Cranial Nerves Flashcards by ana thompson

what is the name of CNI?

Olfactory

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what is the pathway of the olfactory nerves?

receptors in olfactory epithelium of nasal cavity, olfactory nerve fibres pass through foraminifera in cribriform plate of ethmoid bone and enter olfactory bulb in the anterior cranial fossa

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what are the components of the olfactory nerves?

special sensory - smell

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what is the clinical application of the olfactory nerves?

fractured cribriform plate may tear olfactory nerve fibres causing anosmia

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what is the name of CNII?

optic

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what is the pathway of the optic nerves?

enters via optic canal, nerves join to form optic chiasm, fibres from medial (nasal) half of each retina cross to form optic tract

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what are the components of the optic nerves?

special sensory - vision

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what is the clinical application of the optic nerves?

increase in CSF pressure can cause papilloedema
section of right optic nerve causes blindness through right eye
section of optic chiasm causes loss of peripheral vision
section of right optic tract causes blindness in left temporal and right nasal fields

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what is the name of CNIII?

oculomotor

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what is the pathway of the oculomotor nerves?

emerges from midbrain and exits via superior orbital fissure

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what are the components of the oculomotor nerves?

somatic motor - extraocular muscles (except SO) and eyelid
visceral motor - parasympathetic to pupil causing constriction and to ciliary muscle causing accommodation of the lens

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what is the clinical application of the oculomotor nerves?

drooping of upper eyelid (ptosis)
eyeball abducted and pointing down
no pupillary reflex
no accommodation of the lens

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what is the name of CNIV?

Trochlear

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what is the pathway of the trochlear nerves?

emerges from dorsal surface of the mid brain and exits via the superior orbital fissure

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what are the components of the trochlear nerves?

somatic motor - extraocular muscle (superior oblique turns eye downwards)

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what is the clinical application of the trochlear nerves?

diplopia when looking down

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what is the name of CNV1?

Trigeminal (ophthalmic)

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what is the pathway of the ophthalmic nerves?

emerges from the pons, travels through the trigeminal ganglion and exits via the superior orbital fissure

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what are the components of the ophthalmic nerves?

General sensory - from cornea, forehead, scalp, eyelids, nose and mucosa of nasal cavity and sinuses

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what is the name of CNV2?

Trigeminal (maxillary)

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what is the pathway of the maxillary nerves?

emerges from the pons, travels through the trigeminal ganglion and exits via the foramen rotundum

what are the components of the maxillary nerves?

General sensory - from face over maxilla, maxillary teeth, temperomandibular joint, mucosa of nose, maxillary sinuses and palate

what is the name of CNV3?

Trigeminal (mandibular)

what is the pathway of the mandibular nerves?

emerges from the pons, travels through the trigeminal ganglion and exits via the foramen ovale

what are the components of the mandibular nerves?

General sensory - from face over mandible, mandibular teeth, temperomandibular joint, mucosa of mouth & anterior 2/3rds of tongue Somatic motor - muscles of mastication, part of digastric, tensor veli palatinin & tensor tympani

what is the clinical application of the mandibular nerves?

paralysis of muscles of mastication loss of corneal or sneezing reflex loss of sensation in the face trigeminal neuralgia

what is the name of CNVII?

facial

what is the pathway of the facial nerves?

emerges between pons and medulla and exits via internal acoustic meatus, facial canal and stylomastoid foramen

what are the components of the facial nerves?

somatic motor - muscles of facial expression & scalp, stapedius of middle ear, part of digastric muscle visceral motor - parasympathetic innervation of submandibular & sublingual salivary glands, lacrimal glands, glands of nose & palate special sensory - taste from anterior 2/3rd of tongue & soft palate general sensory - from external acoustic meatus

what is the clinical application of the facial nerves?

most frequently injured - due to long pathway through bone | Bell’s palsy - cannot frown, close eyelid, or bare teeth

what is the name of CNVIII?

Vestibulocochlear

what is the pathway of the vestibulocochlear nerves?

emerges from between pons and medulla and exits via internal acoustic meatus, dividing into vestibular & cochlear nerves

what are the components of the vestibulocochlear nerves?

special sensory - vestibular sensation from semicircular ducts, utricle, saccule gives sense of position & movement hearing from spiral organ

what is the clinical application of the vestibulocochlear nerves?

tinnitus (ringing in the ears) deafness (conductive vs sensorineural) vertigo (loss of balance) nystagmus (involuntary rapid eye movements)

what is the name of CNIX?

glossopharyngeal

what is the pathway of the glossopharyngeal nerves?

emerges from medulla and exits via jugular foramen

what are the components of the glossopharyngeal nerves?

special sensory - taste from posterior 3rd of tongue general sensory - cutaneous sensations from middle ear and posterior oral cavity visceral sensory - sensation from carotid body & carotid sinus visceral motor - parasympathetic innervation of parotid gland somatic motor - to stylopharyngeus, helps with swallowing

what is the clinical application of the glossopharyngeal nerves?

loss of gag reflex and taste from back of tongue | associated with injuries to CNs X and XI - jugular foramen syndrome

what is the name of CNX?

vagus

what is the pathway of the vagus nerves?

emerges from medulla and exits via jugular foramen, then everywhere!

what are the components of the vagus nerves?

special sensory - taste from epiglottis and palate general sensory - sensation from auricle, external acoustic meatus visceral sensory - from pharnyx, larynx, trachea, bronchi, heart, oesophagus, stomach, intestine visceral motor - parasympathetic innervation muscle in bronchi, gut, heart somatic motor - to pharynx, larynx, palate & oesophagus

what is the clinical application of the vagus nerves?

damage to pharyngeal branches cause difficulty in swallowing | damage to laryngeal branches causes difficulty in speaking

what is the name of CNXI?

accessory

what is the pathway of the vagus nerves?

small cranial (medulla) and large spinal roots exit via jugular foramen

what are the components of the vagus nerves?

somatic motor - striated muscle of soft palate, pharynx & larynx, and to sternocleidomastoid & trapezius

what is the clinical application of the vagus nerves?

weakness in turning head and shrugging shoulder

what is the name of CNXII?

hypoglossal

what is the pathway of the hypoglossal nerves?

emerges from medulla and exits through the hypoglossal canal

what are the components of the hypoglossal nerves?

somatic motor - to muscles of tongue

what is the clinical application of the hypoglossal nerves?

vulnerable to damage during tonsillectomy | causes paralysis & atrophy of ipsilateral half of tongue. Tip deviates towards affected side