Contents
- 1 What muscles cause the knee to extend?
- 2 What muscle is responsible for extension of the leg at the knee joint?
- 3 What are the knee extensors?
- 4 How does the knee extend?
- 5 What are the muscles involved in knee flexion and extension?
- 6 How are hamstrings and quadriceps related to the knee?
- 7 What causes tightness in the muscles around the knee?
What muscles cause the knee to extend?
Extension: Produced by the sartorius and quadriceps femoris group of muscles. Flexion: Produced by the biceps femoris, semitendinosus, and semimembranosus muscles. The popliteus muscle facilitates this movement by unlocking the fully extended knee joint.
What muscle is responsible for extension of the leg at the knee joint?
Quadriceps Femoris Group
| Muscle | Actions |
|---|---|
| Rectus femoris | Extension of the leg at the knee joint; flexion of the hip |
| Vastus lateralis | Extension of the leg at the knee joint |
| Vastus intermedius | Extension of the leg at the knee joint |
| Vastus medialis | Extension of the leg at the knee joint |
Which muscles flex and extend the knee joint?
The semi-tendinosis, semi-membranous and biceps femoris muscles (hamstrings) flex the knee and extend the thigh. Because the muscles used reproduce a combined maximal excursion at one joint (eg extension of the thigh) they will limit movement at the other joint to less than maximal.
What are the knee extensors?
The extensor mechanism of the knee consists of the quadriceps muscle group, quadriceps tendon, patella, patellar retinaculum, patellar ligament, and adjacent soft tissues.
How does the knee extend?
When you straighten your leg, the quadricep muscles pull on the quadricep tendon, this pulls the kneecap to make the knee extend. When you bend it, the hamstring muscles contract and pull the tibia backwards, causing the knee to flex.
How much can the knee extend?
From a flexed position of around 135 degrees the knee extends or straightens to 0 degrees. Fluid-filled sacs called bursae serve as gliding surfaces for the tendons to reduce the force of friction as tendons move.
What are the muscles involved in knee flexion and extension?
For knee flexion the muscles involved are Sartorius, Gracilis, Semimembranosus, Semitendinosus, Bicep Fermoris Long Head & Short Head, Popliteus, Gastrocnemius and Plantaris. For knee extension the muscles involved are quadriceps. They are made of four individual muscles; rectus femoris, vastus intermedius, vastus lateralis, and vastus medialis.
The hamstrings and quadriceps work together, one contracting (agonist) while the other relaxes (antagonist) to allow the knee to bend and straighten. There are also other muscles that work with the quads and the hamstrings, that are just as important to help protect the knee, most notably the glutes and calf muscles.
What are the four extensors of the knee?
The four Extensors of the knee, namely rectus femoris, vastus lateralis, vastus medialis, vastus intermedius are collectively known as the Quadriceps femoris muscle. The Quadriceps tendon inserts into the proximal aspect of patella and then continues distally past the patella as the patellar tendon.
What causes tightness in the muscles around the knee?
Tightness or weakness in the quadriceps, hamstrings and other muscles around the knee are often part of the cause of knee pain. If there is muscle imbalance, it changes the way the forces go through the knee, and puts extra pressure on certain areas, leading to knee pain. How To Strengthen The Knee Muscles