Neuroanatomy - Cranial Nerves Flashcards
where do the cranial nerves exit the brainstem and which two are the exceptions?
anterior surface
IV/trochlear = posterior VIII/vestibulocochlear = lateral
what modality is contained in CN I?
purely sensory
what is the name of CN I?
olfactory nerve
what cranial nerve contains the only sensory modality that does not synapse in the thalamus prior to reaching the cortex?
CN I
what are the five motor cranial nerves?
III IV VI XI XII
where are the nuclei for the origin of the five motor cranial nerves located?
near the midline on the ventral aspect of the brain
what is the name of CN III?
oculomtor
what modalities does CN III contain?
somatic motor
parasympathetic
where do the parasympathetic neurones of CN III come from?
edinger westphal nucleus
what do the parasympathetic neurones of CN III supply?
sphincter pupillae
ciliary muscle
where do the motor neurons of CN III come from?
the oculomotor nucleus
what do the motor neurons of CN III supply?
levator palpebrae superioris
superior, medial and inferior rectus
inferior oblique
when do the two fibre types in CN III come together to form the nerve?
as they pass through the basis pedunculi
what is the name of CN IV?
trochlear nerve
what modality does CN IV contain?
somatic motor
what does CN IV supply?
superior oblique muscle
where is the nucleus of CN IV located?
at the level of the inferior colliculus
called the trochlear nucleus
where does CN IV originate?
the trochlear nucleus
what is the name of CN VI?
abducens nerve
what modality does CN VI contain?
somatic motor
where does CN VI originate?
abducens nucleus
where is the abducens nucleus located?
near the midline in the lower pons
where do the fibres of CN VI exit the brain?
in the ponto-medullary junction
what is the name of CN XII?
hypoglossal nerve
what modality does CN XII containn?
somatic motor
where does CN XII originate?
the hypoglossal nucleus
where is the hypoglossal nucleus located?
from the lower pons through most of the medulla, close to the midline
where does CN XII exit the brain?
anteriorly between the olive and the pyramid
what is the name of CN XI?
spinal accessory nerve
where does CN XI arise?
the cervical spinal cord
what are the four mixed cranial nerves?
V
VII
IX
X
what is CN V called?
trigeminal nerve
what are the three main functions of CN V?
somatosensation of face
proprioception associated with chewing
motor control
what muscles are innervated by CN V?
muscles of mastication tensor tympani mylohyoid anterior belly of digastric tensor veli palatini
what are the three sensory nuclei of CN V?
mesencephalic nucleus
pontine trigeminal nucleus
spinal nucleus
what is the role of the mesencephalic nucleus of CN V?
information regarding proprioception from the teeth and jaw arrive here
what is the principal sensory nucleus of CN V?
pontine trigeminal nucleus
what information is associated with the pontine trigeminal nucleus of CN V?
discriminative touch
vibration
what information is associated with the spinal nucleus of CN V?
pain
temperature
where is the sensory nucleus of CN V found?
a long column from the midbrain to the upper two segments of the cervical spinal cord
three parts separated by function
what is the name of CN VII?
facial nerve
what three modalities are found in CN VII?
motor
parasympathetic
special sensory - taste
where do the motor fibres of CN VII innervate?
muscles of facial expression
stapedius
where do the parasympathetic fibres of CN VII innervate?
pterygopalatine ganglia
submandibular ganglia
where does CN VII supply the special sense of taste and how?
anterior 2/3 of the tongue
via the chorda tympani
what are the four nuclei of CN VII?
facial motor nucleus
salivatory nucleus
solitary nucleus
spinal trigeminal nucleus
what does the facial motor nucleus of CN VII supply?
muscles of facial expression
what does the salivatory nucleus of CN VII supply?
parasympathetics
what does the solitary nucleus of CN VII supply?
special sensory - taste
what does the spinal trigeminal nucleus of CN VII supply?
somatosensation in a small region around the ear
what are the four nuclei of CN IX?
solitary nucleus
spinal trigeminal nucleus
inferior salivatory nucleus
nucleus ambiguus
what is CN IX called?
glossopharyngeal nerve
what are the two parts of the solitary nucleus of CN IX and what do they supply?
gustatory = muscles and taste
commissural = visceral information
what does the spinal trigeminal nucleus of CN IX supply?
somatosensation to a small region associated with teh ear
what does the inferior salivatory nucleus of CN IX supply?
parasympathetics
what does the nucleus ambiguus of CN IX supply?
motor to stylopharyngeus
what is the name of CN X?
vagus nerve
what are the four nuclei associated with CN X?
dorsal nucleus
solitary nucleus
spinal trigeminal nucleus
nucleus ambiguus
what does the dorsal nucleus of CN X supply?
parasympathetics
what does the solitary nucleus of CN X supply?
gustatory part - taste
commissural part - visceral information
what does the spinal trigeminal nucleus of CN X supply?
pain from dura
small region of somatosensation associated with the ear
what does the nucleus ambiguus of CN X supply?
motor to pharynx and larynx
what part of the corticospinal tract provides motor input to cranial nerve nuclei?
the corticobulbar tract
which motor nuclei receive input from the corticobulbar tract?
V
VII
X
XII
what cranial nerves innervate the extraocular muscles?
III
IV
VI
where does motor input to the CN’s innervating extraocular muscles come from?
complex interplay of inputs from the:
- frontal lobes
- parietal lobes
- reticular formation
- visual cortex
- vestibular system
what cranial nerves contain parasympathetic efferents?
III
VII
IX
X
where does motor input to cranial nerves containing parasympathetic efferents come from?
hypothalamus
what is the reticular formation?
a network of loosely aggregated cells with cell bodies, axons and dendrites intermingling in the central core of the brainstem
