Describe the pathway and components of CN I [3]
Type of nerve fiber [1]
- Olfactory Nerve
- Purely Special Sensory (smell)
Fibres start in receptors in the olfactory epithelium of the nasal cavity [1]
- -> Pass through foramina in the cribriform plate of the ethmoid [1]
- -> Enters the olfactory bulb and goes to primary olfactory area in temporal lobe [1]
Whats the clinical relevance of the 1st cranial nerve? [2]
If you fracture the cribriform plate [1] you can tear the olfactory nerve fibres causing anosmia [1]
Describe the pathway and components of the 2nd cranial nerve [6]
Type of nerve fiber [1]
- Optic Nerve
- Purely Special Sensory (Vision)
- Retinal Nerve Fibres
- > Optic Disc -> Optic Nerve (in optic canal)
- > Fibres mix at the optic chiasm and nasal fibres swap sides. So temporal fibres and contralateral nasal fibres of each side form optic tracts
- > Synapse at LGB
- > Form Right and Left Optic Radiations
- > Feed into the left and right Primary Visual Cortex
Whats the clinical relevance of Cr N II [2]
Papilloedema (Optic Disc Swelling
- Due to increased Intracranial Pressure
Transection of various points along the visual pathway can lead to different patterns of blindness
What could cause damage to the optic chiasm? [1]
Pressure from a Pituitary Tumour
What are the components of the 3rd cranial nerve? [2]
Oculomotor:
- Somatic Motor supply to most of the extraocular muscles
- Autonomic Motor (parasympathetic) to the constrictor pupillae and the ciliaris muscle
What extraocular muscles arnt supplied by the oculomotor nerve? [2]
- Sup Oblique (Cranial Nerve IV - Trochlear)
- Lateral Rectus (Cranial Nerve VI - Abducens)
Whats the pathway of the 3rd cranial nerve through the skull [2]
- Arises from midbrain- pontine junction
- Emerges throught he superior orbital fissure
Whats the clinical relevance of the oculomotor nerve? [4]
Ptosis
- Loss of somatic innervation to the levator palpebrae Superioris
Eyeball Abducted & Depressed:
- Due to loss of innervation to the extraocular muscles so the sup oblique depresses it and the lateral rectus abducts it
Loss of pupillary reflex
- Loss of autonomic motor innervation
No lens accommodation
- Loss of autonomic motor innervation
What are the components of the 4th cranial nerve? Type of nerve fibre [1]
Its Purely Somatic Motor to the superior oblique
Describe the pathway of the 4th cranial nerve through the skull? [2]
Comes from the midbrain and emerges through the superior orbital fissure
Clinical relevance of the trochlear nerve? [4]
Lose innervation to the sup oblique [1] so when you look down [1] one eye doesnt depress properly [1] leading to diplopia [1]
Describe the pathway of the 5th cranial nerve [6]
Emerges from pons [1] and forms the trigeminal ganglion [1], then it divides into the 3 branches [1]
- Ophthalmic exits via Sup Orbital Fissure
- Maxillary exits through Foramen Rotundum
- Mandibular Exits through the Foramen Ovale
Whats the components of the trigeminal nerve branches? [4]
Describe the type of nerve fibre for each component
Ophthalmic V1
- General Sensory to cornea/eyelid/scalp/nose/nasal&sinus mucosa
Maxillary V2
- General Sensory to face, upper teeth, TM joint, palate and nose
Mandibular V3
- General Sensory to face, lower teeth, TM joint, mouth mucosa & ant 2/3rds of tongue
- Somatic Motor to muscles of mastication, digastric, tensor veli palatine & Tensor Tympani
Whats the clinical relevance of the trigeminal nerve? [4]
- Paralysed Muscles of mastication
- Loss of corneal or sneezing reflex
- Loss of facial sensation
- Trigeminal Neuralgia
Describe the pathway [2] components [1] and clinical relevance of the 6th cranial nerve [2]
Components: What type of nerve fibre is it made of?
- Abducens
- Emerges from between pons & Medulla then out via the Sup Orbital Fissure
- Components: Contains purely somatic motor nerves to the lateral rectus
- Loss of this nerve leads to medial deviation [1] of the eye and diplopia [1]
What are the components of the facial nerve CN7? [4]
Somatic Motor
- Muscles of facial expression, stapedius & Digastric
Autonomic Motor
- Salivary Glands (not parotid)
- Lacrimal glands
- Other glands in the nose/palate
Special Sensory:
- Taste to Ant 2/3rds of tongue
General Sensory
- External Acoustic Meatus
Whats the pathway of the facial nerve? [4]
Emerges from between Pons & Medulla [1]
Then exits via the internal acoustic meatus [1] through the facial canal [1] and out stylomastoid foramen [1]
Whats the clinical relevance of Cranial Nerve VII [1]
- Damage leads to facial palsies
E.g. Bell’s Palsy where you cant frown, close your eyelid or bare teeth on one side
Whats the pathway of the 8th cranial nerve? [3]
Vestibulocochlear nerve
Emerges from between Pons and Medulla [1]
Exits through internal acoustic meatus [1]
Divides into Vestibular and Cochlear nerves in the middle ear [1]
What are the components of the vestibulocochlear nerve? [1]
Special Sensory
Clinical relavance of the 8th cranial nerve? [4]
- Tinnitus
- Sensorineural deafness
- Vertigo
- Nystagmus
Describe the pathway of the glossopharyngeal nerve? [2]
Emerges from the medulla
Exits via the jugular foramen
What are the components of the 9th cranial nerve? [5]
- Special Sensory to post 3rd of the tongue
- General Sensory to the middle ear and post oral cavity/post 3rd of tongue
- Visceral Sensory to carotid body/sinus
- Autonomic motor to the parotid gland
- Somatic Motor to the Stylopharyngeus (swallowing)
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Cells & Tissues25
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Cranial Nerves34
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Basic neuroanatomy 133
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Cerebrum54
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Spinal Tracts10
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Functional Hierarchy of the motor System16
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Vestibular Function34
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Motor 116
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Motor 210
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EEG & Sleep31
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Sleep Disorders11
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Memory & Cognition27
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Sensory Systems26
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Multiple Sclerosis40
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ANS Recap Session19
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Muscle & Nerve Disease52
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Spinal Cord Disease27
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Clinical Neurophysiology11
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Epilepsy68
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Headache41
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Meningitis/Encephalitis41
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NS Infection - Post Inflammatory Syndromes3
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Congenital Malformations21
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Pathophysiology of Pain23
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Pathology of Head Injury22
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CSF neuroanatomy6
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Lumbar Punctures24
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Hydrocephalus18
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Neurosurgical Clinical Assessment22
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Coma + PVS + Brain Death29
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Bits & Pieces5
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Stroke72
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Brain Tumours53
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Cranial Nerve Disorders29
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Functional Neurological Symptom Disorder13
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Cerebral Blood Flow & ICP32
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Neuroradiology22
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Diseases of Spinal Cord/Nerve Roots (Surgical)25
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Bits from Formative9
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Basal Ganglia disorders38
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Traumatic Brain Injury21
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Dermatomes and Myotomes25
