Connective tissues are found throughout the body, holding together the skeletal and muscular systems as well as the organ systems and membranes. These tissues consist of protein fibers and have elastic properties depending on their content of a protein called elastin. Collagen is also a main component of connective tissues, giving them strength and a fibrous quality.
Two types of connective tissue with similar, but different, functions are ligaments and tendons. Both tissues cross joints, but each has its own purpose and distinctive characteristics.
Differences in Tendon and Ligament Structure
Though tendons and ligaments are both regularly arranged dense connective tissues made of layered type I collagen fibrils, fibroblasts, and proteoglycan matrix, they have different proportions of these materials and varying degrees of organization.
Compared to ligaments, tendons are more fibrous, but they are also likened to a spring as opposed to being tough, fibrous bands. These differences are accompanied by the following relative characteristics in their composition:
- Tendons have more organized collagen fibrils
- Ligaments contain more proteoglycan matrix
Differences in Blood Supply and Origin
Another difference between these two connective tissues is their insertion points into the skeletal structure. Though both ligaments and tendons attach to bone, ligaments do not attach to muscle. This difference in connections also causes another difference between the two tissues – blood supply.
Tendons can receive a blood supply from the surrounding tissues where it attaches to the muscle. The ligaments are limited to a lesser supply from a small web of vessels in the synovial membranes of the joints they cross. However, neither tissue heals well nor are they well vascularized. Both can require surgery to repair injuries.
Differences in Function
Tendons act as a pulley, carrying tensile forces from the muscle to the bone, using the bone as a solid support to move the muscle. In contrast to the pulley mechanism formed by tendons, ligaments limit joint movement and hold the bones together. At some joints, ligaments partially encapsulate the bone-to-bone connection. The movement induced by tendons is partially directed by the ligament holding together the joint and limiting the direction and degree of movement.
For more about ligaments, see Structure and Function of Ligaments.
For more about tendons, see Structure and Function of Tendons.
Additional resources:
Scanlon and Sanders. Essentials of Anatomy and Physiology, 4th edition. 2003.
Toy et al. Arterial supply to the human anterior cruciate ligament. Journal of Athletic Training, 30(2), 1995.
University of Michigan College of Engineering. “BME/ME 456 Biomechanics: Structure and function of ligaments and tendons”. Engin.umich.edu Accessed April 20, 2010.
Alicia Mae Prater - Alicia received her doctorate in Experimental Pathology in 2007. She has been a freelance writer and scientific editor since 2008.
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