Rectus femoris muscle | |
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Details | |
Pronunciation | /ˈrɛktəsˈfɛmərɪs/ |
Origin | Anterior inferior iliac spine and the exterior surface of the bony ridge which forms the groove on the iliac portion of the acetabulum |
Insertion | Inserts into the patellar tendon as one of the four quadriceps muscles |
Artery | Descending branch of the lateral femoral circumflex artery |
Nerve | Femoral nerve |
Actions | Knee extension; hip flexion |
Antagonist | Hamstring |
Identifiers | |
Latin | musculus rectus femoris |
TA98 | A04.7.02.018 |
TA2 | 2614 |
FMA | 22430 |
Anatomical terms of muscle |
The rectus femoris muscle is one of the four quadriceps muscles of the human body. The others are the vastus medialis, the vastus intermedius (deep to the rectus femoris), and the vastus lateralis. All four parts of the quadriceps muscle attach to the patella (knee cap) by the quadriceps tendon.
The rectus femoris is situated in the middle of the front of the thigh; it is fusiform in shape, and its superficial fibers are arranged in a bipenniform manner, the deep fibers running straight (Latin : rectus) down to the deep aponeurosis. Its functions are to flex the thigh at the hip joint and to extend the leg at the knee joint. [1]
It arises by two tendons: one, the anterior or straight, from the anterior inferior iliac spine; the other, the posterior or reflected, from a groove above the rim of the acetabulum.
The two unite at an acute angle and spread into an aponeurosis that is prolonged downward on the anterior surface of the muscle, and from this the muscular fibers arise.
The muscle ends in a broad and thick aponeurosis that occupies the lower two-thirds of its posterior surface, and, gradually becoming narrowed into a flattened tendon, is inserted into the base of the patella.
The neurons for voluntary thigh contraction originate near the summit of the medial side of the precentral gyrus (the primary motor area of the brain). These neurons send a nerve signal that is carried by the corticospinal tract down the brainstem and spinal cord. The signal starts with the upper motor neurons carrying the signal from the precentral gyrus down through the internal capsule, through the cerebral peduncle, and into the medulla. In the medullary pyramid, the corticospinal tract decussates and becomes the lateral corticospinal tract. The nerve signal will continue down the lateral corticospinal tract until it reaches spinal nerve L4. At this point, the nerve signal will synapse from the upper motor neurons to the lower motor neurons. The signal will travel through the anterior root of L4 and into the anterior rami of the L4 nerve, leaving the spinal cord through the lumbar plexus. The posterior division of the L4 root is the femoral nerve. The femoral nerve innervates the quadriceps femoris, a fourth of which is the rectus femoris. When the rectus femoris receives the signal that has traveled all the way from the medial side of the precentral gyrus, it contracts, extending the knee and flexing the thigh at the hip. [2]
The rectus femoris, sartorius, and iliopsoas are the flexors of the thigh at the hip. The rectus femoris is a weaker hip flexor when the knee is extended because it is already shortened and thus suffers from active insufficiency; the action will recruit more iliacus, psoas major, tensor fasciae latae, and the remaining hip flexors than it will the rectus femoris.
Similarly, the rectus femoris is not dominant in knee extension when the hip is flexed since it is already shortened and thus suffers from active insufficiency. In essence: the action of extending the knee from a seated position is primarily driven by the vastus lateralis, vastus medialis, and vastus intermedius, and less by the rectus femoris.
In the other extreme, the muscle's ability to flex the hip and extend the knee can be compromised in a position of full hip extension and knee flexion, due to passive insufficiency.
The rectus femoris is a direct antagonist to the hamstrings, at the hip and at the knee.
Rectus femoris strain, referred to as hip flexor strain, [3] is an injury commonly at the tendon that attaches to the patella or in the muscle itself. The injury is usually a partial tear, but could be a full tear. The injury is caused by a forceful movement related to sprinting, jumping, or kicking and is common in sports like football or soccer. The rectus femoris is prone to injury, since it crosses both the knee and the hip. Symptoms include a sudden sharp pain at the front of the hip or in the groin, swelling and bruising, and an inability to contract the rectus femoris with a full tear. [4]
The Rectus femoris tendon can cause a fragment of anterior inferior iliac spine of the hip (AIIS) to avulse in what is known as an Avulsion fracture. This is due to forceful contraction of the muscle that generates a force greater than that which holds the bone together. This is a well recognized, but unusual sports injury that can affect young athletes. [5]
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. There are 60 bones in each leg.
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In anatomy, the thigh is the area between the hip (pelvis) and the knee. Anatomically, it is part of the lower limb.
The gluteus minimus, or glutæus minimus, the smallest of the three gluteal muscles, is situated immediately beneath the gluteus medius.
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 gastrocnemius muscle is a superficial two-headed muscle that is in the back part of the lower leg of humans. It is located superficial to the soleus in the posterior (back) compartment of the leg. It runs from its two heads just above the knee to the heel, extending across a total of three joints.
The biceps femoris is a muscle of the thigh located to the posterior, or back. As its name implies, it consists of two heads; the long head is considered part of the hamstring muscle group, while the short head is sometimes excluded from this characterization, as it only causes knee flexion and is activated by a separate nerve.
The vastus medialis 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 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 semimembranosus muscle is the most medial of the three hamstring muscles in the thigh. It is so named because it has a flat tendon of origin. It lies posteromedially in the thigh, deep to the semitendinosus muscle. It extends the hip joint and flexes the knee joint.
The semitendinosus is a long superficial muscle in the back of the thigh. It is so named because it has a very long tendon of insertion. It lies posteromedially in the thigh, superficial to the semimembranosus.
The plantaris is one of the superficial muscles of the superficial posterior compartment of the leg, one of the fascial compartments of the leg.
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 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.
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 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.
The tensor vastus intermedius is a muscle in the anterior compartment of thigh. It lies between the vastus intermedius and the vastus lateralis. The term tensor vastus intermedius was given by Grob et al. in 2016, although the structure had been reported previously.
This article incorporates text in the public domain from page 470 of the 20th edition of Gray's Anatomy (1918)