Motor Organization

Question 1

Lateral Pathways

Answer 1

Biased for Flexion

• Lateral corticospinal
• Rubrospinal
• Medullary (lateral) reticulospinal (bilateral)

Question 2

Medial Pathways

Answer 2

Biased for extension

• Pontine (medial) reticulospinal
• Lateral vestibulospinal
• Medial Vestibulospinal

Question 3

Amyotrophic Lateral Sclerosis

Answer 3

ALS, or Lou Gehrig’s Disease

progressive neuromuscular disease that destroys lower motor neurons and eventually parts of the corticospinal/corticobulbar tracts.

Symptoms:
weakness and difficulty speaking and/or swallowing.
Death due to respiratory failure usually occurs 3 - 5 years after diagnosis.

Question 4

Anterior Spinal Artery Syndrome

Answer 4

infarction is a common cause.

Lesions of:
– anterior horn cells
– lateral and anterior corticospinal tract
– anterolateral system

Symptoms:
– spastic paraparesis
– bilateral loss of pain and temperature below lesion
– retention of urine
– sexual functions impaired

Question 5

Syringomyelia

Answer 5

longitudinal cyst that develops along the central canal. The cyst usually expands ventrally and compresses the ventral horns and the ventral white commissure.

Symptoms:
Segmental muscular atrophy
Loss of pain and temperature senses