Understanding the Difference Between a Tendon and a Ligament

Tendons and ligaments are robust connective tissues that support the musculoskeletal structure and allow proper body movements. Both tendons and ligaments are made up mostly of the structural protein called collagen and a small amount of elastin. They also contain water and essential proteins that help maintain connective tissue integrity, provide bone and muscle lubrication, and ensure proper anatomical spacing. However, these two forms of connective tissue are found in different locations and provide distinct functions.

A tendon connects muscle to bone, and its primary function is to transfer the force of a muscle contraction to the bone, thereby allowing limb and joint movement in a unilateral direction. During a muscle contraction, the muscle pulls on the tendon it is attached to, and the tendon pulls on the bone, thus leading to joint movement. For a tendon to function properly, it must be able to withstand strong forces without becoming overextended, as this can lead to an injury. Ligaments are somewhat different in that they help skeletal structures stay in place.

More specifically, a ligament attaches bone to bone, with its main function involving the prevention of abnormal or excessive joint movements. Like tendons, a healthy ligament resists intense forces, but in contrast to tendons, ligaments allow a wider range of motion for the associated joint. Furthermore, a ligament confers flexibility through its ability to stretch and retract during joint movement.

Understanding the difference between a tendon and a ligament helps demonstrate the distinctions between a sprain and strain, as a strain typically refers to an injured tendon or muscle it is connected to, while a sprain refers to an injured ligament. Individuals who experience a sprain generally report feeling an abrupt onset of sharp pain, as well as hearing or feeling a pop when the injury occurred. They also tend to struggle to put weight on the joint following this type of injury. A common area for sprain is the ankle. On the other hand, when a strain occurs, common symptoms that are reported include feeling a sharp pain during a specific movement and pain that worsens when moving the associated muscle. A strain may also lead to muscle tightening or spasms. A common area for a strain is the hamstring muscle.

If a sprain or a strain is suspected and the accompanying pain is making it difficult to move normally or engage in regular daily activities, it is important to speak with a healthcare provider, such as a physiotherapist. Physiotherapy is frequently recommended following a moderate to serious sprain or strain due to the demonstrated benefits of this pain management approach. A highly skilled physiotherapist is knowledgeable at providing education about strength-training techniques and therapeutic movements that promote healing and a restored range of motion.

The physiotherapy team at Emerald Hills Physio & Sports Clinic offers tailored treatment plans that help accelerate the recovery process and reduce the risk of long-term complications. The guided techniques and exercises can also be performed at home as instructed by a physiotherapist to help prevent future injuries.

Untreated tendon or ligament injuries can lead to major issues, such as joint instability, chronic pain, limited mobility, and even musculoskeletal disorders (e.g., osteoarthritis). However, knowing the difference between the purposes of a tendon and a ligament can help identify when there is a problem and indicate when it is time to speak with a health provider who can help.

References

Asahara H, Inui M, Lotz MK. Tendons and ligaments: Connecting developmental biology to musculoskeletal disease pathogenesis. J Bone Miner Res. 2017;32(9):1773-1782.
Rumian AP, Wallace AL, Birch HL. Tendons and ligaments are anatomically distinct but overlap in molecular and morphological features — A comparative study in an ovine model. J Ortho Res. 2007;25:458-464.
Souza Jd, Gottfried C. Muscle injury: Review of experimental models. J Electromyogr Kinesiol. 2013;23(6):1253-1260.
Green B, McClelland JA, Semciw AI, et al. The assessment, management, and prevention of calf muscle strain injuries: A qualitative study of the practices and perspectives of 20 expert sports clinicians. Sports Med Open. 2022;8(1):10.
de Ruvo R, Russo G, Lena F, et al. The effect of manual therapy plus exercise in patients with lateral ankle sprains: A critically appraised topic with a meta-analysis. J Clin Med. 2022;11(16):4925.

Delco ML, Kennedy JG, Bonassar LJ, Fortier LA. Post-traumatic osteoarthritis of the ankle: A distinct clinical entity requiring new research approaches. J Orthop Res. 2016;35(3):440-453.