and throat to readily enter the middle ear, predisposing this age group to more frequent ear infections.

The inner ear contains auditory nerve endings, which pick up sound waves from the middle ear and transmit them along the eighth cranial nerve, or auditory nerve, to the brain. Sound waves that contact the skull directly can also be picked up by the inner ear. The inner ear contains the structures for balance and hearing.

The three divisions of the ear develop in the embryo at the same time as other vital organs are developing, which is why deformities of the ears can provide clues to developmental aberrations elsewhere in the body. External ear development begins at about the fifth week of gestation, and middle ear development begins at around the sixth week. The ears are particularly vulnerable to developmental aberration in the ninth week of gestation.

Neonates are capable of sound discrimination at birth and respond more readily to high-pitched voices. The presence of mucus in the eustachian tube can limit hearing when the neonate is first born but clears shortly after birth. Vernix caseosa in the external ear canal can make visualization of the tympanic membrane difficult.

The young infant responds to loud noises with the startle reflex, blinking, or cessation of movement. Infants 6 months of age or older attempt to locate the source of the sound.

Ask about family history of hearing problems, prenatal influences (infection, alcohol use), postnatal factors (mechanical ventilation, neonatal jaundice, asphyxia at birth), childhood infections (mumps, measles, ear and respiratory tract infections), surgery to the ear, use of ototoxic drugs, head trauma, and exposure to loud noises (e.g., music).

If an otoscopic examination is to be performed in a young child or infant, it is safer to restrain the child. Explain and demonstrate to the parent how to hold the child. The child can be placed on the side or abdomen, with the hands at the side and the head turned so that the ear to be examined points toward the ceiling. The parent can assist by placing one hand on the child’s head above the ear and the other on the child’s trunk. Alternatively, the child can sit on the parent’s lap with one arm tucked behind the parent’s back. The parent holds the child’s head against his or her shoulder and the child’s other, free arm (Figure 12-1).

Assessment	Findings
Examine the ear for placement and position.	The top of the ear should cross an imaginary line from the inner eye to the occiput. The pinna should deviate no more than 10 degrees from a line perpendicular to the horizontal line. (Use of a pen or tongue blade can provide more concrete estimations of where the ear is positioned in relation to a vertical line.) Figure 12-2 illustrates normal placement and position of the ear.