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Clinical Anatomy 27:25–30 (2014) MEDICAL EDUCATION Cranial Nerve Assessment: A Concise Guide to Clinical Examination 1* 2 3 4,5 OMPRAKASH DAMODARAN, ELIAS RIZK, JULIAN RODRIGUEZ, AND GABRIEL LEE 1 2 Department of Neurosurgery, Liverpool Hospital, Sydney, Australia Penn State University Hershey Medical Center, Department of Neurosurgery Hershey, Pennsylvania 3Department of Clinical Neurophysiology, Fremantle Hospital, Western Australia, Perth, Australia 4Interhospital Neurosurgical Service, Sir Charles Gairdner Hospital, Perth, Australia 5 University of Western Australia, Perth, Australia Examination of the cranial nerves is an integral and important part of a complete neurological examination. Historically, these skills were crucial for diagnosing specific lesions. With the development of modern imaging modalities, the signifi- cance of clinical examination techniques has perhaps been undermined. The authors present an overview of each cranial nerve with a concise summary of examination techniques. Clin. Anat. 27:25–30, 2014. V 2013 Wiley Periodicals, Inc. Key words: cranial nerves; examination; neurological Medicine is a Science of Uncertainty and tory stria and end in the pyriform cortex (uncus, entrohinal area, and limen insulae). The medial olfac- an Art of Probability tory striae terminate in the anterior olfactory nucleus (William Osler) and in the region of the anterior perforated substance. Olfaction is the only sensation not directly connected Examination of the cranial nerves is an integral and important part of a complete neurological examination. to the thalamus. It is important to note that the true Historically, these skills were crucial for diagnosing neural networks subserving olfaction are probably specific lesions. This made diagnostic medicine an art much more complex as olfaction is closely integrated of “probability” and treatment during those early years with memory, emotions and alimentary pleasures. “a science of uncertainty.” With the development of modern imaging modalities, the significance of clinical examination techniques has perhaps been under- Examination mined. In particular, skills in neurological examination Testing of olfaction is often overlooked in clinical are often considered challenging to learn by medical examination. Anosmia can be the only localizing sign students and junior clinicians. However, a systematic of lesions in basi-frontal areas compromising the and consistent approach allows a complete and thor- olfactory pathways. It should be noted that anosmic ough examination to be performed in a timely manner. patients do not always complain about loss of smell, The authors present an overview of each cranial nerve but rather about altered taste. with a concise summary of examination techniques. The clinical examination begins with assessing the external appearance of the nose to look for any Olfactory Nerve (CN I) obvious deformity. One nostril should be occluded to Anatomy snapshot. As the name implies, the olfactory nerve serves the sense of olfaction or smell. Additional Supporting Information may be found in the online version of this article. Its fibers arise in the mucous membranes of the nose *Correspondence to: Omprakash Damodaran, Department of and pass through the cribriform plate of the ethomoid Neurosurgery, Liverpool Hospital, NSW 2170 Australia. bone to synapse in the olfactory bulb. From here, the E-mail:domprakash@hotmail.com olfactory tract follows the ventral surface of the frontal lobe and ends in the olfactory trigone. The olfactory Received 23 September 2013; Accepted 29 September 2013 tract lies in the olfactory sulcus on the orbital surfacePublished online 5 December 2013 in Wiley Online Library of the frontal lobe. Most axons follow the lateral olfac-(wileyonlinelibrary.com). DOI: 10.1002/ca.22336 V 2013 Wiley Periodicals, Inc. 0 2 5 2 1 , D 26 Damodaran et al. w l d facilitate separate testing of each side. While a range 20/20 (6/6) vision, the pinhole test can be performed d o of products can be used for testing, it is more practical using a piece of cardboard with a tiny (2 mm) perfora- m t to use commonly accessible items such as coffee, tion. Improved vision indicates refractory error. If a / orange peel, vanilla etc. Noxious stimuli are detected patient is unable to read the largest letters on the chart, n n by sensory fibers of the trigeminal nerve and pungent he or she should be asked to count fingers held up in i smells are best avoided. If anosmia is detected, an front of them. Failing this, recognition of hand move- a w examination of the nasal passages should be consid- ment is tested. In cases of severe visual impairment, l ered to rule out nasal polyps and mucosal thickening. light perception should be tested using a pen torch. . m Common causes of anosmia include respiratory tract Visual fields. Visual fields can be examined by con- d infection, increasing age, head injury, olfactory groove frontation using the examiner’s finger or colored pen, 1 . meningioma and following meningitis. but a red pen allows a more detailed assessment to 0 be made. Using a waggling finger can reduce the sen- c 2 sitivity of the test in the peripheral field and can fail 3 Optic Nerve (CN II) entirely to assess the central fields (Fig. 1). 6 y The examiner should ensure that his/her line of e Anatomy snapshot. This is a purely sensory nerve. c It is a unique fiber pathway and not a peripheral nerve sight is level with that of the patient. The patient is b instructed to look directly at the examiner’s eye while L and it connects the retina to the brain. The first order b neurons are activated by the rods and cones in the ret- the nontested eye remains covered with a piece of v cardboard (or the patient’s hand). The red pen should n ina, the true peripheral nerves in this instance. These ) bipolar cells synapse with ganglion cells, which con- be brought in from four directions diagonally towards W the center of the visual field. The patient should state e verge to the optic disc and form the optic nerve. Each O optic nerve passes through the optic canal and joins its when the colored pen becomes clearly detectable. As l this examination relies on comparative evaluation, the e counterpart to form the chiasm. The spatial orientation i examiner should ensure that the red pen is always a of fibers from different parts of the fundi is preserved equidistant from each individual. An enlarged blind y so that fibers from the lower part of the retina are n spot can also be mapped by asking about disappear- 5 found in the inferior part of the chiasm and vice versa. 3 Of note, the papillomacular bundle, which originates in ance of the pen around the center of the field of 0 vision, but this can be more challenging to test. 4 the peripheral portions of the optic nerve located S slightly inferior and lateral, becomes more centrally e e located at the level of the chiasm. Fibers from the tem- Fundoscopy T poral visual field cross over at the chiasm but fibers m Fundoscopic examination is performed using the a from the nasal fields do not. From the chiasm the optic d tract reaches three destinations: (1) the lateral genicu- ophthalmoscope to assess the optic disc and retina o while the patient is looking into the distance. Regular d late body for relay to the visual cortex in the occipital o practice is required to achieve competence, particu- s cortex; (2) pretectal nuclei for papillary reflexes to light; t and (3) the superior colliculi for body reflexes to light. larly when examining patients with undilated pupils. s o The optic radiation from the lateral geniculate body n divides before reaching the visual cortex. The fiber l Oculomotor, Trochlear, and Abducens a tracts that originate from the upper retinal quadrants . pass through the internal capsule and course within Nerves (CN III, IV, and VI) i y the parietal and occipital lobes to terminate on the o cuneus. The lower retinal fibers pass through the Anatomy snapshot. Cranial nerves III, IV, and VI t provide motor innervations to extra-ocular muscles. m internal capsule and sweep around the temporal horn - of the lateral ventricle forming Meyer’s loop, eventu- The oculomotor nucleus is situated in the periaqueduc- d tal gray at the level of the superior colliculus. The oculo- o ally terminating in the lingual gyrus. d motor nerve provides somatic motor inputs to all the o extra-ocular muscles except the lateral rectus (abdu- ) n Examination cens nerve) and superior oblique (trochlear nerve). W e Pupil size depends on a balance between sympathetic O Each eye should be tested separately in assess- (midriasis) and parasympathethic (miosis) tone. The l ments of visual acuity, visual fields, and fundoscopy. e parasympathetic innervation is through the Edinger b Visual acuity. As refractory errors are not part of cra- Westphal nucleus located dorsal to CN III. Preganglionic a f nial nerve examination, the patient should use any opti- parasympathetic fibers travel to the ciliary ganglion r cal aids to which they are accustomed. A hand-held eye where postganglionic fibers relay to the pupil and ciliary l o chart or a Snellen chart can be used. During the exami- muscle. Sympathetic innervation to the eyes travels u nation, one eye should be completely covered with a from the hypothalamus via the ciliospinal center in the ; A small card. The examiner should be mindful that spinal cord at C8, T1, and T2 to the superior cervical a patients with impaired vision may tend to turn their ganglion in the neck. From here the sympathetic fibers c s head, thus inadvertently looking with the covered eye. travel with the internal carotid artery into the cavernous r Depending on the Snellen chart used, the patient should sympathetic plexus. This in turn travels within the oph- g e be tested at a distance of 20 feet (6 m) or 10 feet (3 m). thalmic division of the trigeminal nerve to innervate the e b The patient is asked to read progressively smaller letters eye through the long and short ciliary nerves. Of note, t until consistent perception is no longer possible. In a the sympathetic plexus also innervates the tarsal e p patient who has uncorrected visual acuity of less than muscles and the orbital muscle of Muller. € c b C e v C m m s i n e 0 8 5 , 0 4 , Cranial Nerve Assessment 27 D w o d d o m p / n n i a y i y o / o 0 1 2 c 2 3 6 y e c b ( a v a c , i y O i e Fig. 1. CN II lesions and associated visual field deficits. b r o n 5 The trochlear nerve (CN IV) is located immediately look into the far distance and then asked to focus on 3 0 beneath and lateral to the occulomotor nerve in the the tip of his or her nose. Causes of an absent light 4 mesencephalon. The fibers decussate in the anterior reflex with an intact accommodation reflex include a . e medullary velum of the aqueduct of Sylvius. They midbrain lesion or a ciliary ganglion lesion. In very h then travel forward to pierce the dura, which forms rare cases, failure of accommodation only can occur T r the lateral wall of the cavernous sinus, below the ocu- after a midbrain lesion or cortical blindness. s n lomotor nerve. C The abducens nerve (CN VI) arises from the pons n Eye Movements t ventral to the fourth ventricle. Its fibers emerge ven- n ( trally between the pons and medulla, and then ascend Failure of movement, diplopia and nystagmus are t between the pons and the clivus. Dorello’s canal chan- assessed in this examination. The examiner should be : o nels the nerve towards the cavernous sinus where the 30–40 cm in front of the patient and a hat pin should n nerve courses in close proximity to the carotid artery. l be moved in an “H” pattern. Patients should be asked a to follow the target with their eyes without moving y i their heads. Look for failure of movement and ask y Examination o about diplopia. If any abnormity is detected, each eye m should be tested individually. r Pupils. The size, shape, and symmetry of pupils s should be noted on inspection. An irregular pupil can Diplopia is an early sign of extraocular muscle n - suggest previous surgery or traumatic injury. Direct weakness. The false image is usually paler, less dis- n tinct and more peripheral. The patient should be i and indirect pupillary responses to light should be eli- n cited. The direct response is the constriction that asked if the images are side by side or one above the ) other. A side by side position indicates only the lateral n occurs when the pupil is exposed to light. The consen- W sual or indirect response refers to the simultaneous and medial recti are involved. To assess the muscles e O constriction of the opposite pupil. The torch should be involved, the direction in which image separation is l maximal should be established. Image separation is e moved in an arc from pupil to pupil to assess for an i afferent pupillary defect. This is also known as the greatest in the direction of the purest muscle action of a y Marcus Gunn sign, where the affected pupil dilates the weak muscle. At the point of maximal image sep- r aration, cover one eye. Disappearance of the false u paradoxically after a short time when the light source s is moved from a normal to an abnormal eye. image indicates that the covered eye is responsible. f s The light reflex and resting pupil size are dependent O on light perception by at least one eye. If both eyes A Trigeminal Nerve (CN V) r are blind owing to a lesion anterior to the lateral genic- l s ulate bodies, both pupils will be fixed and nonreactive Anatomy snapshot. The trigeminal nerve is the e to light. If blindness is secondary to destruction of the largest cranial nerve and has both sensory and motor o e visual cortex the light reflex will be preserved. fibers. It emerges from the pons and runs within the e b Accommodation refers to the pupillary constriction cerebellopontine angle. At the petrous temporal bone, y that occurs as the patient attempts to converge his or it forms the trigeminal ganglion housed within Meck- e p her eyes. To test this, the patient is initially asked to el’s cave. The trigeminal ganglion gives rise to three i b e r t e o m o s c n e 0 2 5 2 1 , D 28 Damodaran et al. w l d TABLE 1. Common Mistakes in Cranial Nerve muscles are palpated to assess for tone and muscle d o Examination bulk. The strength of these muscles can be tested by m t Cranial asking the patient to bite on a wooden tongue depres- / sor. The depth of the bite marks can be used to assess n Nerve Common Mistakes in Examination n muscle strength. The patient can also be asked to i I Only use easily recognizable agents like hold the mouth open while the examiner attempts to a coffee, rosewater w force it shut. This test assesses the strength of the l II Do not forget to inquire about eye glasses pterygoid muscles. . and use them m III, IV, VI Examination is performed too close to the An exaggerated jaw reflex can be a valuable sign d indicating an upper motor neuron lesion. After an 1 patient; Target moves too fast during . examination; Patient is allowed to move index finger is placed on the chin and a tap with the 0 tendon hammer elicits any reflex. Normally there is c head 2 V Conjunctiva is touched instead of cornea; slight closure of the mouth or no reflex at all. 3 Corneal reflex can be mildly inhibited in 6 y contact lens wearers; Movement of the e examiner triggers reflex blinking Facial Nerve (CN VII) c b VII Ptosis is not due to weakness of facial L paresis Anatomy snapshot. The facial nerve is predomi- b VIII Always inspect the ear for hearing aids, v nantly a motor nerve with parasympathetic and sen- n scars etc sory components. The sensory division is separate ) IX,X- Be mindful of aspiration risks when testing W swallowing from the motor division and is sometimes referred to e as the “nervus intermedius.” The motor nucleus is O XII- Facial paresis or asymmetry may give the l misleading impression of an asymmetrical located ventral and medial to the abducens nucleus in e the pons. The fibers then loop around the abducens i tongue during protrusion a nucleus before exiting the ponto-medullary junction y with the eighth cranial nerve to enter the internal n 5 divisions. The ophthalmic division (V1) runs within the acoustic meatus above the eighth nerve. After enter- 3 ing the facial canal the nerve enlarges to become the 0 lateral wall of the cavernous sinus to enter the orbital 4 fissure superior to supply the skin of the forehead and geniculate ganglion. The corda tympani, which contain S the taste fibers from the anterior two thirds of the e the cornea and conjunctiva. The maxillary division e (V2) supplies the skin in the middle of the face, tongue, join the nerve in the facial canal. The facial T m mucous membranes in the upper part of the mouth nerve exits the skull at the stylomastoid foramen and a palate and the nasopharynx. The mandibular division divides into its terminal branches within the parotid d o (V3) runs with the motor part of the nerve and leaves gland to supply the muscles of facial expression. The d the skull through the foramen ovale to supply the skin efferent parasympathetic fibers initiate salivation, lac- o s of the lower jaw and muscles of mastication (tempo- rimation and mucous membrane secretion. These t fibers travel in the corda tympani nerve to supply the s ralis, masseter, pterygoids). o submandibular, submaxillary, and lacrimal glands. n l a Examination . Examination i The three trigeminal divisions are tested using a y o cotton wool ball and blunt tip needle sequentially on The facial nerve provides innervation for the t the forehead, malar eminence and lower face over the muscles of facial expression. Close observation of a m - mandible, while comparing sides. Loss of pain sensa- patient’s face can yield the initial clues of asymmetri- d tion will result in the pin prick feeling dull. The area of cal expression (e.g., flattening of the nasolabial o d dullness should be mapped. Light touch can be tested groove) in a patient with facial nerve palsy. The upper o with cotton wool, but temperature is rarely tested part of the face is relatively spared in facial paresis of ) n except in syringobulbia. an upper motor neuron pattern owing to bilateral cort- W e Corneal reflex testing is simple to perform but ical representation. This can be tested by instructing O potential problems must be recognized. The assessor the patient to look upwards, which can exaggerate the l e should ideally be positioned to the side or behind the wrinkling the forehead. Next, the patient should be b patient to avoid a blink reflex, which can be triggered asked to close both eyes tightly while the examiner a f by sudden movements in the patient’s visual field. A attempts to force open each eye to test strength. To r wisp of cotton is used to touch the cornea gently while assess the muscles of expression in the lower face, l o the patient is gazing towards the distance. The exam- the patient is asked to show his/her teeth and to “puff u iner should ask if the patient felt the corneal contact out” the cheeks, and then the cheeks are palpated to ; A and look for blinking in both eyes. Reflex blinking of determine any difference in tone. A lower motor neu- a both eyes is a normal response. If blinking occurs ron lesion results in paresis/paralysis of all the ipsilat- c s only in the contralateral eye, this can indicate ipsilat- eral facial muscles. r eral seventh nerve palsy. Unilateral upper motor neuron facial nerve paresis g e The motor component of the trigeminal nerve can can commonly result from vascular lesions or tumors. e b be assessed by examining the function of the tempo- A lower motor neuron pattern of facial paresis is seen t ralis, masseteric and pterygoid muscles. With the in Bell’s palsy, multiple sclerosis and tumors (e.g., e p patient clenching, the temporalis and masseteric meningiomas and vestibular schwannomas) that c b C e v C m m s i n e 0 2 5 2 1 , D Cranial Nerve Assessment 29 w l d compress the facial nerve. Bilateral facial nerve weak- marily the muscles of the tongue and pharynx. The d o ness is uncommon. Causes include Guillain–Barre nerve emerges from the medulla as three to six root- m t syndrome, sarcoidosis and bilateral parotid disease. lets between the inferior olive and the inferior cerebel- / lar peduncle. It exits through the jugular foramen n n Vestibulocochlear Nerve (CN VIII) within a separate dural sheath (lateral and anterior to i CNs X and XI). The glossopharyngeal nerve then trav- a w Anatomy snapshot. This nerve is sensory, special- els within the carotid sheath and ultimately terminates l in the lateral pharyngeal wall. The nerve provides . ized for sound reception and balance. Fibers for hearing m originate in the hair cells of the organ of Corti. They both sensory and motor innervations to structures in d the glossopharynx. Efferent nerves innervate the sty- 1 travel towards the bipolar cells of the spiral ganglion . within the cochlea. The nerve emerges from the coch- lopharyngeus muscle. Autonomic fibers supply the 0 parotid gland and mucous membranes of the posterior c lea and passes through the internal acoustic meatus to 2 enter the upper medulla at its junction with the pons. inferior mouth and membranes through the tympanic 3 nerve (Jacobson’s nerve). 6 The fibers terminate in the cochlear nuclei located in y the pons. Fibers for balance originate in the maculae of Afferent fibers arise from the retroauricular region e c the utricle and saccule and the cristae of the ampullae with tactile, thermal and noxious stimuli from the b mucous membranes of the posterior third of the L of the semicircular canals. Impulses travel to the bipo- b lar cells of Scarpa’s ganglion. The vesibular nerve tongue, the tonsils, and the Eustachian tube. Taste v sensation is carried from the posterior tongue region. n emerges through the internal auditory meatus to join ) the auditory fibers in the facial canal. The nerve even- Hering’s nerve, a special visceral afferent nerve, arises W just below the jugular foramen. It innervates the e tually enters the brainstem at the ponto-medullary O junction and relays in the vestibular nuclei. carotid sinus and body and brings chemo- and l baro-receptor inputs to the medulla. Together e i with collateral inputs via the vagal nerve, the a Examination glossopharyngeal-vagal reflex slows the heart rate or y n lowers blood pressure. 5 Auditory. Hearing. Test one ear at a time. A sim- 3 ple test would involve blocking the contralateral ear 0 4 with a finger and whispering numbers in the ipsilateral Examination S e ear. Numbers such as 68 can be used to test for high Clinical examination of the glossopharyngeal nerve e tone and 100 for low tone. Whispering should be per- T is typically performed in conjunction with the vagus m formed at the end of respiration at distance of 60 cm nerve, as separate testing is challenging. A unilateral a to standardize the examination. If any deficits are d lesion in the glossopharyngeal nerve can manifest as o noted, Rinne’s and Weber’s tests are performed. loss of the ipsilateral gag reflex, carotid body and d Rinne’s test. A 256 Hz tuning fork is struck and o sinus reflex and taste in the posterior region of the s placed on the mastoid process. The patient is t requested to indicate when the sound is no longer tongue. In practice, only the gag reflex is assessed. s The examiner should explain the procedure thor- o audible. As soon as the sound is extinguished, the n tuning fork is placed next to the external auditory oughly and state that it may be uncomfortable, so l that the patient knows what is to be expected prior to a meatus to assess whether it can be heard. In a . testing. With a tongue depressor, the back of the i patient with normal hearing, air conduction should be throat is touched gently on one side. This normally y greater than bone conduction, so the patient should o triggers the gag reflex. If this is weakened or absent, t be able to hear the tuning fork next to the ear after it the patient should be asked if the sensation was felt m is no longer audible against the mastoid. With conduc- - equally on both sides. d tive deafness, the patient will not be able to hear the o tuning fork when it is moved next to the external d o auditory meatus. In sensorineural deafness, the mas- ) toid and external auditory meatus components are Vagus Nerve (CN X) n W equally reduced. e Weber’s test. A 256-Hz tuning fork is placed in the Anatomy snapshot. The vagus nerve also origi- O nates in the medulla and innervates multiple struc- l middle of the forehead and the sound is heard from e there. In sensorineural deafness the sound is heard tures. The Latin root of its name translates as b “wandering,” reflecting its long and wide distribution. a better in the normal ear. A patient with conduction f The nerve exits just below the glossopharyngeal nerve r deafness finds the sound louder in the abnormal ear. in the medulla. It courses towards the jugular fora- l Vestibular system. A bedside examination of the o men, posterior and medial to CN IX, then travels u vestibular system is difficult to perform. This system down in the carotid sheath. Like the glossopharyngeal ; can be assessed indirectly, without performing speci- A nerve, this nerve contains both afferent and efferent a alized tests such as Hallpike’s maneuver, by assessing projections. The efferent innervations convey general c s the patient’s gait and looking for nystagmus. visceral efferents to the thorax, abdominal viscera, r and muscles of the pharynx and larynx. Afferents g e Glossopharyngeal Nerve (CN IX) arise from the external ear, external auditory canal, e b surface of the tympanic membrane, pharynx, larynx, t Anatomy snapshot. As the name implies, this trachea, esophagus and viscera of the thorax and e p nerve originates from the medulla and innervates pri- abdomen. c b C e v C m m s i n e 0 8 5 , 0 4 , 30 Damodaran et al. o w o e Examination examination focuses on the bulky muscles innervated f o by the spinal portion of the nerve. The tone and bulk h The vagus nerve is typically evaluated in conjunc- of the sternocleidomastoid and trapezius muscles are p tion with the glossopharyngeal nerve. The examiner / initially examined by close observation and palpation. n should take note of the patient’s voice during conver- n The trapezius is tested by asking the patient to shrug b sation. An isolated recurrent laryngeal nerve (branch their shoulders while applying resistance. In severe a of the vagus nerve) palsy results in a hoarse voice. . cases of ipsilateral trapezius muscle atrophy, shoulder l When the patient is asked to cough, the failure of sag with downward and outward rotation of the scap- . vocal cord closure produces a hollow “bovine” sound. o ula can be observed. The sternocleidomastoid is d Unilateral vagus nerve lesions result in hoarseness, i assessed by asking the patient to turn his/her head 0 dysphagia and dyspnea secondary to loss of branchio- against resistance applied to the side of the face. In 0 meric muscle innervations. While testing the gag 2 cases of unilateral palsy, the patient is unable to turn a reflex, the examiner should note the position of the the head to the side opposite the lesion as the sterno- 2 3 uvula and look for symmetrical elevation of the soft cleidomastoid muscle is weak. b palate to exclude uvular deviation away from the side R a of the vagus nerve lesion. A simple bedside swallow- c ing assessment can also be performed by asking the Hypoglossal Nerve (CN XII) e L patient to drink small sips of water. Patients with bul- Anatomy snapshot. The hypoglossal nerve pro- b v bar palsy can be at risk of aspiration. Bilateral vagal vides motor innervation to the tongue musculature. n nerve injuries are usually fatal owing to laryngeal . The hypoglossal nucleus resides primarily in the W paralysis, which results in airway obstruction and medulla oblongata. The exiting fibers emerge from a l asphyxia. y sulcus between the pyramid and inferior olive. The n n nerve then enters the hypoglossal canal and exits L Spinal Accessory Nerve (CN XI) towards the angle of the mandible. It subsequently r y courses anteriorly to supply both the intrinsic and n Anatomy snapshot. The spinal accessory nerve is extrinsic tongue muscles. 1 / formed from cranial and spinal contributions. The spi- / nal roots arise from the ventral horn cells in the cord 2 Examination ] from C1-C5 and travel cranially through the foramen S e magnum. These fibers travel in turn to the clivus, The tongue is carefully inspected for signs of atro- e turning laterally towards and then exiting through the phy and asymmetry. With atrophy the tongue starts e m jugular foramen after joining the cranial portion dis- to lose its bulk at the tip and the border area. This a d cussed above. progresses until it appears wrinkled. The patient is o The spinal portion of the nerve innervates the ster- then asked to protrude the tongue; there is tongue d o nocleidomastoid and upper part of the trapezius deviation towards the side of the lesion in pathological s through somato-motor fibers. The cranial portion com- conditions. Fasciculations may be seen in patients h s municates with the jugular ganglion of the vagus with motor neuron disease (amyotrophic lateral scle- / l nerve, and innervates the intrinsic muscles of the rosis). While the tongue is at rest, fasciculations usu- e pharynx through the recurrent laryngeal nerve branch. ally persist while resting tremors abate. Power is b r examined by having the patient press the tip of the w e Examination tongue against each cheek while the examiner tries to c dislodge it. With facial weakness, tongue deviation m e A lesion or injury to the cranial portion of the spinal can appear to be produced when none is present. m accessory nerve is difficult to distinguish from one of Hence, manual elevation of the weak side of the face a d the vagal nerve, as described above. Hence, clinical can be helpful in eliminating this finding. o d o s n W e O n e L r y o u e o s ; A r c s r g e n d y e p i b e r t e C m o s i n e