The knee joint is responsible for many movements like bending and extending the leg. The muscles of the knee joint are the actor of all these knee motions. It is a hinge joint, meaning it only bends.
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Muscles of the knee joint
there are 3 groups of the muscles of the knee joint that allow movements of the knee joint:
1-Popliteus muscle
The popliteus muscle is the tiny muscle located behind your knee. Some people refer to the muscle as the "sleeper" because it rarely causes pain. If you feel pain in your knee, however, and then press on a point about one finger-width above your knee cap, you may feel pain from an injury to this muscle.
2-Quadriceps muscles
The quadriceps involve four muscles (vastus lateralis,rectus femoris, vastus medialis, and vastus intermedius) in the thigh that run from the hip to the knee.
Together they make up about one-quarter of the muscle mass in your leg. The quadriceps are large and flat muscles that cover much of the front of your thigh. They provide most of your power when you walk or run or do any other activity requiring you to move your legs quickly back and forth over short distances.
Rectus femoris
The rectus femoris (tegmina superficialis) is the most superficial of three muscles in the quadriceps group. It originates from the anterior inferior iliac spine and inserts into the patella via a tendon passing through its tendon sheath. The rectus femoris is responsible for flexing the knee joint, and also plays an important role in extending it.
The muscle can be palpated as a distinctly rounded bulge along its entire length when viewed from behind.
This muscle and two other muscles (vast intermedius and vastus lateralis)
are responsible for knee extension.
The vastus lateralis
The vastus lateralis is considered the largest quadriceps muscle in your body.
It originates from the greater trochanter of the femur and inserts into the tibia via a long tendon that passes over the top of the knee joint.
The vastus lateralis is responsible for flexing and extending at both of these joints as well as hip abduction and adduction.
The vastus medialis
The vastus medialis is a quadriceps muscle located in the upper, inner part of the thigh. It originates on the femur, or thigh bone and inserts into the tibia or shinbone. This muscle helps to straighten the knee joint and assists with walking and running.
The vastus medialis muscle originates from within the tendon of insertion of rectus femoris (also known as ‘vastus intermedius’) at approximately 2cm proximal to its insertion on the patella (knee cap). It also receives some fibers from the sartorius muscle.
The vastus intermedius
The vastus intermedius is one of the quadriceps muscles, and it runs from the lower, outer portion of the femur to the upper, inner portion of the tibia.
It lies on top of 3 other muscles that make up the quadriceps group (the rectus femoris and two vasti muscles) at an oblique angle.
The vastus intermedius originates from a large flat area on the front part of your upper femur bone called its anterior inferior iliac spine; this muscle shares its origins with all four parts of your quadriceps muscles.
The vastus intermedius is located in the upper third of the quadriceps muscle group. It acts to extend and rotate the knee joint. It also plays an important role in the stabilization of the patella during knee extension.
3-Hamstring muscles
The leg consists of two major groups: the anterior compartment, which contains the tibialis anterior muscle, and the posterior compartment, which includes the hamstring group.
The hamstrings play an essential role in walking and running by controlling hip extension (straightening) and knee flexion (bending) .
Additionally, people who participate in sports such as soccer may injure their hamstrings while kicking or sprinting. This can lead to pain along the outer side of your thighs—especially when you try to walk upstairs.
The hamstrings is group of three muscles:femoris,biceps, semitendinosus, and semimembranosus.All of them are located at the back of your thighs
The hamstrings assist the extension of the hip and bending the knee.
Overstretching or torn of one or more of these muscles cause hamstring strains.
When this happens, you have a hamstring strain. If it is mild, you can treat it with rest, ice and compression until the pain goes away. If it is severe, you may need surgery to repair a muscle tear or rupture.
Biceps femoris
The biceps femoris is located in the posterior compartment of the leg and has two heads, a long head, and a short head. The long head originates on the ischial tuberosity and inserts into the lateral condyle of the tibia.
It crosses both joints in the knee with its tendon intertwined with that of semitendinosus; it also sends an aponeurosis to the joint capsule.
The short head originates on the inferior ramus of the pubis (inferior pubic ramus) and inserts into the medial surface of the fibula below the attachment point for the long head.
Semitendinosus
Semitendinosus is one of the muscles of the thigh which originates from the front of the greater trochanter, runs down and back, and ends in the tendinous fascia covering the medial surface of the knee joint (popliteal fossa).
The semitendinosus is inserted into an area on the tibia just behind and below the head to form part of its posterior surface. This insertion can be felt through several layers of soft tissues as a lumpy swelling--the semimembranosus tuberosity.
Semimembranosus
The semimembranosus helps in flexing the thigh and straightening the knee as it's a very strong muscle.
Fibers of semimembranosus muscle begin at the back of your lower pelvis, run downwards to the upper part of your shinbone, or tibia.
It then attaches to your calf muscles (muscles of lower leg)just below your kneecap.
The semimembranosus originates from its tendon on either side of the popliteal fossa which is a depression behind and above our knees.
Summary
The muscles of the knee joint are quite complex. In general, they consist of a large number of fibers that connect to different bones and joints to coordinate knee movement.
By.Dr.Fatma Ragab
Read more: knee Support
Read more: knee Support
Read more: knee Support
Read more: knee Support
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