Psarros Chapter 2 Flashcards
This connects the medial, intermediate, and lateral olfactory areas
diagonal band of Broca
Which thalamic nuclei facilitates the conscious perception of smell
projections from the pyriform cortex to the mediodorsal nucleus of the thalamus which then projects to the orbitofrontal cortex
Through what path do the olfactory areas project to the hypothalamus?
medial forebrain bundle
Through what pathway do the olfactory areas project to the habenular nuclei
stria medullaris thalami
Through what pathways does the amygdaloid body transmit to the anterior hypothalamus?
stria terminalis
what pathways facilitate visceral responses to olfactory stimuli?
through hypothalamic and habenular nuclei projections to the reticular formation
optic tracts project to the lateral geniculate bodies of the thalamus except for a small number of fibers that project to what area for the pupillary light reflex
pretectal nuclei
the upper bank of the visual cortex is comprised of this gyrus
cuneus
the lower bank of the visual cortex is comprised of this gyrus
lingual
the primary visual cortex projects to this
secondary visual cortex (areas 18 and 19)
why is there macular sparing with PCA infarcts
the occipital poles are also supplied by the MCA
what nucleus provides preganglionic parasympathetic fibers to CNIII
Edinger-Westphal
what is the route of the CNIII fibers?
the lower motor neurons pass through the red nuclei and the medial portion of the cerebral peduncles before exiting. CNIII passes between the PCA and the SCA before entering the cavernous sinus. It hugs the lateral border of the cavernous sinus and enters the superior orbital fissure, then through the annulus of zinn before dividing into superior and inferior divisions
which portion of CNIII do the parasympathetic fibers exit
they exit the inferior division of CNIII to synapse in the ciliary ganglion. Postganglionic fibers innervate the constrictor pupillae and the ciliary muscles.
What are the signs and symptoms of a lower CNIII lesion
ipsilateral ptosis, pupillary dilation, accomodation paresis, diplopia, and downward, abducted eye deviation.
where is the trochlear nucleus?
at the level of the inferior colliculus in the mesencephalon
Which cranial nerve exits the brainstem dorsally
CNIV
What path does CNIV take?
exits the brainstem dorsally and decussates through the superior medullary velum (roof), then courses lateral to the cerebral peduncles and passes between the posterior cerebral and superior cerebellar arteries lateral to CNIII. It eventually pierces the tentorium cerebelli before entering the lateral wall of the cavernous sinus. It passes above the annulus of Zinn through the superior orbital fissure
What nerve decussates outside of the CNS?
CNIV
What results from CNIV lesion?
extorsion of the ipsilateral eye with diplopia on downward gaze. As a result, patients tilt their head contralaterally to compensate (Bielschowsky’s sign)
What CN is a/w the first branchial arch?
Trigeminal
what composes the trigeminal nerve
portio major (sensory) and portio minor (motor)
where is the trigeminal ganglion?
meckels cave
pathway of the trigeminal nerve?
V1: superior orbital fissure
V2: foramen rotundum
V3: foramen ovale
V1/2 travel through the cavernous sinus. The motor portion travels along V3
Major branches of the trigeminal nerve?
V1: lacrimal, frontal, and nasociliary (passes through annulus of zinn)
V2: zygomatic, infraorbital, pterygopalatine, meningeal
V3: buccal, auriculotemporal, lingual, inferior alveolar, and meningeal
Special sensation of trigeminal nerve?
Anterior two thirds of taste and external surface of the tympanic membrane through V3
what portions of the dura are innervated by CNV?
anterior and middle fossa
What does the SVE component of CN5 innervate?
muscles of mastication (first branchial arch): tensor veli palatini, tensor tympani, masseter, pterygoids, temporalis, mylohyoid, anterior body of the digastric
nuclei of the trigeminal nerve
- motor
- sensory
- mesencephalic: proprioception from mastication muscles
- nucleus of the spinal tract: pain and temperature sensation from the face (from pons to the cervical spinal cord)