Brainstem Flashcards
What separates the two cerebral peduncles
interpeduncular fossa
3 Axons in the cerebral peduncle
corticopontine, corticospinal, and corticobulbar
Where do oculomotor (III) Emerge in the brainstem
From the midbrain between the peduncles in interpeduncular fossa
Which Cranial Nerves exit medially?
Which Cranial Nerves exit laterally?
Motor neurons exit medially (III< IV, VI, XII)
Mixed Nerves exit laterally (V,VII,VIII, IX,X)
Where do the CN5 fibers enter or exit
rostral pons
Where do fibers of CN6,7,8 enter or exit
At the pontomedullary junction
Where do the roots of CN9 and 10 enter or exit
Dorsolateral to the olive
Where does cranial nerve 12 exit
Medial to olive and lateral to the pyramid
Cranial nerve 4 is the only (2 things)
Only dorsally exiting and only fully crossed nerve
What courses with the corticospinal tract and what does it synapse with?
Corticobulbar travels with corticospinal and innervates lower motor neurons in cranial nerve nuclei
Track in anterolateral system that synapses in the pons?
Spinoreticuar Tract
Tract running in anterolateral system that branches off in the midbrain?
SPinomesencephalic Tract
Patients with Central Horner’s syndrome may also have?
loss of pain and temp contralateral
MLF links which nuclei
8 with 6,4,3
MLF is especially succeptible to
CNS diseases like MS and neurosyphilis
- intranuclear ophthalmoplegia that dirupts horizontal conjugate gaze and vestibulo-ocular reflex
4 things found in every brainste section
Unique fact about corticoblbar innervation of hypoglossal nucleus and ambiguus nucleus
both nuclie may have more of a contralateral innervation tha t predominates over an ipsilateral corticobulbar innervation
In lesion of corticobulbar to hypoglossal nucleus what signs do you see
tongue muscle does not undergo fasciculations or atrophy. Deviate away from lesioned side.
Lesion of corticobulbar to nucleus ambigusus resuts?
uvula may deviate towards the lesioned fibers. Normally away in vagus nerve lesion
Unique factor of innervation of CN7
only eyes and forehead bilaterally innervated. So UMN lesion only affects lower contralateral face.
Brainstem CS tract lesion symptoms?
Medial Lemniscus ?
Spinothalamic
Descending hypothalamic
- which CN deficits will yous see
What divides motor and sensory in the spinal cord and brainstem
Motor nuclei general organization
Skeletal Muscle, glands/smooth ucle/cardiac muscle, skeletal muscle of pharyngeal arches
Sensory ncueli general organization in brainstem
touc/pain/prop
stretch, chemo, baro
taste and olfactory
retina, auditory, vestibular
Bell’s palsy
Lesion 7 skeletal muscles. paralysis of facial muscles ipsiltaeral. Hyperacusis, hypersensitiveity,
When to think around the brainstem
Consider the brainstem when?
What is the 4-4-4 rule of the brainstem
What is important about Corticospinal tract in determining brainstem lesions
3 Steps in ventral to dorsal localization
Medial to Lateral Localization
2 Features
Vascular supply to the brainstem
What supplies the medial
hat supplies hte ventral lateral
what supplies the dorsal lateral
Internuclear Ophthalmoplegia (INO)
What is it?
What causes it?
Internuclear Ophthalmoplegia cause in old and young
Impaired Corneal Reflex Tests
What does result show
Tests CN 5 and 7
If other eye cloess than corneal reflex is simpaired secondary to facial weakness (CN7)
If the other eye does not close, then the corneal reflex is impaired secondary to facial numbness CN5
If both affected than neither eye would close when ouchign lesioned side.
Common cause of Central Horner’s Syndrome
Common cause of second order Horner’s Syndrome
Common cause of third-order neuron lesion
Fifth Nerve Palsy
Jaw deviates to the weak side
9th and 10th nerve palsy observation
palate deviates away from lesion because of unopposed action of normal levator veli palatini
12th nerve palsy
Tongue atrophy on same side of lesion. Tongue deviates tto the same side as the lesion
