Clinical anatomy of cranial nerves Flashcards
What runs in the cribriform plate of the ethmoid bone?
Olfactory nerve
What is the contents of the optic canal of the sphenoid bone?
Optic nerve and the ophthalmic artery
In what bone is the superior orbital fissure?
Sphenoid
What runs in the SOF?
Lacrimal nerve CN V1 Superior ophthalmic vein CN 4 CN 3 CN 6 Inferior ophthalmic vein
What runs in the foramen rotundum?
Maxillary nerve
What runs in the foramen ovale?
Mandibular nerve
What runs in the internal acoustic meatus?
Facial nerve
Vestibulocochlear nerve
Vestibular ganglion
Labyrinthe artery
What runs in the jugular foramen?
Inferior petrosal sinus
Glossopharyngeal nerve, vagus nerve and spinal accessory nerve
Sigmoid sinus
In what bone is the internal acoustic meatus?
Petrous part of temporal bone
In what bone is the hypoglossal canal?
Occipital bone
What runs in the hypoglossal canal?
Hypoglossal nerve
What runs in the foramen magnum?
Medulla Meninges Vertebral arteries Anterior and posterior spinal arteries Dural veins
What runs in the foramen spinosum?
Middle meningeal artery
Where will the optic nerve connect with the CNS?
Diencephalon at the lateral geniculate nucleus where it will then radiate to the visual cortex at the occipital lobe
How can the optic nerve be tested?
Acuity - snellen Colour - ishihara Fields Reflexes Fundoscopy
Where does the oculomotor nerve originate?
Midbrain
What are the contents of the cavernous sinus?
Oculomotor nerve Trochlear nerve Ophthalmic branch of trigeminal nerve Maxillary branch of trigeminal nerve Internal carotid artery Abducens nerve
Where does the trochlear nerve originate?
Midbrain
Where does the abducens nerve originate?
Pontomedullary junction
How are CN 3,4 and 6 tested?
H test - eye movements
Where does the vestibulocochlear nerve originate?
Pontomedullary junction
How is the vestibulocochlear nerve tested?
Rinne
Weber
Describe rinne and weber testing?
Rinne - hold infront of ear and then on mastoid. In conducive hearing loss, you will hear better when on mastoid whereas in sensorineural you will hear better in air
Weber - hold tuning fork on head - sensorineural it will lateralise to normal ear but in conduction it will go towards affected ear
Where does the spinal accessory nerve originate on the CNS?
Cervical spinal cord - top 4 segments
How is the spinal accessory nerve tested?
Shug shoulders = trapezius
Turn head to flex neck and turn head towards opposite side
Where does the hypoglossal nerve connect with the CNS?
Via many rootlets lateral to the pyramids of the medulla oblongata
Where will the hypoglossal canal descend?
Lateral to the carotid sheath
At level of hyoid, tuns anteriorly towards lateral aspect of tongue
What is the medullary olive?
Inferior olive - cerebellar system
Superior orlive - pons and part of the auditory system, aiding the perception of sound
What innervates the palatoglossus muscle?
Vagus nerve
How is the hypoglossal nerve tested?
Stick tongue straight out
If there is unilateral pathology - the tongue tip will point towards the injured nerve
The Tongue tells the Truth
Which division of the trigeminal nerve provides sensory and motor innervation?
Only mandibular division
What part of the brain does the trigeminal nerve come off?
Pons
Where does the trigeminal nerve run in the brain?
Inferior to edge of tentorium cerebelli between post and middle cranial fossa
What type of neurones will the trigeminal sensory have?
Pseudounipolar = SENSORY NEURONES
What is the sensory distribution of CN V1?
Upper eyelid
Cornea (corneal reflex)
Conjunctiva
Skin of root/bridge/tip of nose
What is the sensory distribution of CN v2?
Skin of lower eyelid
Skin over maxilla
Skin over ala of nose
Skin of upper lip
What is the sensory distribution of CN V3?
Skin over mandible and TMJ
What supplies the angle of the mandible?
Greater auricular nerve; C2,3
What is the deep sensory territory of V1?
Bones and soft tissues of orbit
Upper anterior nasal cavity
Paranasal sinuses except the maxillary sinus
Anterior and posterior cranial fossa
What is the deep sensory territory of V2?
Lower posterior nasal cavity
Maxilla and maxillary sinus
Floor of nasal cavity/ palate
Maxillary teeth and assoc soft tissues
What is the deep sensory territory of V3?
Middle cranial fossa Mandible Anterior 2/3rds of tongue Floor of mouth Buccal mucosa Mandibular teeth
What is the CN V3 motor supply?
Masseter Temporalis Medial Pteygoid Lateral pteygoid Tensor veli palatini Tensor tympani
Where does the facial nerve connect to the CNS?
Pontomedullary junction
What is the course of somatic motor facial nerve axons?
Pass through internal acoustic meatus and then through the stylomastoid foramen
Pass into the parotid gland to then supply muscles of facial expression
What is the action of the chorda tympani?
Taste buds to anterior 2/3rds of tongue
Parasymp to submandibular and sublingual glands
What muscle in the inner ear does the facial nerve supply?
Stapedius muscle
What is the function of the lingual nerve?
V3 to supply general sensation to the anterior 2/3rds of the tongue
What are the muscles of facial expression?
Frontalis
Orbicularis oris
Elevators of lips
Orbicularis oculi
Where does the glossopharyngeal nerve originate on the CNS?
Medulla oblongata
What is the general sensory actions of the glossopharyngeal nerve?
Posterior 1/3rd of tongue Mucosa of most of nasopharynx and oropharynx Mucosa of some of laryngopharynx Palatine tonsil Eustachian tube Middle ear cavity
What is the special sensory action of the glossopharyngeal nerve?
Vallate papillae on post 1/3rd of tongue
What is the parasymp action of the glossopharyngeal nerve?
Parotid gland
What are the visceral afferent actions of the glossopharyngeal nerve?
Carotid sinus
Baroreceptors
Carotid body chemoreceptors
What is the somatic motor action of the glossopharyngeal nerve?
Stylopharyngeus
Where does the vagus nerve connect with the CNS?
Medulla oblongata
Where will the vagus nerve run within the neck?
Within the carotid sheath
Posterior to and between the common carotid artery and internal jugular vein
Describe the differences between the left and right recurrent laryngeal nerves?
Left hooks under arch of aorta
Right hooks under right subclavian
