Rectus femoris muscle
Musculus rectus femoris
Rectus femoris is the straight, central part of the quadriceps group in the anterior thigh, crossing both the hip and the knee.
At a glance
- English
- Rectus femoris muscle
- Latin (TA2)
- Musculus rectus femoris
- System
- Muscle
- Region
- Lower limb
- Side
- Paired, left and right
About the rectus femoris muscle
The rectus femoris is the most superficial part of the quadriceps femoris, the large extensor group of the anterior thigh. It runs straight down the middle of the thigh, which gives it its name, and covers much of the vastus intermedius beneath it, with the lateral and medial vasti on either side.
Unlike the vasti, which arise from the shaft of the femur, the rectus femoris starts on the pelvis. A straight head leaves the anterior inferior iliac spine, while a reflected head springs from a groove on the ilium just above the rim of the acetabulum. The two join into a spindle-shaped belly with a bipennate fibre pattern. Low in the thigh it becomes the central part of the quadriceps tendon, which wraps the patella and continues as the patellar ligament to the tibial tuberosity.
Because it crosses both the hip and the knee, it has two roles. It extends the knee together with the rest of the quadriceps, and it flexes the hip, swinging the thigh forward during walking, running and kicking. It works best as a hip flexor when the knee is bent and as a knee extender when the hip is straight, so it is particularly active in kicking a ball.
That two-joint course makes it the quadriceps muscle most often strained, usually at sprint starts or in kicking sports, and in adolescents the straight head can pull a fragment of bone off the anterior inferior iliac spine. The thigh is also the commonest site of myositis ossificans after a heavy blow, and the femoral nerve supplies the whole muscle group.
Attachments, action and supply
- Origin
- Straight head: anterior inferior iliac spine; reflected head from the ilium just above the acetabulum.
- Insertion
- Base of the patella through the quadriceps tendon, and on to the tibial tuberosity through the patellar ligament.
- Action
- Extends the knee and flexes the hip.
- Nerve supply
- Femoral nerve (L2, L3, L4).
- Blood supply
- Mainly the descending branch of the lateral circumflex femoral artery.
Anthromica
See the rectus femoris muscle where it really sits, with every layer of the body around it.
- Every layer, one body. Peel from muscle to bone, nerve, vessel and organ, and turn it any way.
- English and Latin. Every structure named the way your exam names it.
- Quiz until it sticks. Short drills on the structures you keep missing.
Free to start. No card.
