Mannion A F, Dumas G A, Cooper R G, Espinosa F J, Faris M W, Stevenson J M
Department of Anatomy, University of Bristol, UK.
J Anat. 1997 May;190 ( Pt 4)(Pt 4):505-13. doi: 10.1046/j.1469-7580.1997.19040505.x.
This study sought to investigate the normal muscle fibre size and type distribution of the human erector spinae, both in thoracic and lumbar regions, in a group of 31 young healthy male (n = 17) and female (n = 14) volunteers. Two percutaneous muscle biopsy samples were obtained under local anaesthesia, from the belly of the left erector spinae, at the levels of the 10th thoracic and 3rd lumbar vertebrae. Samples were prepared for routine histochemistry for the identification of fibre types. Fibre size (cross-sectional area (CSA) and narrow diameter (ND)) was quantified using computerised image analysis. The mean CSA/ND for each fibre type was greater in the thoracic than the lumbar region, but there was no difference between the 2 regions either for percentage type I (i.e. percentage distribution by number), percentage type I area (i.e. relative area of the muscle occupied by type I fibres) or the ratio describing the size of the type I fibre relative to that of the type II. Men had larger fibres than women, for each fibre type and at both sampling sites. In the men, each fibre type was of a similar mean size, whereas in the women the type I fibres were considerably larger than both the type IIA and type IIB fibres, with no difference between the latter two. In both regions of the erector spinae there was no difference between men and women for the proportion (%) of a given fibre type, but the percentage type I fibre area was significantly higher in the women. The erector spinae display muscle fibre characteristics which are clearly very different from those of other skeletal muscles, and which, with their predominance of relatively large type I (slow twitch) fibres, befit their function as postural muscles. Differences between thoracic and lumbar fascicles of the muscle, and between the muscles of men and women, may reflect adaptive responses to differences in function. In assessing the degree of any pathological change in the muscle of patients with low back pain, it seems clear that (1) sex cannot be disregarded and (2) 'atrophied' (using the criteria from other muscles) type II fibres are not necessarily abnormal for the erector spinae, particularly in women.
本研究旨在调查31名年轻健康男性（n = 17）和女性（n = 14）志愿者的胸段和腰段竖脊肌的正常肌纤维大小及类型分布。在局部麻醉下，从第10胸椎和第3腰椎水平的左侧竖脊肌肌腹获取两份经皮肌肉活检样本。样本经常规组织化学处理以识别纤维类型。使用计算机图像分析对纤维大小（横截面积（CSA）和窄径（ND））进行量化。每种纤维类型的平均CSA/ND在胸段大于腰段，但在I型纤维百分比（即按数量计算的百分比分布）、I型纤维面积百分比（即I型纤维所占肌肉的相对面积）或描述I型纤维与II型纤维大小之比方面，两个区域之间没有差异。对于每种纤维类型以及在两个采样部位，男性的纤维都比女性的大。在男性中，每种纤维类型的平均大小相似，而在女性中，I型纤维明显大于IIA型和IIB型纤维，后两者之间没有差异。在竖脊肌的两个区域，给定纤维类型的比例（%）在男性和女性之间没有差异，但女性的I型纤维面积百分比显著更高。竖脊肌显示出的肌纤维特征明显不同于其他骨骼肌，并且由于其相对较大的I型（慢肌纤维）纤维占优势，适合其作为姿势肌的功能。该肌肉胸段和腰段肌束之间以及男性和女性肌肉之间的差异可能反映了对功能差异的适应性反应。在评估腰痛患者肌肉的任何病理变化程度时，显然（1）不能忽视性别因素，（2）对于竖脊肌而言，（按照其他肌肉的标准）“萎缩”的II型纤维不一定异常，尤其是在女性中。
