Cranial Nerve Examination Flashcards
There are __ pairs of cranial nerves, all of which are innervated to musculature arise bilaterally from the same side from which they emerge, except for C.N. _______
12
VII (Facial- arises contralaterally)
Volitional movements from cranial nerves arise bilaterally from the ___________ of the cerebral motor cortex and descend along the ______________ of the brain
Precentral gyrus
Corticobulbar
________ refers to cortex while ____________ refers to the brain stem
Cortico = cortex Bulbar = brainstem
T/F Both the right and left hemisphere have control over the right and left parts of the body due to bilateral innervation
True
Alternate names for the neurons of the corticobulbar tract
Upper motor neurons
Supranuclear neurons
Upper motor neurons synapse with ____________ which form the synpatic link to the ____________ which go on to innervate specific muscles
Lower motor neurons (alpha-neurons)
Peripheral cranial nerves
Connections that have long thought to be responsible for some of the clinical relationships between headaches, dizziness, and the neck
- Vestibular cranial nerve nuclei
- Cervically innervated muscle and joint proprioceptors
- Trigeminal nuclei
What may be the greatest cause of headaches and dizziness?
Cervicogenic pain
Cervicogenic vertigo
T/F Movements that are mainly unilateral receive primary innervation from the contralateral hemisphere
True
Cranial nerves I and II are not true nerves, but instead are ____________
Fiber tracts of the brain
T/F Except for part of C.N. XII, the caudal 10 pairs of cranial nerves emerge from the brain stem in which lies their nuclei of origin
FALSE.
All except I, II, and part of XI
The area of the brain where the nerve appears or attaches
Superficial origin
C.N. that have motor function take their nuclei of origin from a collection of cells deep within the brain stem (motor nuclei) which are analogous to what part of the spinal cord?
Anterior horn cells
Sensory C.N. originate from a collection of cells outside the brain stem, usually in ganglia that may be considered analogous to the _______________ of spinal nerves
Dorsal root ganglion
Several reasons that may cause cranial nerve abnormalities
1) Specific lesion to the nerve
2) Lesion in the nucleus
3) Lesion in the communicating pathways to and from the cortex, diencephalon, cerebellum, or other parts of the brain stem
4) Generalized problem of nerve of muscle
What would allow a lesion to affect multiple nerves?
1) Lesion is where several C.N together in the brain stem or in the skull
2) When they are affected by a generalized disorder
3) Following multiple lesions
Cerebellopontine angle lesion would cause abnormalities in what nerves?
V, VII, VIII
Cavernous sinus lesion would cause abnormalities in what nerves?
III, IV, V, VI
Jugular foramen syndrome lesion would cause abnormalities in what nerves?
IX, X, XI
In Cerebellopontine angle lesions, Cavernous sinus lesions, and Jugular foramen syndrome lesions, would it affect the nerves bilaterally or unilaterally?
All conditions would cause unilateral abnormalities to their respected nerves
What condition would cause abnormalities in C.N. X, XI, and XII if it affected a lower motor neuron?
Bulbar palsy
What condition would cause abnormalities in C.N. X, XI, and XII if it affected a upper motor neuron?
Psuedobulbar palsy
The sensory nuclei develop within the dorsal or__________ of the neuro tube, the motor nuclei develop within the ______________
Alar plate
Basal plate
Name and location of C.N. III motor nucleus
Edinger-Westphal nucleus
Level of Superior colliculus
Name and location of C.N. IV motor nucleus
Nucleus of Trochlear nerve
in midbrain at level of the inferior colliculus
Name and location of C.N. V motor nucleus
Motor nucleus of the Trigeminal nerve
at level of mid Pons
Name and location of C.N. VI motor nucleus
Nucleus of Abducens Nerve
in dorsal Pons
Name and location of C.N. VII motor nucleus
Nucleus of the Facial Nerve
near caudal border of the Pons
Name and location of C.N. VII and IX motor nuclei
VII = Nucleus Salivatorius superior
IX = Nucleus Salivatorius inferior
both are at border of Pons and Medulla
Name and location of C.N. X motor nucleus
Dorsal motor nucleus of the Vagus nerve
in dorsal medulla
Name and location of C.N. IX, X, and XI motor nuclei
Nucleus ambiguous (IX, X, and XI) in dorsal medulla
Name and location of C.N. XII motor nucleus
Nucleus of Hypoglossal nerve
in medulla beneath 4th ventricle
Name and location for the sensory nuclei of C.N. V
V= Trigeminal nerve
Mesencephalic nucleus of Trigmeinal (mid brain)
Main sensory nucleus of Trigeminal (pons)
Nucleus of Spinal tract of Trigeminal (dorsal lateral medulla)
Name and location of C.N VIII sensory nuclei
VIII = Vestibulocochlear
Vestibular and cochlear nuclei of acoustic nerve (pons and medulla)
Name and location of C.N. VII and IX sensory nuclei
Nucleus of Tractus Solitarius
dorsal medulla
How to assess C.N. I
- Observation of external nose
- Observation of the internal nasal passage
- Check sense of smell by testing each side separately and with a different scent
How to assess C.N. II
- Observation of the eyes (limbus to lid, limbus to canthi)
- Test visual acuity (near and far)
- Test gross visual field (peripheral vision a.k.a. Confrontation)
- Pupillary light reflex (II or III)
- Ophthalmoscopic exam
How to assess C.N. III, IV, and VI
- Observation of the eyes (limbus to lid, limbus to canthi)
- Corneal light reflex
- Pupillary light reflex
- Cardinal fields of gaze
How to assess C.N. V
- Corneal blink reflex
- Light touch sensation on the face
- Sharp sensation on the face
- Inspect muscles of mastication for tine and strength
- Jaw jerk reflex
- General sensation of the anterior 2/3 of the tongue
How to assess C.N. VII
- Check musculature of the face (smile, look up, etc.)
- Check taste (anterior 2/3 of the tongue)
How to assess C.N. VIII
- Observation of the external ears
- Observation of the internal ears
- Rinne test
- Weber test
- Finger rustle test
- Schwabach test
- Watch tick test
How to assess C.N. IX and X
- Have the patient say “Ahhhhhhh” (soft palate should rise
- Gag reflex (posterior 1/3 of the tongue)
- Check phonation (K-L-M test. pronounce the sounds kuh la mi)
How to assess C.N. XI
- Shoulder elevation
- Muscle strength (SCM and Trapezius)
How to assess C.N. XII
- Stick out tongue
- Tongue in check
