Mechanical tests were performed at physiological loads and loading rates to determine the material properties of ligamentous tissues. One of the difficulties in determining the material properties lies in measuring the cross-sectional area of the tissue.

An experimental method was developed utilizing a highspeed computerized image analysis system to measure the cross-sectional area of ligament tissue. The method consists of Rash-freezing ligament tissue in liquid nitrogen and then sectioning the tissue at discrete locations along its length. A non-destructive casting technique was also developed to determine the cross-sectional area of ligament specimens prior to sectioning. Casts of ground steel shaft standards made to verify the precision of the casting technique were accurate to within 0.5% of the diameter of the standards. Images of individual cross-sections for both ligament and cast sections were acquired using a high resolution video camera system. The computer counted the pixels for each section, determining the cross-sectional area of the tissue. Area measurements of precision standards were repeatable to within 0.4%. A comparison study was performed for an average area value of ligament cross-sections and an average area value for cast cross-sections. The variations between these are within 8.3%. A section by section comparison of ligament versus casting was also performed. In most cases, the variations between ligament section and cast section was less than 10%. The casting technique utilizing the image analysis system is an accurate, non-destructive way to determine the cross-sectional area of ligament tissue. It does not assume a shape for the area and can detect concavities on the surface of the tissue.