Impairment of motor control - clinical signs and patterns Flashcards
Within the frontal lobe how does the signal to move start?
- Prefrontal cortex will initiate idea to move (tells premotor cortex steps required to move)
- Premotor cortex will then organise and sequence movements
- Primary motor cortex send signals down spinal cord
- these synapse with motor neurones
How does the signal to move progress after leaving the cortex (descending motor pathways)?
- From cortex signal descends through the internal capsule
- form upper motor neurones (corticospinal tracts)
- these neurones pass through the pons
- at the level of the medulla the neurones cross to form lateral corticospinal tract
- the lateral corticospinal tracts then synapse with the lower motor neurones or cranial nerves of the brainstem
What makes up a lower motor neurone?
peripheral nerve connecting anterior horn of spinal cord /brainstem to muscle
What is the function of Alpha motor neurones?
voluntary muscle contraction and myostatic stretch reflex
What is the function of gamma motor neurones?
regulate muscle tone and maintain proprioception
What are the possible descending motor pathways?
Corticospinal tracts
Rubrospinal
Vestibulospinal
Reticulospinal
What sets the baseline muscle tone?
- Spinal Neurones
- Brainstem motor areas
(these are then overridden by cortex exerting inhibitory signals)
What does Arevflexic mean
lack of a reflex response
What does Paraparesis and paraplegia mean?
Paraparesis - weakness of legs
Paraplegia - Complete weakness of the legs
What does parasthesia mean?
Abnormal sensation
What does Hemiparesis mean?
weakness in half body
What does Quadra/tetraparesis mean?
Weakness of arms and legs
What does Myelo- mean?
of the spinal cord
What does radiculo- mean
of the nerve roots
What does ataxia mean?
lack of co-ordination of limb movements and/or gait
What will result from a lesion above the medulla?
contralateral hemiplegia
- pattern of flexed upper limbs and extended lower limbs
- arms adduct, foot plantar flexes and leg extends
What will result from a lesion below the medulla?
Cervical - quadriplegia
Thoracic/lumbar - paraplesgia
Hemisection of cord - Brown-Sequard syndrome
What are the common signs of UMN?
- Increased tone/spasticity
- Clonus
- Hyperreflexia
- Babinski sign/extensor plantar
Where is the most likely lesion location if there is spastic paraparesis in 4 limbs?
above C5 usually complete as very traumatic causes e.g. car crash