Brainstem/Cerebellum Flashcards
- Locate the hypoglossal nucleus and the hypoglossal nerve exiting the brainstem
- Point out the reticular formation
What is the reticular formation?
Diffuse nerve network throughout the entire brainstem that connects all the surrounding structures
What are the cranial nerves in the medulla?
CN IX, X, XI, and XII (9-12)
Name the labeled structures
What CN(s) come out the dorsal surface of the brainstem?
Only CN IV (trochlear)
What functional fibers are in CN XI?
-what does CN XI innervate?
GSE
- for this course consider CN XI (accessory) to contain GSE (as if it’s innervating muscles from somite, not branchial arch, derivatives)
- CN XI innervates trapezius and SCn
Point out the pyramidal decussation and medullary pyramids
Point out the place where the dorsal medial pathway fibers decussate and travel
Where does the hypoglossal nerve exit the brain?
Exits most medially out of the medulla. Exits out on the preolivary sulcus between the olive and the pyramids
How does the hypoglossal nerve leave the skull?
Out the hypoglossal foramen to provide motor innervation (GSE) to the tongue
Locate the spinal accessory nucleus in the image
Which number if the hypoglossal nuclei?
11
- most medial (b/c motor) in the medulla oblongata
- contains GSE fibers
Which number is the accessory nucleus?
20
-very medial (second most medial) in the superior spinal cord, GSE fibers
Point out the
(a) Nucleus that provides the SVE fibers to the vagus nerve
(b) Exit of CN X
(a) Nucleus ambiguus provides the parasympathetics to the vagus nerve
(b) CN X exits out the inferior olivary sulcus (right below the inferior olive)
Locate the nucleus that provides parasympathetics to the vagus nerve
= Dorsal motor nucleus of the vagus
Differentiate the location of the 4 pathways/nuclei that provide fibers to the vagus nerve
- yellow = nucleus ambiguus, provides the SVE fibers to muscles derived from the VI and VIth branchial arch
- darker blue = dorsal vagal motor nucleus, provides the GVE (parasympathetic) fibers for motor to the gut
- teal (most lateral) = spinal trigeminal nucleus (GSA fibers)
- purple/green = solitary nucleus (GVA and SVA)
Label the blue arrows and red line
- red line = sulca limitans, separates the motor and sensory components of the brainstem
- see CN IX exiting
- inferior salivatory nucleus provides the parasympathetics (GVE) to CN IX
- spinal trigeminal nucleus provides the somatic sensory (GSA) to both CN X and IX
- nucleus solitarious provides the visceral sensory (GVA) to both CN X and IX
- nucleus ambiguus provides the somatic sensory (GSA) to both CN X and IX
What is the main structure of the posterior fossa?
Cerebellum, takes up mostly all the psace in the posterior fossa => if anything takes up space it can cause herniation
What structure forms the roof of the 4th ventricle
Cerebellum
-then the lateral walls of the 4th ventricles are the peduncles running and out of the cerebellum
Which cerebral peduncle(s) are the main outflow tract of the cerebellum?
Superior cerebellar peduncles = main outflow tract for efferent fibers leaving the cerebellum
Which cerebral peduncle(s) are the main inflow tract of the cerebellum?
Middle and inferior cerebellar peduncles act as the inflow tracts for the afferent fibers going into the cerebellum
What is the clinical significance of the cerebellar tonsils?
Tonsils = lowest (most inferior/caudal) part of the cerebellum
=> any mass-consuming lesion in the posterior fossa (ex: hemorrhage, tumor, increased pressure) can cause herniation of the cerebellar tonsils thru the foramen magnum
Define a brainstem nucleus
Nucleus = gray matter- collection of neurons in a specific anatomical space
Which part of the cerebllum controls distal limb coordination?
Intermediate hemisphere
