Tendon vs Ligament
Tendons and ligaments are vital parts of the skeletal and muscular systems of animals, especially in vertebrates. Without tendons and ligaments, neither the bones nor muscles would have been connected. That means, muscles are attached to bones and bones are attached to each other through the connections of tendons and ligaments. However, the two structures have not been well understood to observe the differences between each other. Therefore, it would be important to describe both tendons and ligaments with some emphasis on the difference between them.
Tendon is a type of connective tissue that connects muscles with bones. The structure of a tendon is solid and tough with the parallel arrangement of collagen fibres that are closely packed. As a whole, a tendon usually consists 30% of water, but apart from that collagen is the predominant presence in the tissue. In other words, the dry weight of a tendon comprises about more than 85% of collagen. In addition, small amounts of elastin, proteoglycans, and inorganic compounds are present in a tendon.Collagens are mainly composed of Type I collagen (98%) and other types are present in only very small amounts. The collagen fibres are contained in the specialized cells called fibroblasts in the proteoglycan medium.
One of the most important features of a tendon is its length, which varies from tendon to tendon and person to person. Tendons have a considerable blood supply compared to many other collagenous tissues of the body, with vessels, insertions, and from surrounding tissues. The main function of a tendon is to transmit the force from a muscle contraction into the bone. However, the elastic properties of the tendons have been studied and proven the importance for the world, as the elasticity allows the tendon to store energy and use it passively through modulation while locomotion.
Ligament is a tough and solid type of fibrous tissue that connects bones with other bones. In fact, a ligament connects two bones at the joint but not at the middle. Depending on the location or the bone in the skeletal system, some bones are allowed to move freely, but some are restricted; all these are due to the way that the ligaments have been arranged at the joints of bones. The composition of a ligament is about 80% of collagen and about 5% of proteoglycans in the dry weight. The presence of elastin is low in ligaments and the fibres are contained in fibroblasts in the proteoglycan medium. The fibroblasts have a parallel arrangement, and the thickness of a ligament is not much high as tendons. The blood supply is poor to the ligaments, but fibroblasts get the supply through insertion of micro vessels to have enough nutrients for the matrix synthesis and repair. The presence of elastin in ligaments makes sure that the bones have a small suspension over forces created upon those. However, the elasticity varies from ligament to ligament and person to person.
What is the difference between Tendon and Ligament?
• Both are connective tissues but tendon connects muscles with bones while ligaments connect bones with bones.
• Tendon connects the end of a muscle to any place of the bone, whereas ligaments always connect bones at their joints.
• There is only one tendon for a particular muscle at one end while there are few ligaments connecting two bones at a joint.
• Tendons have more collagens than ligaments do.
• Ligaments have more proteoglycans than tendons do.
• Tendons have a higher blood supply compared to ligaments.