Fukunaga T, Roy R R, Shellock F G, Hodgson J A, Day M K, Lee P L, Kwong-Fu H, Edgerton V R
Department of Sports Sciences, University of Tokyo, Japan.
J Orthop Res. 1992 Nov;10(6):928-34. doi: 10.1002/jor.1100100623.
Magnetic resonance imaging techniques were used to determine the physiological cross-sectional areas (PCSAs) of the major muscles or muscle groups of the lower leg. For 12 healthy subjects, the boundaries of each muscle or muscle group were digitized from images taken at 1-cm intervals along the length of the leg. Muscle volumes were calculated from the summation of each anatomical CSA (ACSA) and the distance between each section. Muscle length was determined as the distance between the most proximal and distal images in which the muscle was visible. The PCSA of each muscle was calculated as muscle volume times the cosine of the angle of fiber pinnation divided by fiber length, where published fiber length:muscle length ratios were used to estimate fiber lengths. The mean volumes of the major plantarflexors were 489, 245, and 140 cm3 for the soleus and medial (MG) and lateral (LG) heads of the gastrocnemius. The mean PCSA of the soleus was 230 cm2, about three and eight times larger than the MG (68 cm2) and LG (28 cm2), respectively. These PCSA values were eight (soleus), four (MG), and three (LG) times larger than their respective maximum ACSA. The major dorsiflexor, the tibialis anterior (TA), had a muscle volume of 143 cm2, a PCSA of 19 cm2, and an ACSA of 9 cm2. With the exception of the soleus, the mean fiber length of all subjects was closely related to muscle volume across muscles. The soleus fibers were unusually short relative to the muscle volume, thus potentiating its force potential.(ABSTRACT TRUNCATED AT 250 WORDS)
采用磁共振成像技术测定小腿主要肌肉或肌肉群的生理横截面积（PCSA）。对12名健康受试者，沿着小腿长度以1厘米间隔拍摄的图像中，将每块肌肉或肌肉群的边界进行数字化处理。肌肉体积通过各解剖横截面积（ACSA）之和与各截面之间的距离计算得出。肌肉长度确定为肌肉可见的最近端和最远端图像之间的距离。每块肌肉的PCSA计算为肌肉体积乘以羽状肌纤维角度的余弦值除以纤维长度，其中已发表的纤维长度与肌肉长度的比值用于估计纤维长度。比目鱼肌以及腓肠肌内侧头（MG）和外侧头（LG）的主要跖屈肌平均体积分别为489、245和140立方厘米。比目鱼肌的平均PCSA为230平方厘米，分别约为MG（68平方厘米）和LG（28平方厘米）的三倍和八倍。这些PCSA值分别是其各自最大ACSA的八倍（比目鱼肌）、四倍（MG）和三倍（LG）。主要背屈肌胫骨前肌（TA）的肌肉体积为143平方厘米，PCSA为19平方厘米，ACSA为9平方厘米。除比目鱼肌外，所有受试者的平均纤维长度与各肌肉的肌肉体积密切相关。比目鱼肌的纤维相对于肌肉体积异常短，因此增强了其力量潜力。（摘要截取自250字）
