TESTING MUSCLE FUNCTION

Question 1

How is the motor system divided?

Answer 1

into the pyramidal and extrapyramidal systems.

Question 2

what is the pyramidal tract?

Answer 2

They originate in the cerebral cortex, carrying motor fibres to the spinal cord and brain stem. They are responsible for the voluntary control of the musculature of the body and face
e.g. lateral and anterior corticospinal tracta

Question 3

what is the extrapyramidal tract?

Answer 3

These tracts originate in the brain stem, carrying motor fibres to the spinal cord. They are responsible for the involuntary and automatic control of all musculature, such as muscle tone, balance, posture and locomotion
e.g. rubrospinal, reticulospinal, olivaryspinal and vestibulospinal tracts

Question 4

how would an upper motor neurone lesion present?

Answer 4

as muscle weakness, an increase in muscle tone, exaggerated reflexes, clasp knife response, babinski sign

Question 5

what is the clasp knife response?

Answer 5

a Golgi tendon reflex with a rapid decrease in resistance when attempting to flex a joint,

Question 6

how does an upper motor neurone lesion present?

Answer 6

muscle weakness, reduced muscle tone, diminished reflexes, muscle atrophy and muscle fasciculation

Question 7

what is muscle fasciculation?

Answer 7

muscle twitches

Question 8

how does an extrapyramidal lesion present?

Answer 8

dystonia (continuous spasms), akathisia (motor restlessness), Parkinsonism (rigidity, bradykinesia and tremors), dyskinesia (irregular jerky movements)

Question 9

how do cerebellar lesions present?

Answer 9

with ipsilateral loss of co-ordination, past pointing, disdiadochokinesis (impaired ability to perform alternating movements), ataxic gait (wide base/staggering), nystagmus (uncoordinated eye movement) and dysarthria (speech inability).

Question 10

what are some causes of upper motor neurone lesions?

Answer 10

stroke
multiple sclerosis
traumatic brain injury
cerebral palsy

Question 11

what are some causes of lower motor neurone lesions?

Answer 11

Bell’s palsy
Guillan-Barre syndrome
motor neurone disease

Question 12

what are some causes of extrapyramidal lesions?

Answer 12

anti-dopaminergic drugs
meningitis
traumatic brain injury
Parkinsonism

Question 13

what are some causes of cerebellar lesions?

Answer 13

bleeds
stroke
tumours

Question 14

what is Brown-sequard syndrome?

Answer 14

damage to one half of the spinal cord that causes loss of ipsilateral fine touch and proprioception and loss of contralateral pain and temperature sensation
(diminished sensory loss)

Question 15

what is Anterior Cord syndrome?

Answer 15

loss of pain and temperature sensation but with a preserved fine touch and proprioception

Question 16

what is Central Cord syndrome?

Answer 16

variable sensory loss with motor deficits being greater in the upper limbs over lower limbs

Question 17

what is isometric muscle contraction?

Answer 17

when the muscle is activated but there is no movement

Question 18

what is isotonic muscle contraction?

Answer 18

contraction where muscle is shortening (concentric) or lengthening (eccentric)

Question 19

what is isokinetic muscle contraction?

Answer 19

the velocity of the muscle contraction remains constant while the length of the muscle changes.

Question 20

what are contractures?

Answer 20

they develop when normally elastic tissues such as muscles or tendons are replaced by inelastic tissues (fibrosis). This results in the shortening and hardening of these tissues, ultimately causing rigidity, joint deformities and a total loss of movement around the joint.

Question 21

in terms of clinical skills, what do we look for when considering muscle function?

Answer 21

muscle hypertrophy, muscle atrophy, fasciculations, contractures, tremors

Question 22

what sorts of muscle power testing can we do?

Answer 22

passively flexing and extending each joint.
testing for CLONUS (involuntary muscle spasms)
hypotonia and hypertonia
general function tests
resistance tests]
myotome testing
deep tendon reflexes

Question 23

what is the plantar reflex? which nerve is it innervated by?

Answer 23

gradually drag your finger along the edge of the sole of the foot, the toes will dorsiflex. Abnormal is a positive Babinski response and suggests an UMN lesion or recent epileptic seizures. This reflex is mediated by S1/S2 nerve roots.

Question 24

which nerve root supplies the ankle jerk reflex?

Answer 24

S1/S2

Question 25

which nerve root supplies the knee jerk reflex?

Answer 25

L3/L4

Question 26

which nerve root supplies the Bicep reflex?

Answer 26

C5/C6

Question 27

which nerve root supplies the supinator reflex?

Answer 27

C5/C6

Question 28

which nerve root supplies the tricep reflex?

Answer 28

C7/C8

Question 29

how can we test for unconscious proprioception?

Answer 29

Romberg’s test, gait, finger-nose test, dysarthria, dysdiadochokinesis, nystagmus, heel-shin test

Question 30

what is spasticity?

Answer 30

increased muscle tone as you move the limb. the faster the muscle stretches, the greater the increase in muscle tone

Question 31

what is rigidity?

Answer 31

constant resistance to movement that is not associated with stretch velocity

Question 32

how do you elicit the knee jerk reflex?

Answer 32

Lie the patient flat and tell them to relax and that you will tap them just below the knee with ‘this’ (show them the hammer). Don’t tell them it’s a hammer, this can cause apprehension!
Place you arm under one knee and lift it from the bed while supporting your hand on the patient’s other knee. You can lift up both knees together if you like.
Locate the patellar tendon between the tibial tubercle and the lower border of the patella
Swing the patellar hammer so that it falls onto the patellar tendon
At the same time watch for a contraction in the quadriceps muscle.

Question 33

describe the Oxford strength scale?

Answer 33

0: No visible muscle contraction
1: Visible muscle contraction with no or trace movement
2: Limb movement, but not against gravity
3: Movement against gravity but not resistance
4: Movement against at least some resistance supplied by the examiner
5: Full strength