TESTING MUSCLE FUNCTION Flashcards
How is the motor system divided?
into the pyramidal and extrapyramidal systems.
what is the pyramidal tract?
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
what is the extrapyramidal tract?
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
how would an upper motor neurone lesion present?
as muscle weakness, an increase in muscle tone, exaggerated reflexes, clasp knife response, babinski sign
what is the clasp knife response?
a Golgi tendon reflex with a rapid decrease in resistance when attempting to flex a joint,
how does an upper motor neurone lesion present?
muscle weakness, reduced muscle tone, diminished reflexes, muscle atrophy and muscle fasciculation
what is muscle fasciculation?
muscle twitches
how does an extrapyramidal lesion present?
dystonia (continuous spasms), akathisia (motor restlessness), Parkinsonism (rigidity, bradykinesia and tremors), dyskinesia (irregular jerky movements)
how do cerebellar lesions present?
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).
what are some causes of upper motor neurone lesions?
stroke
multiple sclerosis
traumatic brain injury
cerebral palsy
what are some causes of lower motor neurone lesions?
Bell’s palsy
Guillan-Barre syndrome
motor neurone disease
what are some causes of extrapyramidal lesions?
anti-dopaminergic drugs
meningitis
traumatic brain injury
Parkinsonism
what are some causes of cerebellar lesions?
bleeds
stroke
tumours
what is Brown-sequard syndrome?
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)
what is Anterior Cord syndrome?
loss of pain and temperature sensation but with a preserved fine touch and proprioception
what is Central Cord syndrome?
variable sensory loss with motor deficits being greater in the upper limbs over lower limbs
what is isometric muscle contraction?
when the muscle is activated but there is no movement
what is isotonic muscle contraction?
contraction where muscle is shortening (concentric) or lengthening (eccentric)
what is isokinetic muscle contraction?
the velocity of the muscle contraction remains constant while the length of the muscle changes.
what are contractures?
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.
in terms of clinical skills, what do we look for when considering muscle function?
muscle hypertrophy, muscle atrophy, fasciculations, contractures, tremors
what sorts of muscle power testing can we do?
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
what is the plantar reflex? which nerve is it innervated by?
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.
which nerve root supplies the ankle jerk reflex?
S1/S2
