473 MT 1 Flashcards
1
Q
diencephalon
A
thalamus and hypothalamus + associated structures
2
Q
hindbrain
A
pons and cerebellum and medulla
3
Q
ventral
dorsal
rostral
caudal
A
ABOVE MIDBRAIN toward earth=inferior toward sky=superior toward snout=anterior toward tail=posterior
BELOW MIDBRAIN anterior posterior superior inferior
4
Q
multipolar
bipolar
A
=multiple axons and dendrites
=1 axon and 1 dendrite arising from cell body
5
Q
cauda equina
A
=collection of nerve roots where spinal chord ends
6
Q
lower motor neuron symptoms
A
weakness, atrophy, fasciculations, hypotonia and hyporeflexia
7
Q
upper MN symptoms
A
"spastic paralysis"-motion starts and then gives way weakness hyperreflexia hypertonicity-spasticity and rigidity positive Babinski sign
8
Q
somatotopic organization main points
A
- foot and leg in midline, knee @ corner
- next is trunk
- then shoulder–>upper limb
- neck, face, tongue
9
Q
epi-
A
means above
10
Q
what level of brainstem is cerebellum at?
A
pons
11
Q
meninges in brain
A
PAD (inside to outside) pia arachnoid dura -periosteal layer adheres to skull -meningial layer fuses w/periosteal layer except where it extends to separate hemispheres or cortex from cerebellum
12
Q
falx cerebri
tentorium cerebelli
where they meet
A
meningial layers of dura
separates two hemispheres
separates cerebellum and cerebrum
triangular notch called tentorial notch/incisura @ midbrain (which connects them all)
13
Q
tentorial notch
A
=where falx cerebri and tentorium cerebelli meet and form an opening
-potential site of injury for midbrain (swelling or tumor could displace or damage it)
14
Q
arachnoid granulations
A
arachnoid adheres to inner surface of dura
places where arachnoid mater bulges through dura
15
Q
pia mater
A
adheres to surface of brain and follows gyri and sulci
16
Q
potential spaces b/t meninges vs. actual space
A
epidural-skull and periosteal dura
sub-dural-meningial dura and arachnoid
sub-arachnoid space-b/t arachnoid and pia
-contains CSF
17
Q
epidural hematoma
A
- bleeding above dura: bulges into skull
- lens shaped b/c of more anchored parts of dura
- arterial bleed, fast spreading (heart pumping blood)
- can cross midline
- common b/c of middle meningeal artery being outside the dura and b/t two plates of thin skull
- common w/temporal bone fracture
18
Q
subdural hematoma
A
- damage to bridging veins b/t arachnoid and meningeal dura (drain to dural sinuses)
- commonly b/c of shear by acceleration of the brain
- slow to develop
- crescent shaped and more widely distributed-arachnoid less anchored to dura so it get’s pulled away more easily
- does not cross midline b/c of falx cerebri
19
Q
chronic bleeding in the brain?
A
looks darker on scans
older adults sometimes
bridging veins taught from aging and more easily sheared
20
Q
subarachnoid hematoma
A
- blood disperses into CSF from damaged arteries/veins w/in subarachnoid space and clogs arachnoid villi
- –>pressure and herniation and death
- commonly from aneurism or major trauma
- blood can be seen in sulci
21
Q
meninges in spinal chord
A
- only meningeal layer of dura b/c periosteal fuses to periosteum as it passes through foramen magnum
- pia wraps around spinal chord
- epidural fat lies in b/t dura and periosteum in b/t ligaments that run along the bone
22
Q
denticulate ligaments
A
ligaments that hold the spinal chord in space
connect pia to dura
23
Q
filum terminale
A
lig that anchors spinal chord
24
Q
CSF
A
made in choroid plexus
protection, buoyancy, nutrient and hormone transfer
25
foramen of munroe
-connects 3rd and lateral ventricles
26
foramen of luschka
2 lateral foramen coming out of 4th ventricle
| -connects subaracnoid spaces of brain to 4th ventricle
27
cerebral aqueduct
connects 3rd and 4th ventricles
28
foramen of magendie
connects 4th ventricle to subarachnoid space of spinal chord
29
how much CSF is made/day
500 CCs-3x turnover since space holds 150 CCs
30
cistern magna
opening @ bottom of spinal chord
31
lumbar cista
space where vertebral column continues w/out spinal chord
| -contains CSF and nerve roots (lumbar puncture
32
rexed's laminae
=divisions of grey matter in spinal chord
| -IX contains 2 regions of motor nuclei-medial and lateral
33
somatotopic organization of ventral horn
more proximal muscles are more medial
| more distal are more lateral
34
conus medullaris
end of spinal chord at L1/L2 vertebre
35
cervical enlargement
| lumbar enlargement
C3-T1
| L1-S2
36
where is there more white matter in the spinal chord?
higher up--all nerves projecting
37
myotome
=the muscles innervated by a single spinal segment
38
deltoid
biceps, brachioradialis, brachialis
triceps
C5, C6
C5, C6
C7
39
hand muscles
C7, C8, T1
40
wrist extenders
C6
41
chest muscles
T2-T8
42
abdominal muscles
T7-T12
43
leg muscles
L1-L5
knee extensors L4
dorsiflexors L5
plantar flexors S1
44
bowel, bladdar muscles
sacral nerves
45
paresis
weakness but some preserved function
46
characteristics of high steppage gait
1. excessive flexion of knee on ipsilateral side
2. lack of ankle dorsiflexion on ipsilateral side
3. foot lands toe first
ie damage to L5 (dorsiflexors)
47
what causes fasciculations?
denervation causes hypersensitivity in the muscle b/c it's not receiving input and causes individual fibers to fire in response to other things
-at muscle level
48
why does lower MN damage result in atrophy?
b/c they provide trophic factors for life and growth
49
what is a normal reflex?
2 (1 is dec, 0 is absent)
| 4 and 5 are abnormal clonus
50
hypotonia
tonic activity decreased
| -seen in less resistance to passive at endpoints of a joint's range of motion
51
hypertonia
more resistance in middle of passive movement
52
3 places lower MN's can be effected
damage to any of the 3 areas:
- motor nuclei in anterior horn gray matter of spinal chord
- ventral nerve roots (called radiculopathy)
- spinal nerves
53
poliomyelitis
- attacks anterior horn motor neurons
| - mostly lumbar and sacral, sometimes involves thoracic which can affect breathing
54
what would you expect if there was spinal chord damage involving the anterior horn?
how would this have happened?
lower MN symptoms in muscles innervated by axons AT that level
upper MN symptoms in muscles innervated by levels below the injury
-spinal chord lesion
-disk herniation
-tumor
55
what exception to the effect of disk herniation for lumbar disk exists?
- it can compress that level and the one below it
- the intervertebral foremen is big enough in this region that it can also impinge on nerve below
- more central will affect more nerves travelling farther down
56
mechanisms of injury for ventral and spinal roots
compression, traction, laceration, or entrapment
57
corticospinal tract
upper motor neuron in precentral gyrus in primary motor cortex, axon decussates @ pyramids in medulla and continues to it's spinal level
lower MN synapses in anterior horn of spinal chord
-directly or indirectly (through interneurons)
58
cortico-spinal tracts as they travel through brain
fan-like projection fibers in the cortex=CORONA RADIATA
as they converge near the thalamus=INTERNAL CAPSULE
at the midbrain level=BASIS PEDUNCULI
at the anterior medulla=PYRAMIDS
where they cross at cervical medullary junction=PYRAMIDAL DECUSSATION
59
internal capsule
V shape w/point at midline
- anterior limb and posterior limb (on each L and R side)
- posterior limb contains upper motor neurons from cortex (ie corticospinal tract)
- genu=where they meet
60
how many cortico-spinal tracts do we have?
lateral-85%
anterior-15%
-each in the columns named after them
61
lateral corticospinal tracts
-primarily distal (hand and feet) muscles (contra-lateral side)
-terminate at all levels of the spinal chord, cervical and lumbro-sacral enlargements primarily
called pyramidal tract also
62
where do lateral corticospinal upper motor neurons synapse?
they enter the anterior horn at the level of the spinal chord they will innervate and synapse w/interneurons in grey matter
-more laterally (they control distal muscles primarily)
63
anterior cortico-spinal tracts
- primarily axial muscles (neck and trunk)
- MAY divide and cross at the spinal level (anterior commissure), some don't
- ie fibers do not decussate, some bifurcate and cross
- controls muscles bilaterally
- terminate in cervical and upper thoracic spinal chord
64
cortico-bulbar tract
UMN: facial region of cortex to nuclei in pons
LMN: in pons (lower motor nuclei called facial nuclei extends as CNVII facial nerve)
65
how are facial muscles controlled?
CN VII travels ipsi-laterally to muscles
- UMNs travel bilaterally for muscles above eyes
- UMNs travel contra-laterally to CN VII for muscles below eyes
66
what is bell's palsy?
- inflammation of the facial nerve
- affects muscles on entire side of face on ipsilateral side of inflammation
- RARELY inflammation occurs bilaterally
- inability to close the eye, taste is affected, etc.
- full recovery takes 3-6 mo and people sometimes have persistent symptoms
67
what is the somatotopic organization at the midbrain level/basis pedunculi?
face is medial, then arm, then trunk, leg is lateral
| -(after 2 90 degree turns)
68
what is the somatotopic organization of the internal capsule?
face forward (after 90 degree turn), posterior is legs
69
rubrospinal tract
from red nucleus (midbrain) to spinal chord in lateral column
- decussation at midbrain level
- terminate in cervical chord
- contralaterally controls limbs: facillatates flexor muscle tone and inhibits extensor muscle tone (limited voluntary control)
70
reticulospinal tract
reticular formation (throughout brainstem) to spinal chord in ventral column
- does not decussate
- balance, startle reflex, general muscle tone
71
vestibulospinal tract
from 4 vestibular nuclei (pons and medulla) to spinal chord
lateral vestibular nuclei: to distal limbs on ipsilateral side
-facillatates extensor muscle tone
medial and inferior: to mostly axial muscles on both sides
-bilaterally controls vestibular reflexes
-NO decussation
72
tectospinal tract
from superior colliculus (midbrain) to spinal chord
| -for coordination of hand/eye movements
73
where can upper MNs be injured?
-in the upper motor nuclei in the motor cortex
-in axons descending through brain, brainstem, or spinal chord
ie, ipsilateral lesion @ spinal level or contra-lateral at cortical level will affect distal muscles on that side
74
how does type of tone help identify location?
- de-corticate posture-lesion above midbrain
- involves rubrospinal tract
- flexion of contralateral hand and extension of leg
- de-cerebrate posture-lesion is below midbrain
- involves vestibulo-spinal tract
75
babinski reflex
dorsiflextion of big toe and fanning=positive sign
| =injury to corticospinal tract
76
hemiplegic gait is typical of what injury?
UMN lesion
- flexion of contralateral arm and extension of leg
- leg, knee, and ankle extended throughout walking
- leg swings through w/hip hiking and then circumduction and arm is held flexed
77
causes of UMN lesions
- injury to cortex (stroke, tumor, trauma)
- damage to internal capsule or cerebral peduncles (hemiplegic type injury b/c axons for all regions travel together)
- spinal chord lesion or compression (lateral column) (symptoms on ipsilateral side)
- diseases attacking UMNs
78
which side would you expect symptoms on if there was damage to the internal capsule?
contra-lateral
| whole side
79
what type of spinal chord injuries cause upper and lower motor neuron damage?
where do the symptoms occur?
- if just lateral part is damaged, upper motor neurons are affected below that level
- if it extends into grey matter, there are lower motor neuron symptoms for that level
80
PLS
- unknown origin
- degeneration of UMN's (UMN symptoms)
- progressive (from legs up) but not fatal
81
ALS
lou Gehrig's disease
UMN and LMN degeneration
-unknown origin, potentially genetic
-fatal in 2-4 years, affects breathing, swallowing, speaking
