Tendons are connective tissue, strong, fibrous cords that attach muscles to bones. They facilitate movement by transmitting muscle force to the skeletal system. The knee joint relies on several tendons to enable movement and maintain its stability. This article will explore the location of these key tendons within the knee.
Major Tendons of the Knee
The quadriceps tendon is located at the front of the thigh, just above the kneecap (patella). This large and strong tendon connects the quadriceps femoris muscle group, which consists of four muscles in the thigh, to the top of the patella. It works with the quadriceps muscles to straighten the knee, enabling activities such as standing, walking, running, and jumping.
Directly below the kneecap is the patellar tendon, which continues from the quadriceps tendon. This tendon connects the patella to the shinbone, or tibia, specifically to the tibial tuberosity. The patellar tendon is sometimes referred to as the patellar ligament because it forms a bone-to-bone connection, even though its primary function is to transmit muscle force.
At the back of the knee, three hamstring tendons connect the hamstring muscles to the lower leg bones. These include the semitendinosus, semimembranosus, and biceps femoris tendons. The semitendinosus and semimembranosus attach to the inside of the knee on the tibia. The biceps femoris attaches to the outside of the knee at the fibula.
A smaller, yet important, tendon in the knee is the popliteus tendon, found in a deeper, posterior, and lateral position at the back of the knee. This tendon originates from the lateral condyle of the femur and rotates the knee. It helps to “unlock” the knee from a fully extended position, allowing it to bend.
The gastrocnemius muscles (calf muscles) also have tendons that cross the back of the knee joint. These muscles are located in the posterior compartment of the lower leg, with their two heads originating from just above the knee on the femur. The tendons of the gastrocnemius muscles contribute to knee flexion and stability, particularly during movements like jumping, running, and walking.
Function and Differentiation of Knee Tendons
Tendons in the knee, like those throughout the body, serve to transmit mechanical forces from muscles to bones. This transmission of force allows for movement of the joint, such as bending and straightening the knee. Tendons also contribute to the overall stability of the knee joint.
It is important to differentiate tendons from ligaments, as both are types of fibrous connective tissues found in joints, but they serve different functions. Tendons consistently connect muscle to bone, enabling movement. In contrast, ligaments connect bones to other bones, primarily providing stability to joints and limiting excessive movement. For instance, the knee joint contains several ligaments that stabilize the bones.