Palpating Masseter Muscles

Sensory. After explaining what you plan to do, test the forehead, cheeks, and jaw on each side for pain sensation. Suggested areas are indicated by the circles. The patient's eyes should be closed. Use a safety pin or other suitable sharp object,* occasionally substituting the blunt end for the point as a stimulus. Ask the patient to report whether it is "sharp" or "dull" and to compare sides.

Unilateral decrease in or loss of facial sensation suggests a lesion of CN V or of interconnecting higher sensory pathways. Such a sensory loss may also be associated with a conversion reaction.

*To avoid transmitting infection, use a new object with each patient. You can create a sharp wood splinter by breaking or twisting a cotton swab. The cotton end of the swab can also be used as a dull stimulus.

If you find an abnormality, confirm it by testing temperature sensation. Two test tubes, filled with hot and ice-cold water, are the traditional stimuli. A tuning fork may also be used. It usually feels cool. If you are near running water, the fork is easily made colder or warm. Dry it before use. Touch the skin and ask the patient to identify "hot" or "cold."

Then test for light touch, using a fine wisp of cotton. Ask the patient to respond whenever you touch the skin.

Test the corneal reflex. Ask the patient to look up and away from you. Approaching from the other side, out of the patient's line of vision, and avoiding the eyelashes, touch the cornea (not just the conjunctiva) lightly with a fine wisp of cotton. If the patient is apprehensive, however, first touching the conjunctiva may allay fear.

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Look for blinking of the eyes, the normal reaction to this stimulus. (The sensory limb of this reflex is carried in CN V, the motor response in CN VII.) Use of contact lenses frequently diminishes or abolishes this reflex.

Cranial Nerve VII—Facial. Inspect the face, both at rest and during conversation with the patient. Note any asymmetry (e.g., of the nasolabial folds), and observe any tics or other abnormal movements.

Ask the patient to:

1. Raise both eyebrows.

Absence of blinking suggests a lesion of CN V. A lesion of CN VII (the nerve to the muscles that close the eyes) may also impair this reflex.

Flattening of the nasolabial fold and drooping of the lower eyelid suggest facial weakness.

A peripheral injury to CN VII, as in Bell's palsy, affects both the upper and the lower face; a central lesion affects mainly the lower face. See Table 16-10, Types of Facial Paralysis (pp. 612-613).

3. Close both eyes tightly so that you cannot open them. Test muscular strength by trying to open them, as illustrated.

4. Show both upper and lower teeth.

6. Puff out both cheeks.

Note any weakness or asymmetry.

Cranial Nerve VIII—Acoustic. Assess hearing. If hearing loss is present, (1) test for lateralization, and (2) compare air and bone conduction (see pp. 156-158).

Specific tests of vestibular function are seldom included in the usual neurologic examination. Consult textbooks of neurology or otolaryngology as the need arises.

Cranial Nerves IX and X—Glossopharyngeal and Vagus. Listen to the patient's voice. Is it hoarse or does it have a nasal quality?

Is there difficulty in swallowing?

Ask the patient to say "ah" or to yawn as you watch the movements of the soft palate and the pharynx. The soft palate normally rises symmetrically, the uvula remains in the midline, and each side of the posterior pharynx moves medially, like a curtain. The slightly curved uvula seen occasionally in a normal person should not be mistaken for a uvula deviated by a 10th nerve lesion.

Warn the patient that you are going to test the gag reflex. Stimulate the back of the throat lightly on each side in turn and note the gag reflex. It may be symmetrically diminished or absent in some normal people.

Cranial Nerve XI—Spinal Accessory. From behind, look for atrophy or fasciculations in the trapezius muscles, and compare one side with the

In unilateral facial paralysis, the mouth droops on the paralyzed side when the patient smiles or grimaces.

See Table 5-19, Patterns of Hearing Loss (pp. 196-197).

Nystagmus may indicate vestibular dysfunction. See Table 16-9, Nystagmus (pp. 610-611).

Hoarseness in vocal cord paralysis; a nasal voice in paralysis of the palate

Pharyngeal or palatal weakness

The palate fails to rise with a bilateral lesion of the vagus nerve. In unilateral paralysis, one side of the palate fails to rise and, together with the uvula, is pulled toward the normal side (see p. 162).

Unilateral absence of this reflex suggests a lesion of CN IX, perhaps CN X.

Weakness with atrophy and fasciculations indicates a peripheral nerve disorder. When the trapezius is paralyzed, the shoulder droops and the scapula is displaced downward and laterally.

other. Ask the patient to shrug both shoulders upward against your hands. Note the strength and contraction of the trapezii.

Ask the patient to turn his or her head to each side against your hand. Observe the contraction of the opposite sternomastoid and note the force of the movement against your hand.

Cranial Nerve XII—Hypoglossal. Listen to the articulation of the patient's words. This depends on Cranial Nerves V, VII, and X as well as XII. Inspect the patient's tongue as it lies on the floor of the mouth. Look for any atrophy or fasciculations (fine, flickering, irregular movements in small groups of muscle fibers). Some coarser restless movements are often seen in a normal tongue. Then, with the patient's tongue protruded, look for asymmetry, atrophy, or deviation from the midline. Ask the patient to move the tongue from side to side, and note the symmetry of the movement. In ambiguous cases, ask the patient to push the tongue against the inside of each cheek in turn as you palpate externally for strength.

A supine patient with bilateral weakness of the sternomastoids has difficulty raising the head off the pillow.

For poor articulation, or dysarthria, see Table 16-2, Disorders of Speech (p. 600). Atrophy and fas-ciculations in amyotrophic lateral sclerosis, polio

In a unilateral cortical lesion, the protruded tongue deviates transiently in a direction away from the side of the cortical lesion.

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