Cranial Nerves Flashcards
Name, CNS origin, and distribution CN I
Olfactory
Telencephalon
Olfactory mucosa of nose
Name, CNS origin, and distribution CN II
Optic
Diencephalon
Retina of eye
Name, CNS origin, and distribution CN III
Oculomotor
Midbrain/Mesencephalon
Intraocular and 4 extra-ocular muscles
Name, CNS origin, and distribution CN IV
Trochlear
Midbrain
Superior Oblique extra-ocular M.
Name, CNS origin, and distribution CN V
Trigeminal
Pons/Metencephalon
Derivatives of 1st pharyngeal arch
Name, CNS origin, and distribution CN VI
Abducent/Abducens
Pontine Medullary Jxn
Lateral Rectus M. of the eye
Name, CNS origin, and distribution CN VII
Facial
Pontine Medullary Jxn
Derivatives of 2nd Pharyngeal Arch
Name, CNS origin, and distribution CN VIII
Vestibulocochlear
Pontine Medullary Jxn
Internal ear
Name, CNS origin, and distribution CN IX
Glossopharyngeal
Medulla/Myelencephalon
Derivatives of 3rd pharyngeal arch
Name, CNS origin, and distribution CN X
Vagus
Medulla/Myelencephalon
Derivatives of the 4th pharyngeal arch
Name, CNS origin, and distribution CN XI
Spinal Accessory
Superior Spinal Cord
Superficial layer of neck
Name, CNS origin, and distribution CN XII
Hypoglossal
Medulla/Myelencephalon
Muscles of tongue
What CNs do the general somatic efferent fibers travel within? What do they innervate?
CN 3, 4, 6, 12
Somatic muscle
What CNs do the general visceral effernt fibers travel within?
Parasympathetic of CN 3, 7, 9, 10
Autonomics to smooth and cardiac muscle and glands
What CNs do the fibers of the branchial or special visceral efferents travel in?
CN 5, 7, 9, 10
Muscles derived from teh pharyngeal arches
What do the general somatic afferrent fibers innervate? From what embryological layer?
Sensation to skin, joint capsule, tendon, muscle
Ectoderm/Ectoderm-adjacent mesoderm
What do the general visceral afferent nerve fibers innervate? From what embryological layer?
Sensory of visceral structures (organs)
Endoderm/Endoderm-adjacent mesoderm
What CNs do the special somatic afferent fibers run with? What do they control?
CN 8 - hearing
Balance
CN 2 - Sight
What CNs do the special visceral afferents run with? What do they control?
CN 7, 9 10 - taste
CN 1 - Smell
Where is CN1 located? Where does it synapse onto?
Olfactory organ through cribiform plate to synapse onto Olfactory bulb
What is Halo sign?
Blood separation from nasal drainage which suggests CSF rhinorrhea/disruption of meninges
Compression of the optic chiasm by a pituitary tumor or an aneurysm in the internal carotid A. can result in what?
Bitemporal hemianopsia (lateral vision loss)
What visual acuity tests are done after a head injury?
Light and dark
Finger counting
What are the graded tests of visual acuity?
Light and dark
Finger counting
Snellen’s test
Visual field test
Peripheral vision
What are the afferent and efferent nerves involved in the pupillary light reflex?
Afferent - CN2/Optic
Efferent - CN3/Oculomotor
What are the afferent and efferent nerves involved in the blink reflex (when object is coming at eye)?
Afferent - CN2/Optic
Efferent: CN7/Facial N.
What is the general tract of CNII from the brain?
- Optic nerve fibers arise from ganglion cells in retina
- Exit orbit via optic canal into middle cranial fossa
- Synapse onto lateral geniculate bodies of thalamus
What is the general tract of CNIII from the brain?
- Exits midbrain through dura lateral to diaphragma sellae
- Runs in lateral wall of cavernous sinus
- Enters through superior orbital fissure into orbit