Any structural abnormality of the pyramidal tract, whose chief element, the corticospinal tract, is the only direct connection between the brain and the spinal cord. In addition to the corticospinal tract, the pyramidal system includes the corticobulbar, corticomesencephalic, and corticopontine tracts.
Abnormal spinal cord morphology +
Abnormal subarachnoid space morphology +
Abnormality of neuronal migration +
Alzheimer disease
Aplasia/Hypoplasia involving the central nervous system +
Atrophy/Degeneration affecting the central nervous system +