Neuro Mod 7 Flashcards
(108 cards)
1
Q
Anterior view midbrain landmarks?
A
Midbrain (cerebral peduncles), pons, medulla (pyramids and pyramidal decussation), cranial nerves 1-12
2
Q
Which cranial nerves (in anterior view) do not emerge from the brainstem?
A
1 & 2
3
Q
Which cranial nerves (in anterior view) emerge from the midbrain (brainstem)?
A
3 & 4
4
Q
Which cranial nerves (in anterior view) emerge from the pons (brainstem)?
A
5, 6, 7, 8
5
Q
Which cranial nerves (in anterior view) emerge from the medulla (brainstem)?
A
9, 10, 11, 12
6
Q
Medulla pyramids descend in the _______ _______ ______
A
corticospinal motor tract
7
Q
Medulla pyramidal decussation represent the descending portion of the corticospinal motor tract that ________ _______
A
Crosses midline
8
Q
A majority of medulla pyramidal decussation cross midline and descend in the spinal cord as _____ _____ ______
A
Lateral corticospinal tract
9
Q
Some medulla pyramidal decussation do not cross midline and descend in the spinal cord as ______ _______ ______
A
Anterior corticospinal tract
10
Q
Posterior view brainstem landmarks?
A
Superior colliculus, Inferior colliculus, CN4, 4th ventricle
11
Q
Which CN is the only one to emerge from the posterior brainstem?
A
CN4
12
Q
Sagittal view landmarks of the brainstem?
A
Midbrain, pons, medulla, superior colliculus, inferior colliculus, 4th ventricle, cerebral aqueduct
13
Q
What are the three horizontal regions of the brainstem?
A
Brainstem, pons, medulla
14
Q
External midbrain structures?
A
CN3, CN4, cerebral peduncles (descending motor tracts), superior colliculus (sub-cortical visual reflexes), inferior colliculus (sub-cortical auditory reflexes)
15
Q
Internal midbrain structures?
A
Cerebral aqueduct, periaqueductal gray area (PAG), nuclei for CN3&CN4, red nucleus, substantia nigra, descending motor tracts in cerebral peduncles
16
Q
Structures of the pons?
A
CN5 - CN8, motor tracts that descend from anterior pons, 4th ventricle
17
Q
Structures of the medulla?
A
CN9 - CN12, pyramids (descending motor tracts), pyramidal decussation (descending motor tracts that cross midline)
18
Q
What are the three vertical columns of the brainstem?
A
Tectum (posterior column), Tegmentum (middle column), Basis (anterior column)
19
Q
Location of tectum?
A
Posterior column of brainstem, everything posterior to cerebral aqueduct
20
Q
Structures of the tectum?
A
Superior colliculus, inferior colliculus
21
Q
Function of superior colliculus (tectum)?
A
Some visual info from eye connects directly, creates circuitry for visual reflexes (pupillary light relfex, orienting eyes toward/away from stimuli)
22
Q
Function of inferior colliculus (tectum)?
A
Some auditory info from ear connects directly, creates circuitry for auditory reflexes (loud sound -> shrug shoulders/duck head in protective position)
23
Q
Location of tegmentum?
A
Middle column of brainstem, everything between cerebral aqueduct/4th ventricle, and basis
24
Q
Structures of the tegmentum?
A
Reticular formation, ascending somatosensory tracts, nuclei of CN3 - CN12, descending motor tracts of spinal cord that originate from brainstem nuclei
25
Function of ascending somatosensory tracts in tegmentum?
Proprioception, light touch, pain and temp from body & head
26
Midbrain portion of the tegmentum holds nuclei of which cranial nerves?
CN3 & CN4
27
Pons portion of the tegmentum holds nuclei of which cranial nerves?
CN5 - CN8
28
Medulla portion of the tegmentum holds nuclei of which cranial nerves?
CN9- CN12
29
Which descending motor tracts of the spinal cord that originate from the brainstem do the tegmentum hold?
Rubrospinal tract, Tectospinal tract, Reticulospinal tract, Vestibulospinal tract
30
Where does the Rubrospinal tract originate?
Red nucleus in brainstem
31
Where does the Tectospinal tract originate?
Tectum in midbrain
32
Where does the Reticulospinal tract originate?
Reticular nuclei in lower 2/3 of brainstem
33
Where does the Vestibulospinal tract originate?
Vestibular nuclei in lower brainstem
34
Location of basis?
Most anterior part of brainstem
35
What are the three descending spinal tracts of the basis that begin in the motor cortices?
Corticospinal tract, Corticobulbar tract, Corticopontine tract
36
Corticospinal tract pathway of the basis?
Motor tracts that begin in primary motor cortex/end in spinal cord to supply muscles in the body
37
Corticobulbar tract pathway of the basis?
Motor tracts that begin in primary motor cortex/end in spinal cord to supply muscles in the face/head
38
Corticopontine tract pathway of the basis?
Motor tracts that begin in premotor cortices/end in cerebellum via the pontine nuclei
39
Location of the reticular formation?
Cluster of nuclei located in tegmentum throughout the length of the brainstem
*2 sections
40
Where is the rostral reticular formation?
Upper pons and midbrain
41
Where is the caudal reticular formation?
Lower pons and medulla
42
Overall function of the reticular formation?
Regulates and modulates most areas of the CNS
43
What syndrome is not completely understood yet is suggested to be d/t reticular formation dysfunction?
SIDS (Sudden infant death syndrome)
44
Function of the caudal reticular formation?
Modulates respiratory and CV nuclei of the brainstem, modulates motor functions, Modulates nociception pathways,
45
Motor function modulation by the caudal reticular formation?
Postural muscle tone, gait, horizontal eye movement, micturation (sphincter control), etc.
& complex physiologic motor reflexes: swallow, vomit, cough, sneeze, shivering, laughing, crying, etc.
46
Nociception function modulation by the caudal reticular formation?
Initial incoming nocicpetion from spinal cord/cortex stimulates reticular nuclei that send signals down spinal cord to inhibit incoming nociception/pain
47
What is the rostral reticular formation also known as?
Reticular activating system (RAS) or ascending reticular activating system (ARAS)
48
Function of rostral reticular formation? What could occur if it was damaged?
Modulates consciousness (levels)
*3 components of consciousness: alertness, awareness, attention
*damage to upper brainstem can result in potential coma/impaired consciousness
49
States of impaired consciousness?
Brain death, coma, vegetative state, minimal conscious state, stupor, lethargy, delirium, status epilepticus, akinetic mutism, sleep (normal or abnormal)
50
States that mimic impaired consciousness?
Locked in syndrome, dissociative disorders
51
Features of coma?
Remain unconscious, no meaningful response to stimuli, low glasgow scores, CNS cells still alive but metabolism significantly reduced, generally not permanent (after 2-4wks will either progress or digress into diff category)
52
Areas affected w/ coma?
Severely depressed: cortex, sub-cortical regions (diencephalon, upper brainstem/reticular nuclei), CNS arousal systems (RAS)
53
Reflexes that remain intact w/ coma?
Spinal cord reflexes, brainstem reflexes
54
Features of vegetative state?
Similar to coma: remain unconsious, no meaningful response to stimuli (slightly higher glasgow score), CNS cells still alive but metabolism significantly reduced
Different than coma: will display some sub-cortical function (sleep/wake cycle, some arousal reflexes)
55
Areas affected w/ vegetative state?
Severely depressed: cortex
Partially depressed: sub-cortical region
56
Reflexes that remain intact w/ vegetative state?
Spinal cord reflexes, brainstem reflexes, some arousal reflexes (arousal/open eyes or turn head to stimuli, random sounds/movement)
57
Features of brain death?
Extreme irreversible form of coma, no evidence of cortex, diencephalon, brain stem function ***ABSENT BRAINSTEM REFLEXES, metabolism/perfusion near zero
58
Areas affected w/ brain death?
Absent: cortex, sub-cortical arousal, brainstem functions
59
Reflexes that remain intact w/ brain death?
Spinal cord reflexes
60
What is the glasgow coma scale?
Clinical utility to indicate severity of acute brain injury, correlates w/ outcomes following brain injury
61
3 domains assessed w/ glasgow coma scale?
eye opening, verbal response, motor activity
62
Glasgow threshold of 3-8 indicates what?
Severe TBI (3 is lowest possible, wholly unresponsive), 8 is strongly considered for intubation)
63
Glasgow threshold of 9-12 indicates what?
Moderate TBI
64
Glasgow threshold of 13-15 indicates what?
Mild TBI (13 highest score: opens eyes spontaneously, oriented/alert, obeys commands)
65
What is the Uniform determination of death act (UDDA)?
Passed in 1980s, establishes neurological definition of death as "irreversible cessation of all functions of the brain including the brainstem"
66
Who developed guidelines for conducting brain death exams?
American Academy of Neurology (AAN)
67
Legal criteria to determine death vary from state to state, but in general require what?
Neuro evaluation by 2 independent physicians (if long period of time passed, 1 is usually sufficient)
68
1st step of establishing brain death (AAN outlines)?
Determine if pre-req's for brain death met:
-confirm coma not caused by meds/therapy/illicit drugs/toxins
-confirm no severe abnormalities in body temp, BP, or body chemistry (electrolytes/acid-base)
-confirm pt is mechanically ventilated
69
2nd step of establishing brain death (AAN outlines)?
Perform brainstem reflex tests: confirm all brainstem reflexes/responses absent
70
3rd step of establishing brain death (AAN outlines)?
Perform apnea tests: confirm no respiratory activity when ventilator removed
71
4th step of establishing brain death (AAN outlines)?
Perform ancillary tests if needed:
-if any of first 3 steps not met must be done
-confirms no cerebral bloodflow or metabolism of brain
-cerebral angiogram, cerebral scintigraphy, transcranial US, EEG, etc.
72
Brainstem reflex tests?
Noxious/deep pressure reflex, Pupillary light reflex, Vestibulo-ocular reflexes (VOR): head turning/caloric tests, Pharyngeal (gag) reflex/tracheal (cough) reflex
73
Noxious/deep pressure reflex procedure?
Apply deep pressure to condyles/TMJ, subraorbital area, or nail beds
If intact: grimace/facial muscle movement
74
CN's involved w/ Noxious/deep pressure reflex?
CN5 (V1, V2, V3): sensory part
CN7 (facial nerve): motor part
75
Pupillary reflex procedure?
Shine light in one eye, observe for direct and consensual response
76
CN's involved w/ pupillary reflex?
CN2: sensory, visual input
CN3: motor, parasympathetic portion, muscles of iris
77
Vestibulo-ocular (VOR) reflex head turning test procedure?
Manually rotate head to one side (eyes should rotate to opposite side)
Failure to rotate = doll's eyes
78
CN's involved w/ Vestibulo-ocular (VOR) reflex?
CN8: sensory, vestibular input from inner ear (semicircular canals)
CN 3, 4, 6: motor, extraocular muscles of eye
79
Vestibulo-ocular (VOR) reflex caloric test procedure?
Irrigate each ear w/ 60ml ice water, eye should move toward irrigated ear (tricks semicircular canals that head is being turned to opposite side being irrigated)
80
Corneal reflex test procedure?
Touch cotton swap to cornea, eyes should blink
81
CN's involved w/ corneal reflex?
V1 branch of CN5: sensory, sensation from cornea
CN7: motor, facial muscle (orbicularis oculi)
82
Pharyngeal gag reflex procedure?
Touch tongue depressor to posterior oropharynx, should produce gag (pharynx contracts)
83
CN's involved w/ pharyngeal gag reflex?
CN 9: sensation from oropharynx
CN10: motor, pharyngeal muscle
84
Tracheal (cough) reflex procedure?
Insert tracheal suctioning catheter to carina (should produce cough)
85
CN's involved w/ tracheal cough reflex?
CN10: sensation from trachea, motor supply of pharyngeal muscle
86
Which arteries supply the brainstem?
Vertebral artery, basilar artery, posterior cerebral artery
87
Vertebral artery supply of brainstem?
Small branches supply most of medulla
Branch that supplies lateral medulla/cerebellum: PICA (posterior inferior cerebellar artery)
88
Basilar artery supply of brainstem?
Pontine arteries (small branches that supply pons), AICA (anterior inferior cerebellar artery) - branches that supplies lower pons/cerebellum
89
Brainstem vascular syndromes that are caused by lesions of different arteries in the brainstem/cerebellum?
Weber's syndrome, Pure motor hemiparesis, Locked-in syndrome, Wallenberg's syndrome (lateral medullay syndrome)
90
Blood vessel involved with Webers syndrome?
Small branches of R or L PCA (unilateral stroke of anterior midbrain)
91
Blood vessel involved with motor hemiparesis?
R or L pontine arteries of basilar artery along R or L anterior pons (unilateral stroke of anterior pons)
92
Blood vessel involved with Locked-in syndrome?
Basilar artery & bilateral paramedian branches along pons (bilateral stroke of anterior pons)
93
What is the most common brainstem stroke?
Wallenberg Syndrome (lateral medullary syndrome)
94
Blood vessel involved with Wallenberg Syndome?
Vertebral artery, PICA, or small branches of PICA
*either directly or indirectly supply lateral medulla (unilateral stroke of lateral medulla)
95
Regions/structures damaged w/ Webers syndrome?
Basis of midbrain
-cerebral peduncle: damages descending motor tracts
-oculomotor nerve (CN3): damaged as exits front of midbrain
**may occasionally extend into substantia nigra
96
Regions/structures damaged w/ PMH?
Basis of pons
-descending motor tracts
97
Regions/structures damaged w/ Locked-in syndrome?
Basis of upper pons
-R and L descending motor tracts
98
Regions/structures damaged w/ Wallenberg syndrome?
Lateral medulla and maybe inferior cerebellum
-lesion damages structures of lateral medulla: nuclei of CN5, 8, 9, 10, sympathetic tract, spinothalamic tract
99
Clinical findings w/ Weber syndrome?
Contralateral hemipalegia, ipsilateral CN3 palsy (diplopia, ptosis, abnormal pupillary light reflex), Parkinsonian sx if substantia nigra affected
100
Clinical findings w/ PMH?
Contralateral hemiplegia
101
Clinical findings w/ Locked in syndrom?
Quadriplegia w/ intact sensation
*all motor function impaired except CN3 (& maybe CN4)
Unable to speak, move but can hear, see, think, and feel all somatosensory sensation
*vertical gaze or blinking may be spared since CN3/4 located above lesion
102
Locked in syndrome may mimic coma, but has what reflexes intact?
Spinal cord and brainstem reflexes, arousal/sleep-wake cycle, may have eye movement w/ purposeful response to stimuli
*cant move but can understand everything going on in environment
103
Clinical findings w/ Wallenberg syndrome d/t damage of CN5 nuclei/tracts?
Loss of pain/temp to the face
104
Clinical findings w/ Wallenberg syndrome d/t damage to spinothalamic tract?
Loss of pain/temp to the body
105
Clinical findings w/ Wallenberg syndrome d/t damage of CN8 vestibular nuclei?
Vertigo, N/V, nystagmus
106
Clinical findings w/ Wallenberg syndrome d/t damage of CN 9 &10?
Hoarseness, dysphagia
107
Clinical findings w/ Wallenberg syndrome d/t damage of sympathetic tract?
Horner's syndrome: ptosis, miosis, anhydrosis
108
Clinical findings w/ Wallenberg syndrome d/t damage of cerebellum/cerebellar peduncle?
Ataxia (lack of coordination)
