The external ear is examined by inspection and direct palpation, and the tympanic membrane is inspected with an otoscope and indirect palpation with a pneumatic otoscope. Until the advent of middle ear endoscopy, inspection of the middle ear was im-possible. Evaluation of gross auditory acuity also is included in every physical examination.
Inspection of the external ear is a simple procedure, but it is often overlooked. The auricle and surrounding tissues should be in-spected for deformities, lesions, and discharge, as well as size, symmetry, and angle of attachment to the head. Manipulation of the auricle does not normally elicit pain. If this maneuver is pain-ful, acute external otitis is suspected. Tenderness on palpation in the area of the mastoid may indicate acute mastoiditis or inflam-mation of the posterior auricular node. Occasionally, sebaceous cysts and tophi (ie, subcutaneous mineral deposits) are present on the pinna. A flaky scaliness on or behind the auricle usually indi-cates seborrheic dermatitis and can be present on the scalp and facial structures as well.
To examine the external auditory canal and tympanic membrane, the otoscope should be held in the examiner’s right hand, in a pencil-hold position, with the bottom of the scope pointing up (Fig. 59-4). This position prevents the examiner from inserting the otoscope too far into the external canal. Using the opposite hand, the auricle is grasped and gently pulled back to straighten the canal in the adult. If the canal is not straightened with this technique, the tympanic membrane is harder to visualize because of the canal obstructing the view.
The speculum is slowly inserted into the ear canal, with the examiner’s eye held close to the magnifying lens of the otoscope to visualize the canal and tympanic membrane. The largest specu-lum that the canal can accommodate (usually 5 mm in an adult) is guided gently down into the canal and slightly forward. Be-cause the distal portion of the canal is bony and covered by a sen-sitive layer of epithelium, only light pressure can be used without causing pain. The examiner looks for any discharge, inflammation, or foreign body in the external auditory canal.
The healthy tympanic membrane is pearly gray and is posi-tioned obliquely at the base of the canal. The landmarks are iden-tified, if visible (see Fig. 59-2): the pars tensa, the umbo, the manubrium of the malleus, and its short process. A slow, circular movement of the speculum allows further visualization of the malle-olar folds and periphery. The position and color of the membrane and any unusual markings or deviations from normal are docu-mented. The presence of fluid, air bubbles, blood, or masses in the middle ear also are noted.
Proper otoscopic examination of the external auditory canal and tympanic membrane requires that the canal be free of large amounts of cerumen. Cerumen is normally present in the exter-nal canal, and small amounts should not interfere with otoscopic examination. If the tympanic membrane cannot be visualized because of cerumen, the cerumen may be removed by gently irri-gating the external canal with warm water (if there are no contra-indications to this). If adherent cerumen is present, a small amount of mineral oil or over-the-counter cerumen softener may be instilled within the ear canal, and the patient is instructed to return for subsequent removal of the cerumen and inspection of the ear.
The use of instruments such as a cerumen curette for ceru-men removal is reserved for otolaryngologists and nurses with spe-cialized training because of the danger of perforating the tympanic membrane or excoriating the external auditory canal. Cerumen buildup is a common cause of hearing loss and local irritation.
A general estimation of hearing can be made by assessing the pa-tient’s ability to hear a whispered phrase or a ticking watch, test-ing one ear at a time. The Weber and Rinne tests may be used to distinguish conductive loss from sensorineural loss when hearing is impaired. These tests are part of the usual screening physical examination and are useful if a more specific assessment is needed, if hearing loss is detected, or if confirmation of audiometric results is desired.
To exclude one ear from the testing, the examiner covers the untested ear with the palm of the hand. Then the examiner whis-pers softly from a distance of 1 or 2 feet from the unoccluded ear and out of the patient’s sight. The patient with normal acuity can correctly repeat what was whispered.
The Weber test uses bone conduction to test lateralization of sound. A tuning fork (ideally, 512 Hz), set in motion by grasping it firmly by its stem and tapping it on the examiner’s knee or hand, is placed on the patient’s head or forehead (Fig. 59-5). A person with normal hearing will hear the sound equally in both ears or describe the sound as centered in the middle of the head. In cases of conductive hearing loss, such as from otosclerosis or otitis media, the sound is heard better in the affected ear.
In cases of sensorineural hearing loss, resulting from damage to the cochlear orvestibulocochlear nerve, the sound lateralizes to the better-hearing ear. The Weber test is useful for detecting unilateral hearing loss (Table 59-1).
In the Rinne test (pronounced rin-ay), the examiner shifts the stem of a vibrating tuning fork between two positions: 2 inches from the opening of the ear canal (ie, for air conduction) and against the mastoid bone (ie, for bone conduction) (Fig. 59-6). As the position changes, the patient is asked to indicate which tone is louder or when the tone is no longer audible. Normally, sound heard by air conduction is audible longer than sound heard by bone conduction. The Rinne test is useful for distinguishing between conductive and sensorineural hearing losses. With a con-ductive hearing loss, bone-conducted sound is heard as long as or longer than air-conducted sound, whereas with a sensorineural hearing loss, air-conducted sound is audible longer than bone-conducted sound. In a normal hearing ear, air-conducted sound is louder than bone-conducted sound.