473 MT 1 Flashcards Preview

Neuroanatomy > 473 MT 1 > Flashcards

Flashcards in 473 MT 1 Deck (81):
1

diencephalon

thalamus and hypothalamus + associated structures

2

hindbrain

pons and cerebellum and medulla

3

ventral
dorsal
rostral
caudal

ABOVE MIDBRAIN
toward earth=inferior
toward sky=superior
toward snout=anterior
toward tail=posterior

BELOW MIDBRAIN
anterior
posterior
superior
inferior

4

multipolar
bipolar

=multiple axons and dendrites
=1 axon and 1 dendrite arising from cell body

5

cauda equina

=collection of nerve roots where spinal chord ends

6

lower motor neuron symptoms

weakness, atrophy, fasciculations, hypotonia and hyporeflexia

7

upper MN symptoms

"spastic paralysis"-motion starts and then gives way
weakness
hyperreflexia
hypertonicity-spasticity and rigidity
positive Babinski sign

8

somatotopic organization main points

-foot and leg in midline, knee @ corner
-next is trunk
-then shoulder-->upper limb
-neck, face, tongue

9

epi-

means above

10

what level of brainstem is cerebellum at?

pons

11

meninges in brain

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

falx cerebri
tentorium cerebelli
where they meet

meningial layers of dura
separates two hemispheres
separates cerebellum and cerebrum
triangular notch called tentorial notch/incisura @ midbrain (which connects them all)

13

tentorial notch

=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

arachnoid granulations

arachnoid adheres to inner surface of dura
places where arachnoid mater bulges through dura

15

pia mater

adheres to surface of brain and follows gyri and sulci

16

potential spaces b/t meninges vs. actual space

epidural-skull and periosteal dura
sub-dural-meningial dura and arachnoid

sub-arachnoid space-b/t arachnoid and pia
-contains CSF

17

epidural hematoma

-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

subdural hematoma

-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

chronic bleeding in the brain?

looks darker on scans
older adults sometimes
bridging veins taught from aging and more easily sheared

20

subarachnoid hematoma

-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

meninges in spinal chord

-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

denticulate ligaments

ligaments that hold the spinal chord in space
connect pia to dura

23

filum terminale

lig that anchors spinal chord

24

CSF

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