Rectus Femoris Muscle: Anatomy, Location, and Functions Performed by It

As a member of the quadriceps, the rectus femoris is an important muscle. The quadriceps family is the only member to travel posterior to the iliac crest and anterior to the iliac tuberosity, making it a large, thick mass of muscle in the upper anterior middle compartment of the thigh.

It lies above the vastus medialis and lateralis and the superior medial portion of the vastus intermedius. A straight line is described by the Latin word rectus. The rectus femoris got its moniker, as it's a straight muscle that travels down the inner aspect of the thigh. It acts to extend the knee and aid the iliopsoas in flexing the hip, as it crosses both joints, so it also flexes the hips.

The patella may be positioned higher than it would be on the opposite leg if the rectus femoris were longer. When the knee bends less than 80 degrees, or when the superior patellar groove is very visible, it may indicate that the rectus femoris is abnormally short.

Rectus Femoris Muscle: Anatomy and Location

The R. femoris muscle plays a role in bending the knee. (Image via Pexels/Maksim Goncharenok)

To help extend the knee or flex the thigh, there's a muscle called the rectus femoris that runs from the pelvis to below the knee (the patellar tendon). This muscle is one of the quadriceps muscles present at the front of the thigh. It rests right in the middle of the upper thigh. The vastus medialis, vastus intermedius, and the vastus lateralis are the other muscles that make up the quadriceps.

The quadriceps are a group of muscles in the upper thighs. It's on the front of the thigh muscle, to be exact (in the very front). From the hips to the knees, it's the most superficial muscle in the body that runs very close to the skin.

There are two connection points where the R. femoris muscle attaches to the femur bone (this connection is called a head). The outer hip is home to the first head, also known as the straight or direct head. The reflected head is the opposite and begins above the hip joint.

In the knee, it attaches to the patellar tendon (patella). The artery providing the blood supply is the lateral femoral circumflex artery located in the upper thigh. A signal is sent to it from the brain via the femoral nerve.

Rectus Femoris Action and Functions

This muscle extends from the hips to the knees. (Image via Flickr)

When kicking a football or soccer ball, the rectus femoris is put to good use. It's a common tool for cyclists.

It's a component of the hip flexors, a group of muscles responsible for bringing the thighs and trunk closer together during a flexion movement. The hip flexors are comprised of the following muscles:

• Psoas major
• Illiacus
• Rectus femoris
• Pectineus
• Sartorius

The knee is also lengthened as a result. When the hip is extended, it can extend the knee with great force. However, the R. femoris becomes less effective in extending the knee when the hip is flexed, as when sitting, and the other quads must take over.

Again, if the knee is bent, the R. femoris is unable to flex the hip very far, so the other hip flexors must assist. The gluteus maximus, piriformis, obturator externus, obturator internus, and the superior and inferior gemelli are all synergist muscles for the R. femoris, as they perform similar actions, such as flexing the hip.

The hamstrings oppose the R. femoris by acting as antagonistic muscles. It follows that they have the opposite effect. Learning more about the anatomy of leg muscles can help you understand your body better and work out the muscles that are important.

Rectus Femoris Origin and Insertion

Squats work out the R. femoris muscle (Image via Pexels/Andrea Piacquadio)

The rectus femoris begins at the superior alar aspect of the ilium and the anterior inferior iliac spine (AIIS).

A direct tendon (DT), an indirect tendon (IT), and a variable third head make up its proximal tendinous complex (PTC). When the direct tendon and the indirect tendon join, it becomes one common tendon (CT). The anterior superior iliac spine and CT are joined by a membrane.

Jointly originating from the quadriceps, the rectus femoris, vastus medialis, vastus lateralis, and vastus intermediu are all inserted into the patella and tibial tuberosity (via patellar ligament).

Exercises that Work Out the Rectus Femoris

Lunges are also good at working out the muscle. (Image via Pexels/Mikhail Nilov)

The rectus femoris can be strengthened through squatting exercises or lunges, whether using only your own bodyweight or additional weight in the form of a barbell or dumbbells.

Leg press and leg extension machines are two of the most popular leg machines in your gym used to work out this muscle. If walking and running make up the bulk of your cardio routine, working the quads should be a part of your fitness routine.

Protecting your health and mobility by keeping your rectus femoris muscles strong is essential. Talk to a doctor if you have issues with this muscle's function or if you have severe pain in the front of your thigh. The optimal function of this crucial muscle can be maintained through targeted exercises for legs and doing quad stretches.