Makino M, Mimatsu K, Saito H, Konishi N, Hashizume Y
Department of Orthopaedic Surgery, Tsushima Municipal Hospital, Aichi Medical University, Aichi, Japan.
Spine (Phila Pa 1976). 1996 May 1;21(9):1010-6. doi: 10.1097/00007632-199605010-00002.
Using human autopsy spinal cord specimens, morphologic measurements of myelinated nerve fibers were performed, focusing on the regions that include the main white matter conduction paths. The hemilateral spinal cord morphology was also measured, and its relation with the component myelinated nerve fibers determined.
To determine the relation between spinal cord transverse area in the normal lower cervical spine, the site most vulnerable to chronic compressive myelopathy, and myelinated nerve fibers.
Considerable interindividual variation normally is observed in the morphology of the spinal cord transverse area. The influence of this variation on the composition of the white matter myelinated nerve fibers is obscure.
The C7 segments from seven cadavers were resected, and from magnified photographs of paraffin-embedded specimens, the hemilateral spinal cord area and funicular area were measured. Nerve fiber morphology was measured using Epon-embedded specimens. Three regions that included the main conduction paths were sampled, and magnified photographs obtained. The nerve fiber transverse morphology was measured using the ellipse conversion method, and the myelinated nerve density and fiber area were determined.
Marked interindividual variations were found in both the hemilateral spinal cord transverse area and funicular area. A positive correlation was noted between the two, with the spinal cord transverse area large in the cases with a large funicular area. For fiber density and area, histograms were constructed that showed characteristic distribution patterns in each region. By dividing each region into two components (i.e., small- and large-diameter fibers), it was found that the interindividual variation in large-diameter fiber density was small, clarifying that the absolute number of large-diameter fibers compared to fiber density is more strongly dependent on the funicular area.
The absolute number of large-diameter myelinated fibers is smaller in cross-sections of thin as compared to those of thick spinal cord. When elucidating the pathophysiology of compressive myelopathy, it is necessary to study not only the circumstances surrounding the spinal cord, but this kind of factor intrinsic to the spinal cord itself.
使用人体尸检脊髓标本，对有髓神经纤维进行形态学测量，重点关注包含主要白质传导路径的区域。还测量了脊髓半侧形态，并确定其与有髓神经纤维成分的关系。
确定正常下颈椎最易发生慢性压迫性脊髓病的部位的脊髓横截面积与有髓神经纤维之间的关系。
通常在脊髓横截面积的形态上观察到个体间存在相当大的差异。这种差异对白质有髓神经纤维组成的影响尚不清楚。
切除七具尸体的C7节段，从石蜡包埋标本的放大照片中测量脊髓半侧面积和索状区域面积。使用环氧树脂包埋标本测量神经纤维形态。对包含主要传导路径的三个区域进行采样，并获取放大照片。使用椭圆转换法测量神经纤维横形态，并确定有髓神经密度和纤维面积。
在脊髓半侧横截面积和索状区域面积方面均发现明显的个体间差异。两者之间存在正相关，索状区域面积大的病例中脊髓横截面积也大。对于纤维密度和面积，构建的直方图显示了每个区域的特征分布模式。通过将每个区域分为两个部分（即小直径和大直径纤维），发现大直径纤维密度的个体间差异较小，这表明与纤维密度相比，大直径纤维的绝对数量更强烈地依赖于索状区域面积。
与厚脊髓的横截面相比，薄脊髓横截面中直径较大的有髓纤维的绝对数量较少。在阐明压迫性脊髓病的病理生理学过程时，不仅有必要研究脊髓周围的情况，还需要研究脊髓本身的这种内在因素。
