(accommodation or convergence). Side-to-side differences should be noted. Cranial nerves III, IV, and VI, oculomotor, trochlear, and abducens nerves: Move a pen in an H pattern 30 to 40 cm in front of the patient. Ask the patient to follow the target without moving their head. Observe the eyes for symmetry of movement, deviations, lag, or nystagmus. Face, jaw, throat, and tongue Cranial nerve V, trigeminal nerve (sensory): Using a cotton ball, stroke the client’s skin along the ophthalmic division (scalp, forehead, upper eyelid) and mandibular division (chin, jaw, lower lip). Note any side-to- side differences. Cranial nerve V, trigeminal nerve (motor): Examine the function of the temporalis, masseteric, and pterygoid muscles by palpating the masseter muscles while the patient clenches their teeth and then asking them to open their mouth against resistance. If the pterygoid is weak, the jaw deviates to the side when the mouth is opened. Cranial nerve VII, facial nerve: Ask the patient to smile, frown, raise their eyebrows, and puff out their cheeks while you check for symmetry. Cranial nerve IX, glossopharyngeal nerve: Touching a tongue depressor gently to the back of the throat on one side to test the ipsilateral gage reflex can be used to assess for unilateral lesion in the glossopharyngeal nerve. Cranial nerve X, vagus nerve: Ask the patient to open their mouth and say “aaaaahhhhhh” while you observe for symmetrical elevation of the soft palate and central ascent of the uvula. Cranial nerve XII, hypoglossal nerve: Ask the client to stick out their tongue, and move it side to side. Head, neck, and shoulder Cranial nerve XI, accessory nerve: Ask the client to resist shrugging of the shoulder. When examination reveals side-to-side differences or abnormal responses, this may be an indication to refer the patient to another healthcare provider for further examination or appropriate imaging/testing. The urgency of referral depends on the full clinical picture in terms of the client’s status and symptoms. According to Taylor et al. (2021), the diagnostic accuracy of a complete cranial nerve examination is moderate at best. However, cranial nerve dysfunction may link to a wide variety and combination of potential pathologies, and a thorough medical screening during physical therapy examination for neck pain and headaches should include this element. At present, Mourad et al. (2021) report that physical therapists only rarely or occasionally perform a cranial nerve examination, so this is an area in need of improvement. Self-Assessment Quiz Question #31 Which two cranial nerves are involved in smell and hearing? a. Vagus and hypoglossal nerves.
Self-Assessment Quiz Question #30 A common location for cervical radiculopathy is the C6–C7 level. What are the possible sensory and motor radicular symptoms related to this spinal level? a. Numbness in the shoulder area, weak shoulder abduction, and decreased triceps reflex. b. Numbness on the anterior arm and radial side of the hand, weak shoulder abduction, and decreased triceps reflex. c. Numbness on the anterior arm and radial side of the hand, weak finger abduction, and decreased biceps and brachioradialis reflexes. d. Numbness on the anterior arm and radial side of the hand, weak elbow flexion and wrist extension, and decreased biceps and brachioradialis reflexes. Cranial nerves Serious pathologies of the neck can potentially result in cranial nerve palsy, especially cranial nerves V, VI, VII, IX, I, and XII (Mourad et al., 2021). Subtle cranial nerve palsy is known to be a preischemic feature of carotid artery dissection due to the proximity of the lower cranial nerves (IX, X, XII) to the carotid sheath (Taylor et al., 2021). The lower cranial nerves should be considered in cases of both headache and neck pain. As such, a thorough physical examination should include assessment of the cranial nerves.
Evidence-based practice: A thorough evaluation of the cervical spine should include assessment of cranial nerve function. Six of the cranial nerves have been shown to be more frequently affected by serious pathologies of the neck. These include cranial nerve V (trigeminal nerve), cranial nerve VI (abducens nerve), cranial nerve VII (facial nerve), cranial nerve IX (glossopharyngeal nerve), cranial nerve I (olfactory nerve), and cranial nerve XII (hypoglossal nerve) (Mourad et al., 2021).
Cranial nerve function The cranial nerves have sensory functions, including vision, smell, hearing, taste, and facial sensations. The also contribute to eye movement; head, neck, and shoulder function; and jaw, tongue, and throat functions such as speech, swallowing, and gagging. As such, some of the cranial nerves have motor functions, some have sensory functions, and some have both (Taylor et al., 2021). Testing the cranial nerves The cranial nerves can be tested easily and quickly in the clinic as follows. Smell and hearing Cranial nerve I, olfactory nerve: Ask the patient to close their eyes and one nostril, introduce a familiar smell (a Sharpie marker works well in the clinic), and ask them to identify it. Repeat on the opposite side and note any side- to-side differences. Cranial nerve VIII, vestibulocochlear nerve: Rub your fingers near each of the patient’s ears and note any side-to-side differences. Eyes Cranial nerve II, optic nerve: Ask the patient to cover one eye. Then bring a pen or finger in from four directions diagonally toward the center of the visual field. The patient reports when the pen/finger becomes detectable and any visual field cuts are noted. Cranial nerve III, oculomotor nerve: Ask the patient to outstretch their arm and raise their index finger. Now have them move the finger toward their nose, following it with their eyes
b. Facial and glossopharyngeal nerves. c. Olfactory and vestibulocochlear nerves. d. Trigeminal and oculomotor nerves.
Self-Assessment Quiz Question #32 The cranial nerve that can be tested by resisting the client’s ability to shrug the shoulders is:
a. Cranial nerve X, the hypoglossal nerve. b. Cranial nerve XI, the accessory nerve. c. Cranial nerve V, the trigeminal nerve. d. Cranial nerve XII, the hypoglossal nerve.
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Book Code: PTNY1024
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