1-6 Cranial Nerves.pptx

Crainial Nerves 1_6 olfactory to abducent

1. CRANIAL NERVES

2. Cranial nerves are the  nerves  that emerge directly from the  brain  (including the  brainstem ), in contrast to  spinal nerves  (which emerge from segments of the  spinal cord ). Cranial nerves relay information between the brain and parts of the body, primarily to and from regions of the head and neck. The  terminal nerves ,  olfactory nerves  (I) and  optic nerves  (II) emerge from the  cerebrum  or forebrain, and the remaining ten pairs arise from the brainstem, which is the lower part of the brain.

3. CN

4. Number of Cranial Nerves There are 12 pair of Cranial Nerves. Olfactory I   Optic II   Oculomotor III Trochlear IV   Trigeminal V    Abducens VI    Facial VII    Auditory ( vestibulocochlear ) VIII    Glossopharyngeal IX    Vagus X    Spinal Accessory XI    Hypoglossal XII

5. OLFACTORY (Smell) This is a type of sensory nerve that contributes in the sense of smell in human being. These basically provide the specific cells that are termed as olfactory epithelium. It carries the information from nasal epithelium to the olfactory center in brain.

6. Olfactory Nerve Anosmia: it means loss of sense of smell. If due to neurological lesion It may be due to: Head injury Tumor of anterior cranial fossa . Tuberculous meningitis

7. Lesion Frontal lobe tumor Closed head injuries Nasal obstruction Viral infections Parkinsons disease Alzheimer’s Multiple Sclerosis

8. Parosmia : means perversion of smell Offensive smell is perceived as pleasant smells and vice versa. Psychogenic in nature. Hallucination of smell : These sometime occur in temporal lobe epilepsy.

9. Testing smell Ask the patient whether he can appreciate common smells Do not use irritating smells for test like ammonia. Test each nostril separately

10. Abnormal sign. Partial or total loss of smell. Altered or increased sense of smell.

11. Treatment Several medications, including sedatives, anti-depressants and anti-epileptic drugs, have been suggested to treat olfactory distortions.   If perception of the distortion can be blocked with nasal occlusion, one of the easiest things to try is topical nasal saline drops . The vast majority of individuals with olfactory distortions can be helped with the above therapies. Those who cannot may benefit from surgical therapies.

12. OPTIC (Vision) Optic nerve This is a type of sensory nerve that transforms information about vision to the brain. To be specific this supplies information to the retina in the form of ganglion cells.

13. 2. Optic Visual acuity : commonly refers to the clarity of  vision . the sharpness of the retinal focus within the eye,  Snellen chart

14. Color Ishara chart 8% of men and 0.5% of women have congenital X-linked color blindness Ask the patient to recognize various colors

15. Hemianopia . Lose of vision affecting one half of the visual field . Quadrantanopia : loss of one quadrant of the visual field. Visual inattention: patient can see normally when both sides are tested simultaneously, he ignores one side. Fundoscopy . Pupillary light reflex Direct & consensual response

16. Abnormal signs Visual field defects. Loss of visual acuity. Colour blind.

17. Optic Neuritis Optic neuritis is inflammation of the  optic nerve , caused by damage to and loss of the protective sheath ( myelin ) surrounding this nerve that is so vital for good vision. 

18. Treatment Steriods Prednisone

19. OCULOMOTOR (Eyelid and Eyeball Movement) This is a form of motor nerve that supplies to different centers along midbrain. Its functions include superiorly uplifting eyelid, superiorly rotating eyeball, construction of pupil on the exposure to light and operating several eye muscles.

20. MOTOR All the extra ocular muscles except superior oblique and lateral oblique. Lateral and medial recti (MR) move eyeball laterally and medially Superior rectus (SR) move eyeball laterally upward. Inferior rectus(IR) move eyeball laterally downward. Inferior rectus and superior oblique move eyeball downward. M edially downward and upward, SO and IO

21. Causes of dysfunction Vascular disorders Space occupying lesions or tumors, both malignant and non-malignant Inflammation and Infection Trauma Demyelinating disease (Multiple sclerosis) Autoimmune disorders such as Myasthenia gravis

22. Testing of III CN Movement of the eyeball and eyelid, constriction of pupil, lens accommodation Look for ptosis : ask the patient to follow your finger medially , laterally, downward, and laterally upward. Pupil size. Look for pupil size and reaction to light and accommodation. Light reflex: Accommodation reflex.

23. III-IV-VI Oculomotor , Trochlear & Abducent Muscles extra ocular & intraocular

24. Ocular movement. Nystagmus Dancing eyes Diplopia Ptosis R eactive to L ight and A ccommodation Accommodation reflex Convergence or divergence

25. Abnormal signs Squint. Ptosis . Diplopia . Pupil dilatation.

26. Third Nerve Palsy   A complete third nerve palsy causes a totally closed eyelid and misaiming of the eye outward and downward. The eye cannot move inward or up, and the pupil is typically enlarged and does not react normally to light. A partial third nerve palsy affects, to varying degrees, any of the functions controlled by the third cranial nerve.

27. Treatment Medical management is actually watchful waiting.   Nonsteroidal anti-inflammatory drugs (NSAIDs ) C ondition is expected to resolve spontaneously within a few weeks

28. Physiotherapy Treatment Pencil Push-Up Therapy To do pencil push-ups, sit down with your favorite pencil handy. Hold the pencil in front of your face at a distance that you can clearly see the letters written on the side of the pencil. Slowly move the pencil toward your nose. Your goal is to choose one letter on the pencil and keep it in focus as you bring the pencil toward you. If the letter blurs or you see more than one, move the pencil further away. This exercise improves the ability of your eyes to cross and moves inwards, a common problem for people who experience double vision.

29. Swinging To do swinging, stand up and choose an object that is far away to stare at. Then, gently sway side to side and keep the object in focus as best as you can. Make sure you blink during the exercise.

30. Eye Rolling To do this exercise, sit down and look straight ahead. Roll your eyes clockwise. Then, roll them back counterclockwise and blink. Perform the desired number of repetitions.

31.  TROCHLEAR   This motor nerve also supplies to the midbrain and performs the function of handling the eye muscles and turning the eye .

32. IV Trochlear . MOTOR Superior oblique ( move eyeball medially downward) Testing of IV CN; ask the patient to follow your finger medially and then downward.

33. Treatment T ilting the head to side opposite the affected eye can eliminate them . Eye exercises Pencil Push Up Therapy Swinging Eye Rolling Prism glasses Eye exercises help, as may wearing prism glasses. The palsy usually resolves over time.

34. TRIGEMINAL This is a type of cranial nerve and performs many sensory functions related to nose, eyes, tongue and teeth. It basically is further divided in three branches that are ophthalmic, maxillary and mandibular nerve. This is a type of mixed nerve that performs sensory and motor functions in brain.

35. V-Trigeminal MOTOR . Muscle of mastication Motor testing. Clenches of teeth Jaw with resistance Side movement

36. SENSORY. Carries touch, pain and temperature sensation.. Sensation for eye, F ace, part of head, inside of mouth Sensory testing; C orneal reflex The  corneal reflex , also known as the blink reflex , is an involuntary blinking of the eyelids elicited by stimulation of the  cornea  (such as by touching or by a foreign body) Test facial sensation

37. Abnormal signs Trigeminal neuralgia Loss of mastication Sensation in eye, face, sinuses and teeth.

38. Treatment Carbamazepine, gabapentin, baclofen,  and  IV phenytoin  are the most effective treatments. Transcutaneous electrical nerve stimulation (TENS) Exercises

39. Abducent   This is again a type of motor nerve that supplies to the pons and perform function of turning eye laterally.

40. VI Abducent . Motor Lateral rectus.( move eyeball laterally or abduction). Control gaze. Testing of VI CN; ask the patient to follow your finger laterally.

41. Abnormal signs Gaze palsy.

42. Sixth Nerve Palsy Sixth cranial nerve palsy is weakness of the nerve that innervates the lateral rectus muscle.  The most common causes of 6 th  cranial nerve palsy are stroke, trauma, viral illness, brain tumor, inflammation, infection, migraine headache and elevated pressure inside the  brain.

43. Treatment Sixth nerve palsy has been known to resolve on its own, without treatment.  Corticosteroids P rism spectacles S trabismus surgery