Terao S, Sobue G, Hashizume Y, Shimada N, Mitsuma T
Fourth Department of Internal Medicine, Aichi Medical University, Japan.
Acta Neuropathol. 1994;88(2):137-42. doi: 10.1007/BF00294506.
A quantitative analysis was made of the myelinated fibers in the lateral corticospinal tract (LCST) at the levels of the 6th cervical, 7th thoracic and 4th lumbar spinal segments in 20 patients between 19 and 90 years old, and who died of non-neurological diseases. The diameter frequency histograms of myelinated fibers of LCST showed a bimodal pattern with a sharp peak of the small myelinated fibers and broad slope of the large myelinated fibers. The ratio of small fiber to large fiber densities was significantly higher in the 6th cervical (P < 0.05) and 4th lumbar segments (P < 0.01) than in the 7th thoracic segments. The density of small myelinated fibers was significantly lowered with advancing age (P < 0.05-0.001), while that of large myelinated fibers was not significantly decreased in the aged patients, although it showed a slight age-dependent declining tendency. Age-dependent decline of small fiber density was more prominent in the cervical and lumbar segments. Retraction of the axon-collaterals from large-diameter myelinated fibers, which are abundant in the cervical and lumbar segments, may contribute to the age-related diminution of the small myelinated fibers in the LCST.
对20例年龄在19至90岁之间、死于非神经系统疾病的患者，在第6颈椎、第7胸椎和第4腰椎脊髓节段水平的皮质脊髓侧束（LCST）中的有髓纤维进行了定量分析。LCST有髓纤维的直径频率直方图呈双峰模式，小直径有髓纤维有一个尖峰，大直径有髓纤维有一个宽斜率。第6颈椎节段（P < 0.05）和第4腰椎节段（P < 0.01）中小纤维与大纤维密度之比显著高于第7胸椎节段。小直径有髓纤维的密度随年龄增长显著降低（P < 0.05 - 0.001），而老年患者中大直径有髓纤维的密度虽有轻微的年龄依赖性下降趋势，但无显著降低。小纤维密度的年龄依赖性下降在颈椎和腰椎节段更为明显。来自大直径有髓纤维的轴突侧支回缩，在颈椎和腰椎节段中大量存在，可能导致LCST中小有髓纤维的年龄相关减少。
