MYOFIBROUS ORGANIZATION OF THE TENSOR FASCIAE LATAE MUSCLE

The shape and myofibrous organization of the tensor fasciae latae muscle was investigated quantitatively to elucidate functional characteristics of the muscular morphology. The present data were compared with data accumulated in our laboratory. Right tensor fasciae latae muscles were obtained from 27 cadavers for dissecting practice (18 males, 9 females, mean age 68.6 yrs) . After the length, width and thickness of the muscle were measured, H.E. stained preparations were made for measurement of the muscle fiber. Results : 1. The muscle masses and volumes were larger in male than in female. Trends of change due to aging were observed. These trends were remarkable in both males and females older than 60. Cross sectional areas of the muscle belly in the oldest group were also very small. 2. The mean number of the muscle fibers in a unit area (1 mm²) was greater in females (1176) than in males (1012) . These values were smaller than those of the psoas major muscle, and similar to those of the iliacus muscle, but were larger than those of the quadratus lumborum muscle. 3. The mean numbers of total muscle fibers per muscle were 188112 in males and 170531 in females. Trends of change due to aging were observed in males. The trend in males was similar to those of the quadratus lumborum and iliacus muscles, but less than that of the psoas major muscle. The trend in females was similar to that of the psoas major muscle, but less than that of the quadratus lumborum muscle. 4. The mean cross sectional areas of the muscle fibers were 802 μm² in males and 632 μm² in females. Derease of thickness due to aging was observed in males. These values were similar to those of the psoas major muscle in both sexes, but smaller than those of the quadratus lumborum and iliacus muscles. 5. The mean density of muscle fiber was larger in males (74.5 %) than in females (65.8 %) . These values were similar to those of the psoas major and quadratus lumborum muscles in both males and females.