Fine structure of the human skeletal muscle capillary. A morphometric analysis.

Capillary dimensions in muscle biopsies from human musculus quadriceps femoris, sectioned at right angle to the muscle fibers, were analysed with a computerized planimetric technique giving distributions of dimensional parameters with statistics. Without corrections for estimated preparative shrinkage mean maximal diameter of lumen was 3.82 +/- 0.82 microns (5.31 +/- 1.14 micron shrinkage corrected), mean second maximal diameter, at right angle to maximal, 2.61 +/- 0.72 microns (3.62 +/- 1.00 microns corr.) and mean endothelial thickness in nuclear free sections 0.35 micron (0.49 micron corr.) micron. Using a capillarity of 360/mm2 for the human m. quadriceps femoris, the total surface area of skeletal muscle capillaries was calculated to be 5.50 X 10(3) cm2/100g and the total volume of the capillary network in the muscle to be 0.48 cm3/100g.