Spinal Cord Compression

Question 1

what is monoparesis

Answer 1

weakness of one limb

Question 2

what is paraparesis

Answer 2

weakness of both legs

Question 3

what is hemiparesis

Answer 3

weakness of one side of the body

Question 4

what is quadraparesis

Answer 4

weakness of all four limbs

Question 5

what is hemiplegia

Answer 5

paralysis of one side of the body

Question 6

what is paraplegia

Answer 6

paralysis of both legs

Question 7

in UMN what muscular patterns are seen in the legs and arms

Answer 7

legs:
plantiflexion>dorsiflexion
adduction>abduction

arms:
adduction>abduction

Question 8

which muscles are affected in demyelinating polyneuropathy

Answer 8

proximal and antigravity muscles

Question 9

which muscles are affected in length dependant axonal neuropathy

Answer 9

distal weakness

Question 10

which food can exaggerate muscular pain cause by statins

Answer 10

grapefriut juice can increase plasma concentration of atorvastatin and simvastatin

Question 11

what is seen on biopsy of polymyositis

Answer 11

inflammatory cells surround and infiltrate muscle

Question 12

what is seen on biopsy of dermatomyositis

Answer 12

inflammatory cells surround blood vessels in muscles

pts presents with rash over hands and face
there is an association with malignancy in adults

Question 13

what is seen on biopsy of inclusion body myositis

Answer 13

rimmed vacuole in muscle fibres

tends to occur in elderly pts
affects proximal leg muscles and long finger flexors

Question 14

bilateral sciatia is indicative of what

Answer 14

cauda equina

Question 15

which type of sensory and motor neurone are activated in myotactic reflexes

Answer 15

muscle spindles activate afferent Ia fibres
these synapse onto inhibitory interneurones which inhibits the alpha-motor neurone to the heteronymous muscle
the afferent Ia fibre also synapses with alpha motor neurone in the affected muscle and causes contraction

Question 16

what are Renshaw cells and name a toxin which affects them

Answer 16

inhibitory neurones excited by alpha motor neurones,
they inhibit synergistic alpha motor neurones ensuring the reflex is transient (provide negative feedback)
work via GLYCINE
glycine release is inhibited by tetanus toxin

Question 17

which afferent and efferent fibres are used in the Golgi tendon reflex

Answer 17

afferent Ib synapses onto inhibitory interneurone which inhibits:
efferent alpha

Question 18

what do gamma motor neurones do

Answer 18

regulate tension in muscle spindles

Question 19

what type of tract is the corticospinal tract where does it originate
where does it decussate

Answer 19

descending from Pyramidal (Betz) cells through internal capsule
80% Decussates at the medullary pyramids this forms the lateral CS tract and controls distal limb muscles

the remaining 20% descend ipsilaterally and forms the ventral CS tract
they then cross the midline before synapsing onto motor neurones for proximal limb and axial muscles

Question 20

what is the purpose of the primary somatosensory cortex

Answer 20

receives sensory input via the thalamus and sends descending fibres to sensory regions to filter signals

Question 21

what is the purpose of the premotor area

Answer 21

planning of intended movements

eg movements requiring visual guidance

Question 22

what is apraxia

Answer 22

inability to produce a specific motor act even thought sensory and motor pathways remain intact

Question 23

which descending tract is involved in the modulation of spinal extensor reflexes

Answer 23

reticulospinal

Question 24

which descending tract is involved in posture and balance

Answer 24

vestibulospinal

Question 25

which descending tract is involved in direct head movements in response to sitmuli

Answer 25

tectospinal

Question 26

which descending tract is involved in facilitating flexor motor neurones

Answer 26

rubrospinal

Question 27

what are the 3 main sensory ascending tracts

Answer 27

``` 1) SPINOTHALAMIC --> THALAMUS pain touch temp pressure 2) SPINOCEREBELLAR --> CEREBELLUM proprioception 3) DORSAL COLUMNS --> THALAMUS joint position and fine discriminatory touch ```

Question 28

how do the fibres of the spinothalamic pathway decussate

Answer 28

afferents enter the spinal cord into the dorsal horn, they then traverse the spinal cord and ascend in either the anterior or lateral ST tract anterior - pain and temp lateral - crude touch

Question 29

how do the fibres of the dorsal columns decussate

Answer 29

enter the spinal cord white matter posteriorly and ascend ipsilaterally in the dorsal columns. Synapse in medulla, second order neurones then decussate and ascend in the medial lemniscus to thalamus

Question 30

what are the signs of spastic paraparesis

Answer 30

increased tone and clonus weakness atrophy and contractors extensor plantars

Question 31

what are the causes of spastic paraparesis

Answer 31

``` demyelination cerebral palsy cord compression MND spinal cord infartion vasculitis myelitis subacute combined degeneration of the cord syringomyelia syphilis ```

Question 32

what is Friedreich's ataxia

Answer 32

``` hereditary spinocerebellar ataxia (AR) features: - kyphoscoliosis - pes cavus - ataxia - apastic paraparesis - peripheral neuropathy - cerebellar signs -cardiomyopathy - diabetes mellitus ```