Variations in the amount of calcified tissue at the attachments of the quadriceps tendon and patellar ligament in man.

Differences are reported in the total calcified tissue/bone marrow ratios and in the total thickness of cortical calcified tissue (lamellar bone and calcified fibrocartilage) between the attachment sites of the quadriceps tendon and the patellar ligament in man. The greatest amount of calcified tissue is at the insertion of the tendon and this is correlated with the larger force that the tendon transmits. It is concluded that differences in maximum force alone can produce a greater density of calcified tissue at ligament or tendon attachments. The similar amounts of calcified tissue at each end of the patellar ligament reflect the identical force that each attachment transmits. At the insertion of the quadriceps tendon and the 'origin' of the patellar ligament, there was more calcified tissue beneath the superficial than the deep parts of the attachment. This suggest that more force is transmitted through some parts of an attachment zone than others.