释义 |
DictionarySeedecussationpyramidal decussation
py·ram·i·dal de·cus·sa·tion (pir-am'i-dăl dē'kŭs-ā'shŭn) The intercrossing of the bundles of the pyramidal tracts at the lower border region of the medulla oblongata. Synonym(s): decussatio pyramidum [TA] , motor decussation. pyramidal decussationThe crossing of 90% of the axons of the corticospinal tracts (the pyramidal tracts) in the ventral region of the caudal hindbrain. On the contralateral side, the crossed axons interdigitate with 10% of the corticospinal axons that have not crossed, and the full complement of axons continues into the spinal cord in the lateral funiculus. Synonym: decussation of the pyramidsSee also: decussation |