Distribution of Capillaries in Relation to Oxidative Metabolism of Skeletal Muscle Fibres

Abstract

THE anatomical arrangement of the blood-vessels in skeletal muscle was examined in detail by Ranvier¹ and by Spalteholz². The capillaries were found to form a columnar network with longitudinal branches running parallel to the muscle fibres and transverse branches forming segments of rings around the fibres. Ranvier noted that the red muscles of rabbit had a higher density of capillaries than the pale ones. Investigations by Stoel³, and Duyff and Bouman⁴, revealed a difference in the number of capillaries in various muscles of the same animal. Subsequent studies of capillaries in animals under normal and physiologically altered states, by investigators such as Krogh⁵, Lindgren⁶, Petrén et al.⁷, showed only a change in the total number of capillaries. Bullard⁸ demonstrated that pale muscles consisted of a variable mixture of fibres of different darkness and size. Recently, Dubowitz and Pearse⁹ have shown histochemically that these fibres of a pale muscle have different intensities of cytochrome oxidase activity.