Morphological central nervous system abnormality Abnormal pyramidal tract morphology HP:0012445 UMLS:C4021761 Pyramidal tract disease 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. Morphological abnormality of the pyramidal tract The pyramidal tracts comprise both the corticospinal and corticobulbar tracts. HP:0002062 Abnormality of the pyramidal tracts UMLS:C4020859