5. Motor System Flashcards
Where does the upper motor neuron in the corticobulbar tract end?
Brain stem
Cranial nerve nuclei
Where does the upper motor neuron in the corticospinal tract end?
Spinal cord
Give the pathway of the pyramidal system
- Motor cortex
- Genu/ posterior limb of internal capsule
- Cerebral peduncles
- Pons
- 85% decussate in pyramids of medulla, lateral corticospinal tracts
15% remain in anterior corticospinal tracts
What is an example of a disease which causes upper motor neuron lesion?
Stroke
Which side in relation to the lesion do symptoms appear after an upper motor neuron lesion?
Contralateral if in cerebral hemisphere
Ipsilateral if in spinal cord
What are the signs of an upper motor neuron lesion?
Initial weakness/paralysis Later spasticity Hyperreflexia Clonus Babinski's sign
What is clonus?
When a tendon is stretched, the attached muscle contracts rhythmically
What is a positive Babinski sign?
Toes extend when the side of the foot is touched
What are the symptoms of a lower motor neuron lesion?
Ipsilateral: Weakness Muscle wasting Fasciculations Hypotonicity Hyporeflexia
What disease causes lower motor neuron lesions?
Polio
Which cranial nerves have motor functions?
3, 4, 5c, 6, 7, 9, 10
What does an upper motor neuron of the facial nerve lead to?
Bilateral innervation means drooping only occurs below eyes
What does an lower motor neuron of the facial nerve lead to?
Facial muscles are damaged above and below the eye
Describe the rubrospinal pathway
- Cerebellum and cerebral cortex to red nucleus
- Ventral tegmental decussation
- Enter lateral white column of the spinal cord
- Gives stimulation to alpha and gamma motor neurons within the ventral grey horn
- Supply flexors
What reflex does the tectospinal tract control?
Response to visual stimuli
