Clinical Cranial Nerve Testing Flashcards
Clinically Relevant anatomy of cranial nerve testing.
Olfactory Nerve is
special sensory
Optic nerve is
special sensory
Oculomotor nerve is
motor and parasympathetic
Trochlear nerve
is motor
Trigeminal Nerve is
V1+2 are sensory only, V3 is sensory and motor.
Abducent nerve is
motor
Facial nerve is
special sensory, motor and parasympathetic.
Vestibulocochlear is
Special sensory
Glossopharyngeal is
special sensory, sensory, motor and parasympathetic.
Vagus nerve is
sensory, motor, parasympathetic and visceral afferent.
Spinal accessory nerve is
motor
Hypoglossal nerve is
motor.
Cranial nerves from the midbrain
Oculomotor and trochlear
Cranial nerves from the pons
V1,2,3
The cranial nerve from the pontomedullary junction
Abducens, facial, and vestibulocochlear.
Cranial nerves from the medulla oblongata
Glossopharyngeal, vagus, hypoglossal.
The spinal nerve from the spinal cord
Spinal accessory.
The olfactory nerve leaves the skull via
The cribriform plate of the ethmoid.
Base of skull fracture can lead to anosmia T/F
T - can be regained as olfactory nerves grow back
Only cranial nerve found in the anterior cranial fossa?
Olfactory nerve
The optic nerve goes through the
Optic canal
Course of optic nerve
Optic nerve goes through the optic canal in the middle cranial fossa. It travels around the pituitary stack to the optic chiasm, to form the optic tract. Connect to the CNS via the diencephalon.
5 Ways to test the optic nerve
Acuity (Snellen charts), colour (Ishihara plates - colour blindness), fields (four quadrants), reflexes (pupillary light reflexes), fundoscopy.
Nerves that go through the superior orbital fissure
Oculomotor, trochlear, abducens. Frontal, lacrimal and nasocilliary branches of V1.
How to test CNIII parasympathetics?
Use a light to check for pupillary contraction.
Trochlear nerve supplies the
superior oblique muscle.
Abducent nerve supplies the
Lateral rectus muscle
The abducents nerves travel through the
cavernous sinus and the superior orbital fissure.
The vestibulocochlear nerve travels through which cranial foramen
Internal aucoustisc meatus, in the posterior cranial fossa
Clinically testing of vestibulocochlear nerve
Rinnie and Weber.
The spinal accessory nerve supplies the
Sternocleoidmastoid and the trapezius.
The cranial fossa that the spinal accessory nerve travels through is the
It ascends through the foramen magnum and then travels to the jugular foramen in the posterior fossa to innervate the SCM and trapezius.
Clinical testing of the spinal accessory nerve
Ask patient to shrug shoulders. Ask them to turn head to flex neck and turn towards the opposite side.
The hypoglossal nerve goes through which cranial foramen
Hypoglossal canal in the posterior fossa
The hypoglossal nerve passes anterior to the carotid sheath TF.
F - the hypoglossal nerve passes lateral to the carotid sheath. At the level of the hyoid it turns anteriors towards to the lateral aspects of the tongue.
The hypoglossal supplies which tongue muscles?
Genioglossus, styloglossus, hypoglossus, and intrinsic muscles of the tongue.
What tongue muscle does the hypoglossal nerve NOT supply?
Palaoglossus - supplied by the vagus.
Clinical testing of the hypoglossal
Ask patient to stick tongue straight out. Both CNXIIs are functioning normally the tongue remains in the midline. If there is unilateral CN XII pathology the tongue tip will point towards the side of the injured nerve.
What are the divisions of the trigeminal
V1 - ophthalamic - sensory
V2 - Maxillary - sensory
V3 - Mandibular - motor and sensory
Nerve that passes though the foramen rotundom
V2
Nerve that passes thought he foramen ovale
V3
CN V1 supplies the
Upper eyelid, cornea, all the conductive, skin of the root/bridge/tip of the nose.
Paranasal sinuses, anterior and posterior cranial fossa.
Hutchison’s sign
Herpes zoster of V1 - rash at the tip of the nose.
Lower posterior nasal cavity, maxilla and maxillary sinuses, floor of the nasal cavity/palate. Maxillary teeth and soft tissues(gingival and mucosal).
CN V2 supplies the
Skin of the lower eyelid, skin over the maxilla, skin of the ala of the nose, skin/mucosa over the upper lip.
CN V3 supplies sensation to
The skin over the mandible and temporomandibular joint. Except the angle of the mandible.
Middle cranial fossa, mandible, anterior 2/3rds of the tongue, floor of mouth, buccal mucosa, mandibular teeth.
Nerves that supply the angle of the mandible and some of the external ear
Great auricular nerve of C2,3.
What can cause loss of sensation around teeth
Disruption of the foramen rotundum.
Motor innervation of V3
Muscles of mastication - master, temporals, medial pterygoid, lateral pterygoid.
Tensor veli palatini. Tensor tympani.
Facial nerve goes through which cranial foramen
Internal acoustic meatus in the posterior fossa.
The facial nerve exits the skull via the
Stylomastoid foramen.
It goes through the IAM and then into the facial canal of the petrous temporal bone (to give off chords tymapni and supply stapediues) and then (motor component) exits via the stylomastoid foramen.
What is the chorda tympani and what does it do?
Branch of the facial. Supplies the taste buds of the anterior 2/3rds of the tongue.
Parasympathetic supply to the submandibular and sublingual glands (salivation).
Nerve supply to the stapedius muscle
Supplies by facial, reduces stapes movement to protects the internal ear from excessive noise.
Muscles of facial expression
Frontalis, orbicularis occult, elevators of lips, orbicularis oris.
Clinically testing the facial nerve
Raise the eyebrows, close eyes tightly, smile, puff out cheeks and hold air.
Glossopharyngeal goes through which cranial foramen
Jugular foramen.
Special sensory functions of the glossopharyngeal
The valuate papillae - taste buds of posterior 1/3rd of tongue.
Parasympathetic functions fo glossopharyngeal
Secretomotor - to the parotid gland (salivary).
General sensory of the glossopharyngeal
The posterior 1/3rd of the tongue, mucosa of most of nasopharynx and oropharynx. Some mucosa o laryngopharynx. Palatine tonsils, eustachine tube, middle ear cavity.
Nerve responsible for referred pain from pharynx to ear and vice versa
Glossopharyngeal
The general sensory axons of this nerve form the afferent limb of the gag reflex.
Glossopharyngeal nerve.
Visceral afferent nerves to the carotid sinus baroreceptors and the carotid body receptors.
Glossopharyngeal nerve
Somatic motor innervation of glossopharyngeal.
Stylopharyngeus.
Exists cranial cavity via
jugular foramen.
CN X runs lateral to the carotid sheath TF
F - the vagus runs within the carotid sheath.
Left recurrent laryngeal nerve curves under the ____ _______
Arch of the aorta
Right recurrent laryngeal curves under the __________
Right subclavian
The recurrent laryngeal nerve is a branch of the
Vagus!
The vagus nerve passes posterior to lung root and onto the oesphagus TF
T
Vagus nerve testing
Ask patient to say Ahhhhhh. (tests muscles of palate) Uvula should lift straight in midline, unilateral pathology will pull uvula away from non-functioning side.
You ask the patient to say aaaa and observe the uvula is pointed away from the midline towards the right. What side is the pathology on?
Left
You ask the patient to stick their tongue out and observe that it is pointed away from he midline towards the left. What side is the pathology on?
Left
By asking the patient to swallow a small amount of water what muscles and cranial nerve are you testing?
Pharyngeal, vagus.
Splutter may suggest abnormal swallow.
Hoarse voice may suggest what?
Abnormal function of muscles of larynx, and recurrent laryngeal.
