Neuro Exam 3

Front 1

Brachial Plexus

Back 1

C5-T1- upper limb

Front 2

Lumbosacral plexus

Back 2

L2-S4 lower limb

Front 3

Primary motor cortex

Back 3

precentral gyrus, area 4, M1, layer V pyramidal neurons

Front 4

Motor cortex type

Back 4

heterotypical agranular

Front 5

Area 6

Back 5

Premotor, supplementary motor

Front 6

Areas 5, 7

Back 6

parietal motor

Front 7

Areas 32, 24

Back 7

Cingulate motor

Front 8

Lower Motor Neurons

Back 8

synapse directly with skeletal muscles
anterior horn
cranial n. motor neurons
includes cell body and axon

Front 9

Upper Motor Neurons

Back 9

synapse with other neurons, NOT muscles
corticospinal and corticonuclear tracts

Front 10

Damage to lower motor neurons

Back 10

flaccid paralysis
hypotonia, hyporeflexia, atrophy, fasciculations

Front 11

Damage to upper motor neruons

Back 11

spastic paralysis
hypertonia, hyperreflexia,
no immediate atrophy
(disuse atrophy appears later)

Front 12

Brown-Sequard Syndrome

Back 12

Upper limb-- lower motor neuron signs
Lower limb- upper motor neurons signs

Front 13

alpha motor neuron

Back 13

Large
flexors: posterior region of anterior horn
extensors: anterior region of anterior horn

Front 14

Gamma motor neuron

Back 14

small
flexors and extensors: distributed near alpha motor neurons

Front 15

Lower motor neuron function:

Back 15

influenced by:
sensory feedback from muscles
upper motor neurons that form the various descending tracts

Front 16

Large motor unit

Back 16

600-1000 muscle fibers/lower motor neuron
for HIGH levels of force

Front 17

small motor unit

Back 17

10-100 muscle fibers/lower motor neuron
for LOW levels of force, rapid contraction and fine control

Front 18

size principle

Back 18

small motor units recruited first in muscle contraction

Front 19

motor unit

Back 19

motor neuron plus all the muscle fibers it innervates

Front 20

muscle spindles

Back 20

provide sensory input from muscles to lower motor neurons

Front 21

Static nuclear bag fiber

Back 21

mechanoreceptors respond to change in muscle length

Front 22

Dynamic nuclear bag fiber

Back 22

mechanoreceptors respond to RATE of change in muscle length

Front 23

Nuclear chain fiber

Back 23

mechanoreceptors respond to change in muscle length

Front 24

GTO

Back 24

mechanoreceptor that responds to change in muscle/tendon tension
type Ib-- inhibit alpha motor neurons to same muscle
higher activation threshold

Front 25

Alpha-Gamma coactivation

Back 25

voluntary movement-- activates alpha and gamma motor neurons simultaneously

Front 26

Spasticity

Back 26

increased resistance to passive movement

Front 27

Hypertonicity

Back 27

muscles exhibit increased tone but feel "weak" to patient

Front 28

Hyperreflexia

Back 28

deep tendon reflexes are more brush (0 to 4+ scale)

Front 29

Clonus

Back 29

repetitive oscillation between flexion and extension at a single joint due to hyperactive flexor and extensor reflexes

Front 30

Babinski sign

Back 30

great toe (inverted planar flexion) can be accompanied by "triple flexion"-- dorsiflexion at ankle, knee, hip

normal in children

Front 31

Disuse atrophy

Back 31

develops slowly over a period of weeks to months to years

Front 32

corticonuclear signs of V

Back 32

typically no jaw deviation
deviation towards weak side

Front 33

corticonuclear signs of VII

Back 33

contralateral, lower face sags

Front 34

corticonuclear signs of X

Back 34

uvula deviates to strong side
hoarse voice, swallowing difficulty

Front 35

corticonuclear signs of XII

Back 35

tongue deviates to weak side

Front 36

corticonuclear signs of XI

Back 36

SCM, trapezius weak (I/L) side head cannot be turned C/L

Front 37

upper motor neuron lesion

Back 37

spasticity, hypertonia, hyperreflexia, clonus, babinski

Front 38

lower motor neuron lesion

Back 38

flaccidity, hypotonia, hyporeflexia, fasciculations, atrophy