Exam 3 Part 2 - Clinical Scenarios and Notes Flashcards
1
Q
Divisions of the Brainstem (3)
A
Mesencephalon: tectum, cerebral aqueduct, crura cerebri
Metencephalon: cerebellum, 4th ventricle , pons
Myencephalon: PCs, central canal, pyramids
all of these contain the tegmentum
2
Q
In cross sections of the brainstem, how do the penetrating arteries appear?
A
Wedge-shaped pattern of distribution - a thrombosis here is a reason we get lesion patterns
3
Q
Seven major ascending and descending pathways:
A
Spinal Lem, Medial Lem, Lateral Lem, Trigeminal Lem, Descending Tract of V, MLF, CST, and CBT
4
Q
Spinal Leminiscus is responsible for:
A
Contralateral pain and temperature of the BODY
5
Q
Medial Lemniscus is responsible for:
A
Contralateral propioception of the BODY
At the level of upper pons/midbrain: conveys taste from ipsilateral tongue
6
Q
Trigeminal Lemniscus is responsible for:
A
Contralateral pain, temperature, and crude tactile of the FACE
7
Q
Lateral Lemniscus is responsible for:
A
Bilateral auditory information but primarily the opposite ear
8
Q
Medial Longitudinal Fasciculus conveys:
A
Vestibular influences to the CN 3, 4, 6
involved in multiple sclerosis
9
Q
General Lesions of the MLF results in:
A
Internuclear Ophthalmoplegia = abnormal response to horizontal gaze in the direction OPPOSITE to the lesion
10
Q
Unilateral Lesion of the MLF results in:
A
Impairment/loss of adduction (medial rectus) of the ipsilateral eye, and nystagmus of the abducting eye
11
Q
Corticospinal Tract is responsible for:
A
Conveys descending motor information from the motor cortex
12
Q
Parts of the Corticospinal Tract
A
Midbrain: middle 3/5 of the cerebral peduncle
Pons: fascicles by the pontine nuclei
Medulla: forms the pyramids and fibers will decussate in the lower medulla
13
Q
Unilateral lesion of the corticospinal tract is called:
A
Contralateral Spastic Hemiplegia
14
Q
Brainstem cranial nerve motor nuclei are innervated by what types of fibers?
A
Corticobulbar Tract Fibers
15
Q
Unilateral Lesion of the CBT
A
Denervation of the motor nuclei below the level of the lesion (some motor nuclei like the facial one receive input from both hemispheres so they won’t be affected)
16
Q
Unilateral lesions of the CBT above the level of the decussation?
A
Results in contralateral paralysis or paresis of the mimetic muscles (supranuclear facial palsy) as well as other palsies from CN 6, 12, 10
17
Q
Unilateral lesions of the CBT below the decussation?
A
Ipsilateral cranial nerve palsies
18
Q
80% of strokes appear where?
A
In the internal capsule or the basal ganglia
19
Q
Cranial Nerves of the Diencephalon
A
CN 2 - leads to visual field blindness
20
Q
Cranial Nerves of the Midbrain
A
CN 3 and 4
21
Q
Cranial Nerves of the Pons
A
CN 5 - ipsilateral loss of sensations from face
22
Q
Cranial Nerves of the Pontomedullary Sulcus
A
CN 6, 7, and 8
23
Q
Cranial Nerves of the Medulla Oblongata
A
CN 9-12
24
Q
Lesion of the Nucleus Ambiguus
A
Deviation of the uvula away from the affected nucleus
25
Lesion of the Hypoglossal Nucleus
Protruded tongue towards the side of the affected nucleus
26
How do you determine how large the lesion is?
By the number and location of the central pathways involved.
27
How do you determine the level and side of the lesion?
This depends on the symptoms from the HIGHEST cranial nerve and which side it correlates to
28
Lesion to the Descending Tract of V
Loss of pain/temp sensations from the same side of the FACE
29
Alternating Hypoglossal Hemiplegia
Shorthand: A12H
Symptoms: tongue protrudes to ipsilateral side (hypoglossal nucleus) and contralateral spastic hemiplegia
30
Important Similarities b/t the Alternating Hemiplegias
Each of them exit the brainstem adjacent to the CST so when they are cut, the IPSILATERAL CST is too = contralateral spastic hemiplegia
31
Alternating Hypoglossal Hemiplegia + Destruction of Contralateral CST
Shorthand: A12H + CST
Symptoms: tongue protrustion, contralateral spastic hemiplegia, and the second CST will result in the ipsilateral spastic paralysis
32
Alternating Hypoglossal Hemiplegia + Ipsilateral ML
Shorthand: A12H + ML
Symptoms: tongue protrustion, contralateral spastic hemiplegia, and contralateral loss of propioception
33
Alternating Abducent Hemiplegia
Shorthand: A6H
Symptoms: ipsilateral paralysis of lateral gaze, internal strabismus and contralateral spastic hemiplegia
34
Millard-Gubler's Syndrome
Shorthand: A6H + 7
Symptoms: ipsilateral paralysis of lateral gaze, internal strabismus and contralateral spastic hemiplegia AND ipsilateral facial palsy, loss of taste, decreased lacrimation, hyperacusis
35
Syndrome of Foville
Shorthand: A6H + ML + MLF
Symptoms: ipsilateral paralysis of lateral gaze, internal strabismus and contralateral spastic hemiplegia AND contralateral loss of propioception, AND internuclear ophthalmoplegia
**destruction of the CROSSEDCBT --> nucleus ambiguus, hypoglossal nerves**
36
Alternating Trigeminal Hemiplegia
Shorthand: A5H
Symptoms: ipsilateral loss of face sensations, paralysis of muscles of mastication, and contralateral spastic paralysis
37
Alternating Trigeminal Hemiplegia with Dorsal Expansion
Shorthand: A5H + ML
Symptoms: ipsilateral loss of face sensations, paralysis of muscles of mastication, and contralateral spastic paralysis AND contralateral loss of propioception from body
**destruction of UNCROSSED CBT --> abducens, facial, hypoglossal, and nucleus ambiguus**
38
Alternating Oculomotor Hemiplegia (Weber's Syndrome)
Shorthand: A3H
Symptoms: external strabismus, pupillary dilation, and complete ptosis; contralateral spastic hemiplegia
**destruction of the substantia nigra may cause contralateral resting tumor, UNCROSSED CBT may cause supranuclear facial palsy**
39
Where do the CBT fibers decussate?
In the lower pons between the levels of the trigeminal and abducens nerve.
40
What specific characteristic can you look for to know the disease includes uncrossed CBT fibers?
Look for supranuclear facial palsy!
41
Lesion of the Nucleus Ambiguus and Spinal Lemniscus
NA Symptoms: dysphagia, dysarthria, hoarseness
SL Symptoms: contralateral loss of pain and temperature from the body
**may also include the ML and solitary nucleus**
42
Lateral Medullary Syndrome (Wallenberg's or Syndrome of PICA)
Shorthand: SL + Desc Tract of V + CN 9,10
Destruction of the SL (contra loss of pain/temp from body) and descending tract of V (ipsilateral loss of pain/temp from face)
**key symptoms: Alternating Hemianalgesia + Dysphagia**
43
Cerebellopontine Angle (CPA) Syndrome
Shorthand: SL + Desc Tract V + CN8
Destruction of CN8 results in deafness and vestibular disturbances
**Key symptoms: Alternating Hemianalgesia + Deafness**
44
Benedikt's Syndrome (Lesion in Midbrain Tegmentum)
Shorthand: CN3 + ML
Destruction of CN 3 (external strabismus, pupil dilation, ptosis) and ML (contralateral loss of propioception from body)
Lesion of the red nucleus: may have tremor, ataxia
45
Parinaud's Syndrome
Due to a lesion of the superior colliculus which controls upward gaze (they won't be able to look straight up)
May be due to a pineal tumor, lesions may destroy the posterior commissure (no consensual light reflexes)
46
Unilateral Lesions of VPM and VPL
Contralateral Hemianesthesia:
- loss of pain/temp on contralateral face and body
- loss of propioception from contralateral body and ipsilateral head
47
Thalamic Syndrome (Dejerine-Roussy Syndrome)
Due to thrombosis of the branches of PCA
Symptoms: spontaneous pain, extreme mood swings, may also involve contralateral hemihypalgesia (crawling ants feeling)
48
Relationships of the Vestibular Nerve
Enters brainstem at pontomedullary sulcus
| Travels beneath the restiform body
49
Primary neuron of the vestibular nerves bifurcate and terminate in these locations: (3)
Vestibular nuclei
Fastigial nuclei
Flocculo-nodular lobe
50
MLF in the Vestibular Nuclei
Terminates in the CN3, 4, and 6 nuclei, responsible for synchronized eye movements
51
Vestibulo-ocular responses can be tested clinically by:
Doll's Head Maneuver or Oculocaloric (ice water) testing
52
Paramedics Pontine Reticular Formation (PPRF)
Critical center for horizontal gaze - affects the abducens nerve/lateral rectus muscle so that the ipsilateral affected eye CANNOT look outwards (right eye cannot abduct)
53
Medial Vestibulospinal Trac
**responsible for movements of the head**
Influences the muscles of the neck, upper neck, and proximal upper limbs - moves the head relative to eye movements
54
Lateral Vestibulospinal Tract
**moves the rest of the body**
Facilitates the extensor tone and reflexes of the antigravity axial and appendicular musculature
55
Vestibulospinal-cerebellum refers to these structures:
The flocculo-nodular lobe, underlying deep cerebellar nuclei, and the fastigii
56
Normal Results for the Doll's Eye Maneuver
Normally (without cervical injury) we would expect the eyes to move in the opposite direction of the head
57
Oculocaloric Testing for Vestibulo-ocular Response
In an UNCONSCIOUS patient, injection of cold water into the external auditory meatus results in horizontal gaze toward the side of the stimulus
Example: If water is poured into right ear
- Right eye abducts, left eye adducts = normal finding
- Right eye abducts = left III nerve palsy
- Left eye adducts = Right VI palsy
- No responses = Right VIII palsy, midbrain damage
58
Unilateral Lesions of the Vestibular Systems
Postural impairment
Eyes, head, body turn towards affected side
Patients tends to fall towards that side
Nystagmus and vertigo
59
Internuclear Ophthalmoplegia (INO)
Named according to the side of the oculomotor impairment:
- is horizontal gaze to the right is normal, and dis conjugate to the left (right eye doesn't adduct) = RIGHT INO
- if left eye doesn't adduct and right eye has nystagmus = LEFT INO
60
80% of the INO cases are either young adults with _____ or older patients with _____
Young: bilateral INO with MS
Old: unilateral INO with vascular disease
61
Central core of the white matter of the cerebellum is called _____ and includes _____
Corpus Medullares
Includes: fastigial nucleus, globuse nucleus, emboliform nucleus, and the dentate nucleus
62
Fastigial Nucleus
Medial-most nucleus of the four nuclei, has vestibular connections and function
63
Dentate Nucleus
Cup-shaped nucleus that gives rise to most of the efferents in the superior cerebellar peduncle (called the dentato-rural tract)
64
Vestibular efferents will come from what part of the cerebellum?
Inferior cerebellar peduncle
65
Cerebellar afferents that course through the inferior cerebellar peduncle: (mnemonic)
DDT Always Ruins Olives
1. DSCT
2. Direct Arcuate Fibers/Cuneocerebellar Tract
3. Trigeminocerebellar Tract
4. Arcuocerebellar Fibers
5. Reticulocerebellar Fibers
6. Olivocerebellar Fibers
66
Dorsal Spinocerebellar Tract is responsible for:
Unconscious, precise information from the lower 1/2 of the body
Spinal nerves terminate in the nucleus dorsalis (C8-L3)
67
Cuneocerebellar Tract is responsible for:
Unconscious, precise information from the upper 1/2 of the body
These fibers terminate in the vermis
68
Trigeminocerebellar Tract is responsible for:
Unconscious sensory tracts from the face (general propioception)
Moderate number of fibers from subnuclei Rostralis and Interpolaris to the anterior vermis
69
Olivocerebellar Fibers
Heavily influence the purkinje cells of the cerebellar cortex
These fibers originate in the ION and terminate as climbing fibers in the contralateral cerebellar hemisphere
70
The ION receives direct input from:
Central tegmental fasciculus and the spinoolivary tract
71
Central Tegmental Fasciculus (CTF)
- originates in the red nucleus
| - this tract is a critical link between the extra pyramidal system and cerebellum
72
What fibers make up the middle cerebellar peduncle?
Pontocerebellar fibers
73
Ventral Spinocerebellar Tract is responsible for:
Unconscious, general propioception from the lumbosacral levels to the cerebellum
74
All information entering the cerebellar cortex eventually converges upon _____
The purkinje cells - these are the only efferents from the cerebellar cortex (and they are inhibitory)
75
Signs and Symptoms of Cerebellar Dysfunction
Results in ipsilateral deficits
Symptoms: dysmetria, ataxia, dysdiadochokinesia, intention tremor
76
Friedreich's Ataxia
**Just know this is a good cerebellar disorder with the typically expected symptoms**
77
Where are the CBT fibers located as compared to the the CST fibers?
CBT: genu of the internal capsule
CST: posterior limb of the internal capsule
78
Motor regions of the brainstem are usually located in what part?
Anterior (red areas shaded on photo in lecture)
79
Bell's Cruciate Paralysis
Characterized by midline involvement of the upper portion of the pyramidal decussation resulting in paralysis of the upper extremity (without lower extremity involvement)
**this can happen with damage to the odontoid process because it's adjacent to the pyramids**
80
What is the extrapyramidal system (EPS) responsible for?
Crude, associative movements of the axial and proximal limb musculature
**EPS initiates movements through the subcortical loops**
81
Parts of the Basal Ganglia
Globus pallidus (GP), caudate nucleus, putamen, substantia nigra, red nucleus
82
Motor nucleus of the thalamus refers to:
The ventral anterior and ventral lateral nuclei
83
Connections of the Globus Pallidus
Dorsal division of the ansa lenticularis = lenticular fasciculus
Ventral division of the ansa lenticularis
84
Connections of the Substantia Nigra
Nigro-thalamic fibers = pars reticularis --> terminate in the VA and VL thalamic nuclei
Nigro-striatal fibers = pars compacta --> terminates in the caudate and putamen (striatum)
85
Destruction of inhibitory GABAnergic fibers in the striatonigral fibers results in:
Huntington's Chorea
86
Fibers in the GP and SN don't terminate in the same place - this is important for what procedure?
Stereotaxic surgery for Parkinson's disease
87
Destruction of Nigrostriatal Fibers results in:
Parkinson's Disease
| Dopaminergic
88
Symptoms and Cause of Parkinson's Disease
Symptoms: Bradykinesia, tremors during rest, rigidity, reptilian gaze, glabellar reflex, postural embrassment, autonomic effects, cognitive changes
Caused by: degeneration of SN, GP, brainstem RF, and postganglionic sympathetic neurons
89
Symptoms and Cause of Huntington's Chorea
Symptoms: 30-40yrs onset, choreiform movements, severe dementia, choreoathetosis (involuntary movements), behavioral disturbances
Caused by: autosomal dominant (chromosome 4), degeneration of corpus striatum and cerebral cortex (destruction of the GABAnergic fibers)
90
Symptoms and Cause of Hemichorea
Symptoms: unilateral choreiform (repetitive, rapid) movements
Caused by: vascular lesion in the basal ganglia
91
Symptoms and Cause of Athetosis
Symptoms: slow, involuntary, writhing movements of the limbs and face
Caused by: degeneration of the striatum
92
Symptoms and Cause of Hemiballism
Symptoms: contralateral, violent flailing movements of proximal musculature (both upper/lower extremities)
Caused by: unilateral lesions of the subthalamus result in a reduction of glutamate inhibition on the globus pallidus
93
Spinal Cord Growth in a 3 Month Fetus
Spinal cord extends throughout the entire length of the vertebral column
94
Spinal Cord Growth in a 5 Month Fetus
Vertebral column is longer than the spinal cord; conus medullaris is at the level of SV1
95
Spinal Cord Growth in a Neonate
Conus medullaris is at the level of LV3
96
Spinal Cord Growth in an Adult
Conus medullaris is at the level of LV1-2 interspace
97
Rachischisis
Vertebral column defect, with exposure of primitive cord - NOT SURVIVABLE
98
Spina Bifida Occulta
Herniation of meninges or neural tissue - usually presents as a midline, hairy mass in lumbar region
May be caused due to failure of the roof plate of neural tube - may be asymptomatic for years
99
Meningocele
Vertebral column defect with herniation of meninges
100
Meningomyelocele
Vertebral column defect with herniation of meninges, spinal cord, or nerves
101
Anencephaly
Literally means "absence of the brain" but these babies still have a brainstem and vital functions
102
Meningoencephalocele
Cranial defect with herniation of meninges and brain tissue
Also all of these babies also have a chiari malformation and they may develop hydrocephalus
103
Meningohydroencephocele
Cranial defect with herniation of meninges, brain, and ventricles
104
Cranial Rachischisis
Congenital absence of the forebrain usually with cranial defect of frontal and parietal bones
**fatal anomaly**
105
Hydrocephalus
Congenital stenosis of a portion of the ventricular system or certain fetal infections
106
Arnold-Chiari Malformation
Common cerebellar anomaly that is almost always present with meningomyelocele, sometimes with syringomyelia
Involve elongation of the cerebellar vermis, which herniates through the foramen magnum
107
Three important structures of emotional expression:
Limbic lobe, neocortex, and hypothalamus that goes to the reticular formation
108
Scheme of the Reticular Formation
Ascending from the RF --> ARAS, centromedian nucleus hypothalamus, and special systems
Descending from the RF --> sensory and motor input
109
Importance of the Septal Areas
Near the corpus callosum, does addiction, pleasure/reward system, drugs
Receives input from olfactory system
110
Major feature of frontal lobe syndrome:
APATHY
111
Korsakoff's Syndrome
Bilateral destruction of the mammillary bodies and the dorsal medial nucleus of the thalamus
See an impairment in recent memory
Usually due to long-term chronic alcoholism, pituitary tumors
112
Papez Circuit
Responsible for flash/recent memory and shows the relationship between the cortex, amygdala, and septal areas
113
Papez Circuit in the Cortex
Mammillary body --> anterior tubercle --> cingulate gyrus --> entorhinal cortex --> hippocampus (receives all sensory)
Important tracts: fornix (sends info both ways), mammillothalamic between the MB and AT
114
Importance of Olfactory Input in Papez Circuit
Provides olfactory information to the hippocampus, amygdala, and the septal area
115
Communication between the Amygdala and Septal Areas
Amygdala --> Septal Area via the stria terminalis
| Amygdala --> Hippocampus via the ventral amygdalofugal fibers
116
Hypothalamus communicates with the septal areas and the midbrain tegmentum via:
Medial forebrain bundle
117
Primary Olfactory Cortex is made up of:
*Entorhinal Cortex* (which includes the uncus and rostral parahippocampus), lateral olfactory gyrus, amygdaloid nucleus
118
The amygdala is an important processing center for:
Olfactory, somatosensory, viscerosensory, and emotional expressions
119
Hippocampus is responsible for:
Memory storage and retrieval
120
Hippocampal Amnesia
Due to bilateral lesions of the hippocampi, sometimes happens after surgical resections for intractable epilepsy
Axons of neurons in this pathway send fibers to the entorhinal cortex (CA1 pyramidal cells)
121
Uncal Herniation Signs and Symptoms
Uncus usually herniates through the ipsilateral tentorial notch (can be due to a tumor or hematoma)
Compresses the follow: CN3 (external strabismus, ptosis), CN6 (gaze is down and in), Cerebral Peduncle (spastic hemiplegia ipsilateral), PCA (homonymous hemianopsia), ARAS, blood vessels, and hydrocephalus
122
In order to have language, what part of the brain is needed?
THE CORTEX
123
Layers 3-4 of the Cortex
Most of the afferents into the cortex
124
Layers 5-6 of the Cortex
Source of efferents from the cortex
125
Superior Longitudinal Fasciculus (SLF) or Arcuate Nucleus
Type of association fiber that is a critical link for language association areas
Lesions here: conduction aphasia (spontaneous speech, good comprehension, may have some right-sided paralysis)
126
Uncinate Fasciculus
Connects the association areas of the frontal lobe to the interior temporal lobe (this is connected to the entorhinal cortex)
127
Fibers of the Genu of IC
Corticobulbar (lesion = supranuclear facial palsy)
128
Fibers of the PLIC
Corticorubral
Corticospinal = contralateral spastic hemiplegia
Thalamocortical = contralateral hemianesthesia
129
Fibers of the Retrolenticular Portion of IC
Optic Radiations = contralateral homonymous hemianopsia
130
Nuclei of the Basal Ganglia
Substantia Nigra (pars compacta and reticularis)
Striatum (caudate and putamen)
Globus Pallidus
Subthalamic Nucleus
131
Nigrostriatal Dopaminergic System
SNPC --> nuclei of striatum
| Effects: Dopamine will either stimulate or inhibit
132
Intrastriatal Cholinergic System
Travels between nuclei of striatum
| Effects: excitatory (ACh)
133
Striatonigral GABAnergic System
"Direct Pathway"
Striatum --> SNPR and GPi --> thalamus
Effects: releases GABA, leads to initiation of movement
134
When the SNPC is abolished, what disease/effects does it have?
Parkinson's Disease
Direct pathway can't activate so the indirect pathway becomes overactive
Can't initiate motion
135
When the direct pathway is active...
ALLOWS MOTION
Needs Dopamine at D1, then GABA at VA/VL nuclei
136
When the indirect pathway is active...
INHIBITS MOTION
Needs lots of GABA to inhibit the thalamus
137
Voluntary motion comes from the association cortex and involves:
Planning of complex motor actions and carrying out the "thought" process
138
If the brain activates or inhibits an alpha motor neuron...
It will also activate or inhibit a gamma motor neuron
139
Reaching requires:
Dorsal pathway of the primary visual cortex
VIP cortex
F4
140
Grasping requires:
Inferior parietal cortex (anterior intraparietal area and PFG)
F5
141
Premotor Cortex receives input from...
F4 and F5, determines whether it is okay to move
142
Supplementary Motor Area (SMA)
Postural controls
143
Pre-SMA
Plans the motor program required to make the action occur
*also changes tactics if necessary*
144
Primary Motor Cortex
Codes motions to reach the goal
Arranged in columns that produce specific movements
Layer 4: sensory input
Layer 5: output for the CST
145
Role of the Cerebellum
Sequence complex actions
Correct forces/directions
Balance and eye movements
146
Spinocerebellum (vermis portion)
Postural controls
Inputs: vestibular, hearing, and auditory
Outputs: interpositus nucleus, fastigial nucleus (RST)
147
Spinocerebellum (lateral portion)
Feedback control of motion, ballistic motion
Inputs: efferent copy, afferents from muscle
Outputs: interpositus nucleus
148
Cerebrocerebellum
Planning complex motions, sequence rapid movement, learning
Inputs: cerebral cortex
Outputs: dentate nucleus
149
Vestibulocerebellum
Future balance and eye movements
Inputs: vestibular apparatus
Outputs: fastigial nucleus
