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Cranial nerve assessment..Simple and Easy to perform for medics and Physiotherapist


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Cranial Nerve Assessment is a crucial step in neurological assessment. By following the simple theoretical aspects it can be made on your is an try to make the stuff easier for …

Cranial Nerve Assessment is a crucial step in neurological assessment. By following the simple theoretical aspects it can be made on your is an try to make the stuff easier for you....

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  • 2. IV Trochlear III Oculomotor VII Facial VI Abducens V Trigeminal CEREBRAL HEMISPHERE MIDBRAIN PONS MEDULLA CRANIAL NERVES II Optic I Olfactory VIII Vestibulo- cochlear XII Hypoglossal XI Accessory X Vagus IX Glossopharyngeal CRANIAL NERVES 2
  • 3. CRANIAL NERVES  The 12 pairs of cranial nerves are part of the peripheral nervous system.  The Roman numeral is based on descending order of the cranial nerve's attachment to the CNS.  As a rule, cranial nerves do not cross in the brain.  Cranial nerves may be sensory, motor both somatic or parasympathetic, or have mixed function. General Characteristics: CRANIAL NERVES 3
  • 5. CN I - OLFACTORY • ORIGIN: Cerebral hemisphere • INNERVATION: Nasal mucous membranes. • FUNCTION: Sense of smell • DYSFUNCTION: Anosmia CLINICAL EVALUATION • Use non-noxious aromatic substances, i.e. coffee, lemon, garlic, etc. • Test each nostril separately. • Mark if any abnormality noted CRANIAL NERVES 5
  • 6. CN II – OPTIC NERVE • VISUAL ACUITY: Snellen chart for distant vision, Jaegers chart, newspaper or fingers for near vision. • VISUAL FIELDS: Confrontation. • FUNDI AND OPTIC DISCS: Visualization of the termination of the optic nerve by looking through pupil with ophthalmoscope. CRANIAL NERVES 6
  • 7. CN II – OPTIC NERVE(cont..)  Tested by- 1. Visual acuity 2. Color vision 3. Visual field CRANIAL NERVES 7 Near field Far field Color matching Confrontation test
  • 8. CN II – OPTIC NERVE(cont..)  Visual acuity-  Snellen chart(Far vision) ◦ Chart is placed at 20 feet or 6 meter and patient is asked to read it ◦ The formula is d/D  Where d is 6 meter and D is the distance from which he can read it clearly  Normal is 6/6 or 20/20  Jaegers chart(Near vision) ◦ Paragraphs are printed in successive coarser type with 0 is finest and 7 is biggest ◦ Patient is asked to read through the hole CRANIAL NERVES 8
  • 9. CN II – OPTIC NERVE(cont..)  Color vision- ◦ Checked by asking to match different colors • Day or night blindness can be assessed • Visual field-  Confrontation test  Peripheral visual fields-  Goldmann Perimeter CRANIAL NERVES 9
  • 10. SPECIFIC DYSFUNCTIONS • Blurred vision or complete blindness. • Ipsilateral vision loss - Optic atrophy, retinal/optic nerve lesions, trauma. • Visual loss (one or both eyes) - Optic chiasm or occipital lobe lesions. • Hemianopia - (loss of half of visual field in one or both eyes) - Lesions of optic chiasm, tracts, or radiations. • Cortical blindness - Lesion of occipital cortex bilaterally, pupil reflexes intact. • Papilledema - Optic nerve tumor, venous obstruction, chronic increased ICP. • Optic atrophy - MS, optic neuritis, increased ICP. • Scotomas- (Abnormal blind spots on visual fields) - optic neuritis or atrophy. CRANIAL NERVES 10
  • 11. CN III – OCULOMOTOR NERVE  ORIGIN: Midbrain  INNERVATION: EOM's; eyelid; ciliary; and sphincter of iris.  FUNCTION: Eye movement inward (medially), upward, downward, and outward; pupil Constriction, shape and equality; elevates upper eyelid; accommodation reflex.  DYSFUNCTION: Unable to look up, down, or medial (dysconjugate gaze); ptosis, pupil dilatation - bilateral or ipsilateral, and loss of accommodation reflex. CRANIAL NERVES 11
  • 12. CN III – OCULOMOTOR NERVE(cont..) • Observe for eye opening and symmetry. • Direct light response - brisk, sluggish, or non-reactive. • Consensual response - present or absent. • Pupil size and shape. • Accommodation. • Extra ocular movement (EOM's) (Abducens). CRANIAL NERVES 12
  • 13. CRANIAL NERVE FUNCTION & MUSCLE INNERVATION RELATIVE TO EYE MOVEMENT Superior rectus CN III Inferior oblique CN III Lateral rectus CN VI Medial rectus CN III Superior oblique CN IV Inferior rectus CN III
  • 14. CN IV – TROCHLEAR NERVE  ORIGIN: Midbrain  INNERVATION: Superior oblique muscle.  FUNCTION: Down and inward movement of the eye.  DYSFUNCTION: Loss of downward, inner movement of eye, dysconjugate gaze. CRANIAL NERVES 14 SUPERIOR OBLIQUE MUSCLE
  • 15. CN VI – ABDUCENS NERVE  ORIGIN: Pons  INNERVATION: Lateral rectus muscle.  FUNCTION: Outward, lateral movement of eye.  DYSFUNCTION: Loss of lateral eye movement, dysconjugate gaze. CRANIAL NERVES 15 Clinical evaluation of CN III, IV, VI •Extraocular movements (EOM's) •CN IV (Trochlear) and CN VI tested with CN III (Oculomotor) LATERAL RECTUS MUSCLE
  • 16. CN V – TRIGEMINAL NERVE  ORIGIN: Pons. The sensory nucleus extends from the pons to the midbrain, and also to the medulla and spinal cord.  INNERVATION: Three branches of CN V: Ophthalmic, maxillary, & mandibular.  Motor innervation to masseter & temporal muscles.  Sensory innervation to skin & mucous membranes in head; teeth, tongue, external auditory canal, and cornea. CRANIAL NERVES 16
  • 17. CN V – TRIGEMINAL NERVE(cont..)  FUNCTION: Sensation of pain, touch, hot, & cold; motor movement of masseter & temporal muscles.  DYSFUNCTION: Loss of sensation - if affecting all three branches, indicative of peripheral injury.  Brainstem or upper cervical cord injury may result in loss of sensation to one or more branches of the trigeminal nerve.  Loss of corneal reflex. CRANIAL NERVES 17
  • 18. CN V – TRIGEMINAL NERVE(cont..)  Paresthesia and/or severe pain indicative of nerve compression or irritation (Trigeminal neuralgia)  Deviation of jaw towards the same side, loss of sensation.  Inability to bite down and chew, inability to close jaw.  Chewing, speaking, washing face, cold water, may precipitate the attack…TRIGGER POINT CRANIAL NERVES 18
  • 19. CN V – TRIGEMINAL NERVE(cont..)  Tic douloureux or trigeminal neuralgia  Paroxysmal attacks of severe, short, sharp, stabbing pain affecting one or more branch of the nerve.  Most excruciating pain known (?)  Caused by inflammation of nerve  In severe cases, nerve is cut; relieves agony but results in loss of sensation on that side of the face CRANIAL NERVES 19
  • 20. TESTING TRIGEMINAL NERVE o Sensation- o Checked by extroceptive modalities like superficial pain, thermal, light touch over jaw, cheeks, and forehead. o Motor examination- o Muscle power of masticatory muscle namely the masseter and temporalis. o Inability to raise, depress, protrude, retract and deviate the mandible o Jaw deflected toward same side CRANIAL NERVES 20
  • 21. TESTING TRIGEMINAL NERVE  Jaw jerk- o Ask the patient to relax jaw. Place finger on the chin and tap it with hammer. o closing of mouth is the response o Brisk is normal o Exaggerated is pathological ◦ Corneal reflex- o Cornea is touched with wisp of wet cotton o Response is closing of both eyes o Afferent- ophthalmic div of VI nerve o Efferent- Facial nerve CRANIAL NERVES 21
  • 22. CN VII- FACIAL NERVE  ORIGIN: Pons & medulla.  INNERVATION: Anterior two-thirds of tongue; facial muscles, scalp, ear, and neck.  FUNCTION:  Control of facial muscles (expressions)  Motor limb of blink & corneal reflex  Secretion of salivary & lacrimal glands  Sensation of taste, anterior two-thirds tongue. CRANIAL NERVES 22
  • 23. CN VII- FACIAL NERVE(cont..)  Motor- ◦ Facial asymmetry - Ipsilateral weakness/paralysis, right or left, indicative of damage to motor nucleus or peripheral component (lower motor neuron lesion) EX: Bell's palsy ◦ Contralateral weakness/paralysis of lower face indicative of Contralateral motor cortex damage (upper motor neuron lesion) or hemispheric lesion, i.e. massive CVA. ◦ Bilateral weakness or paralysis , E.g. myasthenia gravis or Guillian Barre.  Parasympathetic- ◦ Loss or excessive tearing or salivation • Sensory- ◦ Loss of taste from anterior 2/3  Combined problem- ◦ speech difficulty and drooling/difficulty handling food CRANIAL NERVES 23
  • 24. CN VII- FACIAL NERVE(cont..)  CLINICAL EVALUATION o MOTOR FUNCTION: o Observe for facial symmetry o Flattening of nasolabial fold o Ask patient to wrinkle forehead, puff cheeks, smile, show teeth, close eyes against resistance, and whistle. o Wrinkle forehead- Frontalis o Close eye- orbi oculi o Purse lip- Buccinator o Show teeth- Orbi oris CRANIAL NERVES 24
  • 25. CN VII- FACIAL NERVE(cont..)  SENSORY FUNCTION: • Test each side of tongue separately. • Test for sweet (tip of tongue); sour (sides of tongue); salty (over most of tongue, but concentrated on sides). • Give sip of water between tastes. • Prevent flowing it to the posterior aspect of tongue • Reflex- • Corneal reflex • Glabellar reflex- Parkinson's disease CRANIAL NERVES 25
  • 26. CN VII- FACIAL NERVE(cont..) Guess your observation CRANIAL NERVES 26
  • 27. BELLS PALSY • Bell’s palsy: paralysis of facial muscles on affected side and loss of taste sensation • Caused by herpes simplex I virus, trauma, • Lower eyelid droops • Corner of mouth sags • Eye cannot be completely closed (dry eye may occur) • Lacrimation is seldom affected • Condition my disappear spontaneously without treatment  Bells phenomenon- Upward and outward movement of eye CRANIAL NERVES 27
  • 28. CN VIII – VESTIBULOCOCHLEAR NERVE  ORIGIN: Pons and medulla  INNERVATION: ◦ Cochlear - ear ◦ Vestibular - ear  FUNCTION: ◦ Cochlear - Hearing ◦ Vestibular - Balance, maintenance of body position, and proprioception. ◦ Rule out for presence of wax, pus, blood or foreign body Before testing CRANIAL NERVES 28
  • 29. COCHLEAR NERVE  Rinne’s test- ◦ For comparing bone and air conduction ◦ Tuning fork placed at the mastoid till the sound stop being heard ◦ Then is placed in front of ear to be tested ◦ +ve Rinne test i.e. air and bone both are retained ◦ -ve Rinne test i.e. air is lost but bone is retained(conductive deafness) ◦ If both are lost i.e. sensorineural deafness ◦ BERA TEST CRANIAL NERVES 29
  • 30. COCHLEAR NERVE(cont..)  Weber's test- ◦ Evaluates lateralization ◦ Use vibrating tuning fork on top of patient's head, ask patient where he hears it (one or both sides). ◦ Normally heard equally on both the sides ◦ If one ear is occluded then it acts like a resonating chamber and hear more on that side ◦ Conductive deafness- involved side ◦ Sensorineural- Uninvolved side CRANIAL NERVES 30
  • 31. VESTIBULAR NERVE  Look for Vertigo, Nystagmus, loss of balance  NYLEN-BARANY MANEUVER ◦ Patient lie down supine with head off the bed ◦ 45 degree extended ◦ Lateral flexion to the same side produces Nystagmus • Other tests are • caloric test(cows) • Galvanic test • Rotation test CRANIAL NERVES 31
  • 32. CN VIII – VESTIBULOCOCHLEAR NERVE  DYSFUNCTION (Cochlear) ◦ Unilateral deafness ◦ Loss of sound appreciation ◦ Tinnitus ◦ (Rinne Test) AC >BC is normal ◦ both diminished indicative of nerve damage ◦ BC> AC middle ear disease. ◦ (Weber Test) ◦ Lateralization to good ear is nerve damage, ◦ lateralization to bad ear is, middle ear CRANIAL NERVES 32
  • 33. CN VIII – VESTIBULOCOCHLEAR NERVE  DYSFUNCTION (VESTIBULAR) ◦ Vertigo ◦ Balance disturbances  Vestibular branch normally not tested unless patient gives history of vertigo or balance Disturbance history is positive, caloric testing is done by physician. CRANIAL NERVES 33
  • 34. CN IX- GLOSSOPHARYNGEAL NERVE  ORIGIN- ◦ Medulla  INNERVATION: ◦ Mucous membranes of tonsils, pharynx, posterior one-third of tongue, pharyngeal muscles, carotid sinus and carotid body  FUNCTION: ◦ Taste from posterior one- third of tongue - Afferent limb of gag, swallow, and cardiac reflexes. • DYSFUNCTION: ◦ Loss of taste; Neuralgia CRANIAL NERVES 34
  • 35. CN X – VAGUS NERVE ORIGIN- ◦ Medulla  INNERVATION: ◦ Muscles of larynx, pharynx, and soft palate. ◦ Parasympathetic innervation of thoracic and abdominal viscera.  FUNCTION: ◦ Muscles of larynx, pharynx, and soft palate ◦ Sensation conveyed from the heart, lungs, digestive tract, carotid sinus, & carotid body ◦ Efferent limb of gag and swallow reflex • DYSFUNCTION: • Loss of gag & swallow reflex • Loss of carotid sinus • oculocardiac reflex; Dysphagia CRANIAL NERVES 35
  • 36. CN IX- GLOSSOPHARYNGEAL and CN X - VAGUS  POSSITIVE FINDINGS-  Evaluate voice quality (hoarseness or dysarthria)  Ask patient to open mouth, say "ah", observe for elevation of soft palate, midline position of uvula.  Gag reflex, bilaterally  Swallowing  Taste (bitter) posterior one- third tongue CRANIAL NERVES 36 CN IX and X considered jointly, actions are seldom compared separately; they are always tested together.
  • 37. CN IX- GLOSSOPHARYNGEAL and CN X - VAGUS  Negative Findings  Loss of voice quality, (dysarthria or hoarseness)  Deviation of uvula toward non-paralyzed side  Swallowing difficulty or nasal regurgitation  Vagal irritation (bradycardia) CRANIAL NERVES 37
  • 38. CN XI - SPINAL ACCESSORY NERVE  ORIGIN: Medulla  INNERVATION: Sternocleidomastoid & trapezius muscles  FUNCTION: Motor function Sternocleidomastoid & trapezius  DYSFUNCTION: Muscle weakness. CRANIAL NERVES 38
  • 39. CN XI - SPINAL ACCESSORY NERVE • CLINICAL EVALUATION • Palpate trapezius muscle as patient shrugs shoulders against resistance; evaluate strength. • Ask patient to turn head to one side and push against examiners hand or ask to flex head against resistance, palpate and evaluate strength of sternocleidomastoid muscle. • Evaluate both right and left side, compare for symmetry. CRANIAL NERVES 39
  • 40. CN XII –HYPOGLOSSAL NERVE ORIGIN: Medulla  INNERVATION: Muscles of the tongue except palatoglossus  FUNCTION: Movement of the tongue  DYSFUNCTION: ◦ Unilateral lesions can cause paresis, atrophy, furrowing, fibrillation and fasciculation on the affected half ◦ On protrusion tongue deviates towards the affected side due to unopposed action of the Contralateral GENIOGLOSSUS  Flaccid paralysis ◦ Dysphagia ◦ Dysarthria ◦ Dyspnea ◦ Difficulty chewing food CRANIAL NERVES 40
  • 41. PUPILLARY REFLEX  Afferent- Optic  Efferent- Oculomotor  Yes(T)  Yes(O)  No(T)  No(O)  Yes(T)  No(O)  No(T)  Yes(O) CRANIAL NERVES 41 Normal Testing side- A and E = +nt Opposite side- E +nt Probable lesion in A of eye being checked Probable lesion in E of Opposite eye Lesion of E on same side and E of opposite eye is normal  Afferent- Optic  Efferent- Oculomotor  Yes(T)  Yes(O)  No(T)  No(O)  Yes(T)  No(O)  No(T)  Yes(O) Normal Testing side- A and E = +nt Opposite side- E +nt
  • 42. CORNEAL REFLEX CRANIAL NERVES 42 Normal Testing side- A and E = +nt Opposite side- E +nt Probable lesion in A of eye being checked Probable lesion in E of Opposite eye Lesion of E on same side and E of opposite eye is normal  Afferent-Trigeminal  Efferent- Facial  Yes(T)  Yes(O)  No(T)  No(O)  Yes(T)  No(O)  No(T)  Yes(O) Normal Testing side- A and E = +nt Opposite side- E +nt