abnormal nervous system tract morphology abnormal anterior corticospinal tract morphology abnormal anterior pyramidal fasciculus morphology abnormal Turck bundle morphology any structural anomaly of the small bundle of corticospinal motor fibers that do not cross the midline at the pyramidal decussation and descend into the anterior funiculus of the spinal cord; the anterior corticospinal tract controls central axial and girdle muscles abnormal ventral corticospinal tract morphology abnormal anterior cerebrospinal fasciculus morphology MPheno.ontology abnormal direct pyramidal tract morphology abnormal medial corticospinal tract morphology MP:0009682 abnormal anterior pyramidal tract morphology abnormal Turck column morphology