Quadriceps femoris

What Is Quadriceps Femoris?

The quadriceps femoris muscle group is located at the front of your thigh bone (femur) and runs from the bottom of your shin bone to the top of your calf bones. It attaches to several other muscles including those in your hip region. The quadriceps femoris plays a role in stabilizing and extending certain leg segments such as the knee, ankle, foot, and toes.

When you walk or run, the quadriceps femoris works together with the hamstrings to stabilize your legs. When these two muscles contract, they pull on ligaments and tendons that hold your joints in place.

If these tissues are not properly supported, then there is potential for injury. For example if one of these structures were to tear, it could cause pain and possibly even require surgery.

How Does Quadriceps Femoris Work?

Quadriceps femoris consists of three main groups: Type I, Type IIA, and Type IIB. Each type has its own specific functions. These include increasing range of motion (ROM), preventing excessive forward lean during movement, and improving speed and power production.

The rectus femoris initiates knee extension, which occurs when the foot is pointed forward. The vastus medialis also enables knee extension when the foot is pointed forward.

It also helps to prevent the thigh from swinging medially (closer to centerline of body) during walking and running. The vastus intermedius works to prevent excessive leaning, increase speed of movement, and allow foot to turn outward during walking and running. The vastus lateralis initiates knee extension when the foot is pointed outward. The final muscle is the

vastus intermedialis, and it works with the rectus femoris to extend the knee. This occurs when the foot is pointed forward.

Quadriceps Muscles and Knee Injuries

These muscles are very important for protecting your knee from injuries such as tears or damages to the ligaments and tendons. The rectus femoris also prevents the knee from giving way and supports your body weight when you walk or run up and down stairs.

Muscle weakness in this area can lead to patellar or quadriceps tendonitis. If left untreated, it can eventually lead to a ruptured quadriceps tendon. The hip abductors are also vital for preventing excessive leaning. In combination with the iliopsoas muscle, they prevent sideways movement of the upper leg bones. Weakness can lead to a Trendelenburg gait, where the body leans to one side.

Quadriceps Muscle Facts

These large muscles make up about 1/3 of your thigh and are responsible for several important functions in your body. They are divided into four subgroups based on location and function: rectus femoris, vastus medialis, vastus intermedius, and the vastus lateralis.

They are responsible for extending the knee as well as other key functions in your body.


Each muscle in the quadriceps group attaches to the femur bone at roughly the same place, just below and inside the hip joint. The rectus femoris attaches slightly lower than the rest of the group, right around the hip joint itself.


The quadriceps femoris all insert, or end, at the patella (knee cap) as well as around the tendon that attaches the patella to the tibia (shin bone).

Nerve Supply

All of the quadriceps muscles are supplied by the femur nerve which is a branch of the posterior division of the sciatic nerve (L4-S2).


All of the muscles in the quadriceps group, with the exception of the rectus femoris, take part in knee extension which is moving the lower leg away from the body. The rectus femoris only takes part in hip extension (moving the hip backwards).

Major Arteries

All of the muscles in this group are supplied by the profunda femoris artery which is a branch of the femor Artery.

Major Veins

The venae comitantes (companion veins) drain the blood from the muscles.

Quadriceps Contraction

Knee extension is when the quadriceps muscle contracts and the lower leg moves away from the body. This movement is a result of hip extension which causes the knee to straighten out.

Sciatic Nerve Pain

Pain in the butt and lower back could be caused by tightness or inflammation in one or more of the muscles in this group. It may also be due to a herniated intervertebral disk (slipped disk).

Sports that Benefit from the Quadriceps Muscles

All sports that involve sprinting, jumping, running, or kicking benefit from strong quadriceps muscles. Common sports that benefit from these muscles include: basketball, football, hockey, and soccer.

Sources & references used in this article:

Capillary supply of the quadriceps femoris muscle of man: adaptive response to exercise by P Andersen, J Henriksson – The Journal of physiology, 1977 – Wiley Online Library

Does neuromuscular electrical stimulation strengthen the quadriceps femoris? by L Bax, F Staes, A Verhagen – Sports medicine, 2005 – Springer

Quadriceps femoris muscle angle: normal values and relationships with gender and selected skeletal measures by MG Horton, TL Hall – Physical therapy, 1989 – academic.oup.com

Functionally relevant thresholds of quadriceps femoris strength by LL Ploutz-Snyder, T Manini… – The Journals of …, 2002 – academic.oup.com