Cranial Nerves Flashcards
Cranial nerve I
Olfactory nerve
Foramen in skull for olfactory nerve
Cribriform plate (ethmoid bone)
Origins of olfactory nerve
Olfactory cortex (temporal lobe)
Is the olfactory nerve sensory or motor
Sensory
Function of olfactory nerve
Sense of smell
Dysfunction of olfactory nerve
Altered/loss of sense of smell
Name of CN II
Optic nerve
Foramen in skull for optic nerve
Optic canal (sphenoid bone)
Origin of optic nerve
Visual cortex (occipital lobe)
Is the optic nerve sensory or motor
Sensory
Function of optic nerve
Sense of sight
Dysfunction of optic nerve
Altered/loss of vision
Name of CN III
Oculomotor nerve
Origin of oculomotor nerve
Midbrain
Foramen in skull that oculomotor passes through
Superior orbital fissure (sphenoid bone)
Type of fibres in oculomotor nerve
Motor and parasympathetic
Function of oculomotor nerve
Motor supply to extra-ocular muscles (LPS, SR, IR MR, IO)
Parasympathetic to the ciliary and constrictor pupillae muscles
Dysfunction of oculomotor nerve
Eye rests in down and out position
Ptosis
Mydriasis (dilated pupil)
Name of CN IV
Trochlear nerve
Foramen in skull that trochlear nerve passes through
Superior orbital fissure (sphenoid bone_
Which bone contains the superior orbital fissure
Sphenoid bone
Origin of trochlear nerve
Midbrain
Types of fibres in trochlear nerve
Motor
Function of trochlear nerve
Motor supply to superior oblique extra-ocular muscles
Dysfunction of trochlear nerve
Eye is unable to look down whilst adducted
Name of CN V
Trigeminal nerve
CN VI
Ophthalmic branch
Foramen ophthalmic branch passes through
Superior orbital fissure (sphenoid bone)
Origin of ophthalmic branch
Pons
Types of fibres in ophthalmic branch
Sensory
Function of ophthalmic branch
Sensation from upper 1/3 of face
Dysfunction of ophthalmic branch
Altered/absent sensation
CN V2
Maxillary branch
Foramen of maxillary branch
Foramen rotundum (sphenoid bone)
Origin of maxillary branch
Pons
Types of fibres in maxillary branch
Sensory
Function of maxillary branch
Sensation from middle 1/3 of face
Dysfunction of maxillary branch
Altered/absent sensation
CN V3
Mandibular branch
Foramen of mandibular branch
Foramen ovale (sphenoid bone)
Types of fibres in mandibular branch
Sensory and motor
Sensory Function of mandibular branch
Sensation from lower 1/3 of face
Motor function of mandibular branch
Motor to muscles of mastication
Motor to tensor tympani
Motor to some suprahyoid strap muscles
Dysfunction of mandibular branch
Altered/ absent sensation and weakness in mastication
Name of CN VI
Abducens nerve
Foramen for abducens nerve
Superior orbital fissure (sphenoid bone)
Origins of abducens nerve
Pons
Fibres in abducens nerve
Motor
Function of abducens nerve
Motor supply to lateral rectus extra-ocular muscle
Dysfunction of abducens nerve
Eye is unable to abduct
Which cranial nerves travel through the superior orbital fissure
Oculomotor
Trochlear
Ophthalmic branch of trigeminal nerve
Abducens nerve
Name of CN VII
Facial nerve
Foramen of facial nerve
Internal auditory meatus and then Stylomastoid foramen (temporal bone)
Origins of facial nerve
Pons
Types of fibres in facial nerve
Motor, sensory and parasympathetic
Motor function of facial nerve
Muscles of facial expression and stapedius
Sensory function of facial nerve
Sensation from ear canal
Taste to anterior 2/3 of tongue
Parasympathetic function of facial nerve
Submandibular and sublingual glands
Lacrimal glands
Dysfunction of facial nerve
Weakness/paralysis of facial muscles
Reduced salivatiom
Name of CN VIII
Vestibulocochlear nerve
Foramen of vestibulocochlear nerve
Internal auditory meatus (temporal bone)
Origins of vestibulocochlear nerve
Pons
Types of fibres in vestibulocochlear nerve
Sensory
Function of vestibulocochlear nerve
Provides sense of balance and hearing
Dysfunction of vestibulocochlear nerve
Vertigo
Tinnitus
Deafness
Which nerves pass through the internal auditory meatus
Facial nerve
Vestibulocochlear nerve
Name of CN IX
Glossopharyngeal nerve
Foramen of Glossopharyngeal nerve
Jugular foramen (temporal/occipital bone)
Origins of Glossopharyngeal nerve
Medulla
Which nerves originate in the midbrain
Oculomotor
Trochlear
Which nerves originate in the pons
Trigeminal
Abducens
Facial
Vestibulocochlear
Types of fibres in Glossopharyngeal nerve
Motor, sensory and parasympathetic
Motor function of Glossopharyngeal nerve
Motor to stylopharyngeus muscles
Sensory function of Glossopharyngeal nerve
Sensation from pharynx and posterior 1/3 of tongue
Sensation from carotid baroreceptors
Taste from posterior 1/3 tongue
Parasympathetic function of Glossopharyngeal nerve
Parasympathetic to parotid salivary gland
Dysfunction of Glossopharyngeal nerve
Loss of gag reflex
Reduced salivation
Name of CN X
Vagus nerve
Foramen of vagus nerve
Jugular foramen (temporal/occipital bone)
Origins of vagus nerve
Medulla
Types of fibres in vagus nerve
Motor, sensory and parasympathetic
Motor function of vagus nerve
Muscles of soft palate, pharynx and larynx
Which nerves are considered part of the central nervous system
Olfactory
Optic
Sensory function of vagus nerve
Sensation from ear canal
Taste from epiglottis
Parasympathetic of vagus nerve
Thoracic and abdominal organs
Dysfunction of vagus nerve
Loss of gag reflex
Absent rise of soft palate
Weak/absent cough/swallow
loss of parasympathetic to thoracic/abdominal organs
Name of CN XI
Accessory nerve
Foramen accessory nerve enters
Foramen magnum (occipital bone)
Foramen accessory nerve exits
Jugular foramen (temporal/occipital bone)
Origins of accessory nerve
Medulla
Fibres of accessory nerve
Motor
Function of accessory nerve
Motor to sternocleidomastoid and trapezius
Dysfunction of accessory nerve
Weakness in turning head and shrugging shoulders
Name of CN XII
Hypoglossal nerve
Foramen of Hypoglossal nerve
Hypoglossal canal (occipital bone)
Origins of Hypoglossal nerve
Medulla
Types of fibres in Hypoglossal nerve
Motor
Snellen chart
Letter chart used for testing eye sight
6/6 vision= can see at 6m
Function of Hypoglossal nerve
Intrinsic muscles of tongue
Dysfunction of Hypoglossal nerve
Weakness /paralysis of the tongue
Tongue deviates to affected side
Which nerves originate in the medulla
Glossopharyngeal
Vagus
Accessory
Hypoglossal
Which nerves go through the jugular foramen
Glossopharyngeal
Vagus
Accessory
Which nerves go through the internal auditory meatus
Facial
Vestibulocochlear
Where is the lateral geniculate nucleus located
Thalamus
Where is the Edinger-Westphal nucleus located
Midbrain
Pupillary light reflex involved which nerves and nuclei
Optic nerve
Edinger-Westphal nucleus
Oculomotor nerve
Primary function of superior oblique muscle
Intorsion
Corneal reflex
Sensation to cornea - ophthalmic nerve
Pons
Blink - facial nerve
Which nerve innervates muscles to blink/close eye
Facial nerve
Which nerve is sensory to cornea
Ophthalmic
Muscles involved in mastication
Lateral pterygoid
Medial pterygoid
Masseter
Temporalis
Main problem caused by facial nerve palsy
Dry eye- no tears
Where does the vestibulocochlear nerve (CN VIII) leave the CNS?
Pons
Which nerve provides the efferent pathway in the corneal reflex?
Facial nerve
Which nerve leaves the skull base via foramen rotundum?
Maxillary nerve V2
Which cranial nerve leaves the CNS from the posterior aspect of the brainstem?
Trochlear nerve
Gag reflex
Glossopharyngeal nerve
Medulla
Vagus
Which nerve provides motor innervation to the tensor tympani muscle?
Mandibular branch of trigeminal V3
Temporal, Buccal and Cervical are branches of which nerve?
Facial
Which cranial nerve provides the afferent pathway for the accommodation reflex?
Optic
Which nerve controls the muscle responsible for elevation of the eye whilst looking straight ahead?
Oculomotor
Which cranial nerve traverses foramen magnum?
Accessory
The glossopharyngeal nerve (IX) supplies which muscle?
Stylopharyngeus
The glossopharyngeal nerve (IX) supplies which muscle?
How to test cranial nerve II in an unconscious patient
Can be tested in the unconscious patient by observing pupillary constriction in response to light
Damage to CN V
Damage will result in the loss of the corneal reflex on the affected side
Disease of CN VIII
When diseased may cause rapid eye movements; nystagmus
Which nerves carry taste sensation
CN VII, IX, X
Which is the longest intracranial length of any of the cranial nerves
Trochlear nerve
Pupillary reflex afferent limb
Retino-hypothalamic tract
Pupillary reflex efferent limb
Oculomotor nerve
What runs through the cavernous sinus
Oculomotor nerve
Trochlear nerve
Abducens nerve
Ophthalmic nerve
Maxillary nerve
Internal carotid artery
Branches of facial nerve (CN VII) inside internal acoustic meatus
Greater petrosal nerve
Nerve to stapedius
Chorda tympani nerve
Greater petrosal nerve
Parasympathetic to lacrimal gland, sphenoid sinus, frontal sinus, maxillary sinus, ethmoid sinus and nasal cavity
Special sensory taste fibres to the palate via Vivian nerve
Which nerve supplies the sinuses
Greater petrosal nerve (branch of facial nerve)
Which nerve supplies special sensory taste fibres to palate
Vivian nerve
Nerve to stapedius
Motor innervation to Stapedius muscle in middle ear
Chorda tympani nerve
Parasympathetic innervation to submandibular gland and sublingual gland
Special sensory taste fibres for anterior 2/3 of tongue
Branches of facial nerve outside skull (distal to Stylomastoid foramen)
Posterior auricular nerve
Temporal
Zygomatic
Buccal
Marginal mandibular
Cervical
Posterior auricular nerve
Controls movements of some scalp muscles around the ear
Branch to posterior belly of digastric and stylohyoid muscle
5 major branches of facial nerve in parotid gland
Temporal
Zygomatic
Buccal
Marginal mandibular
Cervical
Katie, a 90 year old women, has many regrets in life. Thinking back to her university years of how she should have taken medicine instead of chemistry often gets her in a low mood. One day, In a fit of rage, she decides to scooter to the library and opens a Grays anatomy textbook onto a page about cranial nerves.
Which cranial nerves contain parasympathetic fibres?
CN3, CN7, CN9, CN10