Spinal Cord Lesions Flashcards
What are the causes of hypotonia?
If any part of the monosynaptic stretch reflex arc is interruped.
Occurs in cerebellar disease as a result of diminished influence on the γ motor neurons from cerebellum.
What are the causes of hypertonia?
Lesion involving the supraspinal centers or their descending tracts but not the corticospinal tract.
Or it may be due local excitation of stretch reflex by sensory irritation at segental level.
What are tremors?
Rhythmic involuntary movements that result from contraction of opposing muscle roups.
What are the categories of tremors?
Resting tremors
Action tremors
What are resting tremors?
Resting tremor occurs when the muscle is relaxed, such as when the hands are resting on the lap.
What are action tremors?
Action tremor occurs with the voluntary movement of a muscle.
What is intention tremor?
Intention tremor is produced with purposeful movement toward a target, such as lifting a finger to touch the nose. Typically the tremor will become worse as an individual gets closer to their target.
What is postural tremor?
Postural tremor occurs when a person maintains a position against gravity, such as holding the arms outstretched.
What is kinetic tremor?
Kinetic tremor is associated with any voluntary movement, such as moving the wrists up and down or closing and opening the eyes.
What is task-specific tremor?
Task-specific tremor only appears when performing highly-skilled, goal-oriented tasks such as handwriting or speaking.
What is isometric tremor?
Isometric tremor occurs during a voluntary muscle contraction that is not accompanied by any movement such as holding a heavy book or a dumbbell in the same position.
What are spasms?
Spasms are sudden, involuntary contractions of large group of muscles.
Examples are seen in paraplegia and are due to lesions involving the descending tracts (not the corticospinal tracts)
What is athetosis?
Involuntary, disrhythmic, slow, continuous movements that are same in the same patients and disappear during sleep. They impede voluntary movements. It happens in lesions.
What happens in athetosis?
Lesion of corpus striatum
What is chorea?
Involuntary, continuous, rapid, jerky, coarse, purposeless movements that occur in sleep. It is due to corpus striatum lesions.
