Vastus medialis | |
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![]() Muscles of lower extremity (Rectus Femoris has been removed) | |
Details | |
Origin | Medial side of femur |
Insertion | Quadriceps tendon |
Artery | Femoral artery |
Nerve | Femoral nerve |
Actions | Extends knee |
Identifiers | |
Latin | musculus vastus medialis or musculus vastus internus |
TA98 | A04.7.02.023 |
TA2 | 2620 |
FMA | 22432 |
Anatomical terms of muscle |
The vastus medialis (vastus internus or teardrop muscle) is an extensor muscle located medially in the thigh that extends the knee. The vastus medialis is part of the quadriceps muscle group.
The vastus medialis is a muscle present in the anterior compartment of thigh, and is one of the four muscles that make up the quadriceps muscle. The others are the vastus lateralis, vastus intermedius and rectus femoris. [1] It is the most medial of the "vastus" group of muscles. The vastus medialis arises medially along the entire length of the femur, and attaches with the other muscles of the quadriceps in the quadriceps tendon. [1]
The vastus medialis muscle originates from a continuous line of attachment on the femur, which begins on the front and middle side (anteromedially) on the intertrochanteric line of the femur. It continues down and back (posteroinferiorly) along the pectineal line and then descends along the inner (medial) lip of the linea aspera and onto the medial supracondylar line of the femur. The fibers converge onto the inner (medial) part of the quadriceps tendon and the inner (medial) border of the patella. [1]
The obliquus genus muscle is the most distal segment of the vastus medialis muscle. Its specific training plays an important role in maintaining patella position and limiting injuries to the knee. With no clear delineation, it is simply the most distal group of fibers of the vastus medialis.
The vastus medialis is one of four muscles in the anterior compartment of the thigh. [1] It is involved in knee extension, along with the other muscles which make up the quadriceps muscle. [1] The vastus medialis also contributes to correct tracking of the patella. [2]
A division of the vastus medialis muscle into two groups of fibers has been hypothesized, a long and relatively inline group of fibres with the quadriceps ligament, the vastus medialis longus; and a shorter and more obliquely oriented with group of fibres, the vastus medialis obliquus. There is as yet insufficient evidence to conclusively confirm or deny this hypothesis. [3]
Knee pain is thought to be primarily associated with specific quadriceps muscle weakness or fatigue, especially in the vastus medialis obliquus (VMO). It is known that fatigue can be caused by many different mechanisms, ranging from the accumulation of metabolites within muscle fibers to the generation of an inadequate motor command in the motor cortex. [4] Characteristics of the vastus medialis, including its angle of insertion, correlate with presence of knee joint pain (patellofemoral pain syndrome). [5] However, this syndrome is complex and definitive evidence of causality has not yet been published.
Misfiring and fatiguing of the VMO causes mal-tracking of the patella and subsequent damage to surrounding structures creating increased force on the knees, often resulting in injuries such as patellofemoral pain syndrome, anterior cruciate ligament rupture, chondromalacia, and tendinitis. [6] Through the use of electromyography, researchers can evaluate and record the electrical activity produced by the skeletal muscle of the VMO to analyze the biomechanics and detect any possible abnormalities, weakness, or fatigue. With an analysis of muscle activity of the VMO through the use of electromyography, proper rehabilitative plans and goals can be established to not only correct the already established abnormality, but even prevent such injuries if tested sooner. Preventing injuries is crucial as well as teaching proper training techniques to ensure there are no valgus collapse forces causing unplanned stress on other structures of the knee, causing asymmetry, and predisposing that individual for injury.
The leg is the entire lower limb of the human body, including the foot, thigh or sometimes even the hip or buttock region. The major bones of the leg are the femur, tibia, and adjacent fibula. The thigh is between the hip and knee, while the calf (rear) and shin (front) are between the knee and foot.
In humans and other primates, the knee joins the thigh with the leg and consists of two joints: one between the femur and tibia, and one between the femur and patella. It is the largest joint in the human body. The knee is a modified hinge joint, which permits flexion and extension as well as slight internal and external rotation. The knee is vulnerable to injury and to the development of osteoarthritis.
In anatomy, the thigh is the area between the hip (pelvis) and the knee. Anatomically, it is part of the lower limb.
The sartorius muscle is the longest muscle in the human body. It is a long, thin, superficial muscle that runs down the length of the thigh in the anterior compartment.
The patella, also known as the kneecap, is a flat, rounded triangular bone which articulates with the femur and covers and protects the anterior articular surface of the knee joint. The patella is found in many tetrapods, such as mice, cats, birds and dogs, but not in whales, or most reptiles.
The quadriceps femoris muscle is a large muscle group that includes the four prevailing muscles on the front of the thigh. It is the sole extensor muscle of the knee, forming a large fleshy mass which covers the front and sides of the femur. The name derives from Latin four-headed muscle of the femur.
The vastus intermedius (Cruraeus) arises from the front and lateral surfaces of the body of the femur in its upper two-thirds, sitting under the rectus femoris muscle and from the lower part of the lateral intermuscular septum. Its fibers end in a superficial aponeurosis, which forms the deep part of the quadriceps femoris tendon.
The vastus lateralis, also called the vastus externus, is the largest and most powerful part of the quadriceps femoris, a muscle in the thigh. Together with other muscles of the quadriceps group, it serves to extend the knee joint, moving the lower leg forward. It arises from a series of flat, broad tendons attached to the femur, and attaches to the outer border of the patella. It ultimately joins with the other muscles that make up the quadriceps in the quadriceps tendon, which travels over the knee to connect to the tibia. The vastus lateralis is the recommended site for intramuscular injection in infants less than 7 months old and those unable to walk, with loss of muscular tone.
The rectus femoris muscle is one of the four quadriceps muscles of the human body. The others are the vastus medialis, the vastus intermedius, and the vastus lateralis. All four parts of the quadriceps muscle attach to the patella by the quadriceps tendon.
The femoral nerve is a nerve in the thigh that supplies skin on the upper thigh and inner leg, and the muscles that extend the knee. It is the largest branch of the lumbar plexus.
The knee examination, in medicine and physiotherapy, is performed as part of a physical examination, or when a patient presents with knee pain or a history that suggests a pathology of the knee joint.
The adductor canal is an aponeurotic tunnel in the middle third of the thigh giving passage to parts of the femoral artery, vein, and nerve. It extends from the apex of the femoral triangle to the adductor hiatus.
The tuberosity of the tibia, tibial tuberosity or tibial tubercle is an elevation on the proximal, anterior aspect of the tibia, just below where the anterior surfaces of the lateral and medial tibial condyles end.
The anterior compartment of thigh contains muscles which extend the knee and flex the hip.
Patellofemoral pain syndrome is knee pain as a result of problems between the kneecap and the femur. The pain is generally in the front of the knee and comes on gradually. Pain may worsen with sitting down with a bent knee for long periods of time, excessive use, or climbing and descending stairs.
Patellar subluxation syndrome, is an injury that is concerned with the kneecap. Patellar subluxation is more common than patellar dislocation and is just as disabling.
A patellar dislocation is a knee injury in which the patella (kneecap) slips out of its normal position. Often the knee is partly bent, painful and swollen. The patella is also often felt and seen out of place. Complications may include a patella fracture or arthritis.
The medial patellofemoral ligament (MPFL) is one of several ligaments on the medial aspect of the knee. It originates in the superomedial aspect of the patella and inserts in the space between the adductor tubercle and the medial femoral epicondyle. The ligament itself extends from the femur to the superomedial patella, and its shape is similar to a trapezoid. It keeps the patella in place, but its main function is to prevent lateral displacement of the patella.
The vastus muscles are three of the four muscles that make up the quadriceps femoris muscle of the thigh. The three muscles are the vastus intermedius, the vastus lateralis, and the vastus medialis located in the middle, on the outside, and inside of the thigh, respectively. The fourth muscle is the rectus femoris muscle a large fleshy muscle which covers the front and sides of the femur.
Medial knee injuries are the most common type of knee injury. The medial ligament complex of the knee consists of:
This article incorporates text in the public domain from page 471 of the 20th edition of Gray's Anatomy (1918)