Spinal Motor Organization & Brainstem Supraspinal Paths

These flashcards cover the key vocabulary related to spinal motor organization and brainstem pathways, crucial for understanding motor functions and clinical implications.

Spinal Motor Neurons

Neurons that control muscle movements; organized with medial cell bodies for proximal muscles and lateral cell bodies for distal muscles.

Corticospinal Tract (CST)

The pathway that carries signals from the cerebral cortex to the spinal cord, functioning as the 'elevator system' for voluntary motor control.

Propriospinal Neurons

Neurons that link multiple spinal cord levels to coordinate motor actions, divided into long, intermediate, and short propriospinal neurons.

Long Propriospinal Neurons

Neurons that ascend or descend within the anterior fasciculus proprius and influence medial motor neurons, controlling trunk and axial muscles.

Vestibular Nuclear Complex

A group of four nuclei in the brainstem that significantly influence spinal motor activity and maintain balance and equilibrium.

Decerebrate Posturing

A condition where a comatose patient exhibits extension of both upper and lower limbs due to brainstem damage affecting motor control.

Medullary Reticular Formation

Part of the brainstem that, through lateral reticulospinal fibers, facilitates flexor movements while inhibiting extensors.

Red Nuclei

Located in the midbrain, these nuclei are involved in facilitating flexor movements of contralateral upper limbs.

Supraspinal Paths

Descending pathways from higher brain centers to the spinal cord, categorized into ventromedial, lateral, and cortical groups.

Ventromedial Pathway

Part of the spinal cord's anterior funiculus, influencing bilateral axial muscle movements and posture.

Decorticate Posturing

A condition indicating damage above the red nucleus, characterized by upper limb flexion and lower limb extension.

Capesular Lesion Recovery

Recovery mechanisms post-brain injury that involve different influence levels on upper body and distal limb movements.

Lateral Vestibulospinal tract

A descending pathway that primarily influences extensor muscles of the ipsilateral limbs.

Medial Vestibulospinal tract

A tract that affects bilateral muscles in the head, neck, trunk, and proximal limbs for balance and stability.

Corticoreticular fibers

Fibers that influence reticular formation from the cortex, affecting motor control.

Intrinsic Hand Muscles

Muscles specifically controlled by the corticospinal tract; critical for fine motor tasks.

CST Influence on Distal Muscles

The corticospinal tract uniquely influences the most distal muscles, including the fingers, under direct cortical control.