Nathan P W, Smith M C, Deacon P
National Hospital for Nervous Diseases, Queen Square, London, UK.
Brain. 1990 Apr;113 ( Pt 2):303-24. doi: 10.1093/brain/113.2.303.
The course, location and relations of the corticospinal tracts within the spinal cord of man are demonstrated on the basis of cases with lesions above the spinal cord restricted to the corticospinal tracts, of motor neuron disease, and of anterolateral cordotomies; control cases were of normal spinal cords. The following features of the lateral corticospinal tract are emphasized in the cervical cord: (1) the large extent of the white matter of the cord covered by the tract, and the anterior extent of the tract, the border being anterior to the central canal; (2) in the lower cervical cord, the separation of fibres from the main mass of the tract, which reach the periphery of the cord in the anterolateral sector; (3) the presence in many cords of the ventral crossed bundle; and (4) the relationship of the denticulate ligament to the tracts in the cervical segments. The following features of the anterior corticospinal tracts are emphasized: (1) their location, caudal extent and asymmetry; and (2) the changes in location in relation to the median fissure as the tract descends and its relationship to other tracts of the anterior column. Three-quarters of spinal cords are asymmetric and in three-quarters of asymmetric cords the right side is the larger. The asymmetry is due to a greater number of corticospinal fibres crossing to the right side. As more fibres have crossed in the decussation, the anterior tract opposite the large lateral tract is smaller than the ipsilateral anterior tract: that accounts for the asymmetry of the two halves of the cord. The greater number of corticospinal fibres in the right side of the cord is unrelated to handedness, but correlates with the fact that in three-quarters of corticospinal decussations, the crossing from left to right occurs at a more cranial level than the opposite crossing. A group of short peripheral ascending fibres is described running along the sides of the median fissure in the thoracic cord.
基于脊髓以上病变局限于皮质脊髓束的病例、运动神经元病病例以及脊髓前外侧切断术病例，对人类脊髓内皮质脊髓束的走行、位置及关系进行了展示；对照病例为正常脊髓。在颈髓中，外侧皮质脊髓束有以下特征被着重指出：（1）该束所覆盖的脊髓白质范围广泛，且该束向前延伸，其边界位于中央管前方；（2）在颈髓下段，该束的纤维与主要束体分离，这些纤维在前外侧区到达脊髓周边；（3）许多脊髓中存在腹侧交叉束；（4）齿状韧带与颈段束的关系。前皮质脊髓束的以下特征被着重指出：（1）它们的位置、尾端范围及不对称性；（2）随着该束下行，其相对于正中裂位置的变化及其与前柱其他束的关系。四分之三的脊髓不对称，在四分之三不对称的脊髓中，右侧较大。这种不对称是由于更多的皮质脊髓纤维交叉到右侧。由于在交叉处有更多纤维交叉，与大的外侧束相对的前束比同侧前束小：这就解释了脊髓两半的不对称性。脊髓右侧皮质脊髓纤维数量较多与用手习惯无关，但与以下事实相关，即在四分之三的皮质脊髓交叉中，从左到右的交叉发生在比相反交叉更高的水平。描述了一组短的外周升支纤维沿胸髓正中裂两侧走行。
