Pyramidal System: Spastic Paralysis

A comprehensive set of flashcards covering key vocabulary and concepts related to the pyramidal system and motor neuron functions, as discussed in the lecture.

Pyramidal System

A system composed of upper motor neurons that originates in the cerebral cortex, responsible for the initiation and regulation of voluntary motor movements.

Corticospinal Tract

A major tract of the pyramidal system that transmits signals from the upper motor neurons in the primary motor cortex to lower motor neurons.

Pyramidal Decussation

The crossing of the corticospinal tract fibers to the contralateral side in the caudal third of the medulla.

Upper Motor Neuron (UMN)

Neurons that originate in the brain, synapse with lower motor neurons in the spinal cord, involved in voluntary movement.

Lower Motor Neuron (LMN)

Neurons that connect the central nervous system to muscles, responsible for the execution of movements.

Corticobulbar Tract

A tract that originates from the primary motor cortex, responsible for movements of cranial nerves related to functions such as chewing, speech, and swallowing.

Spastic Paralysis

A condition caused by upper motor neuron lesions, characterized by increased muscle tone and exaggerated reflexes.

Flaccid Paralysis

A condition caused by lower motor neuron lesions, characterized by decreased muscle tone and atrophy.

Babinski Sign

An abnormal reflex indicating upper motor neuron damage, exhibited by the extension of the big toe upon stimulation of the foot.

Capsular Strokes

Strokes that affect the posterior limb of the internal capsule, leading to contralateral paralysis and hypertonia.

Muscle Tone

The degree of stiffness or resistance of a muscle at rest, which can be increased in UMN lesions or decreased in LMN lesions.

Clasp-Knife Response

A type of reflex response characterized by initial resistance followed by sudden relaxation during passive movement.

Sacral Sparing

Preservation of motor and sensory function in the sacral segments of the spinal cord despite injury affecting other levels.

Spinal Shock

Temporary loss of reflexes following spinal cord injury, typically lasting from 1 to 6 weeks.

Alternating Hemiplegia

A condition where UMN damage is contralateral and LMN damage is ipsilateral, often due to brainstem lesions.

Proprioception

The sense that allows awareness of body position and movement, crucial for coordination and balance.

Premotor Cortex

A region of the brain involved in the planning of movements and the coordination of multiple muscles.

Corticospinal Tract Pathways

Pathways that include lateral corticospinal tract and ventral corticospinal tract, which differentiate based on fiber decussation.