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Quadriceps Femoris Muscle

Quadriceps femoris is a group of muscles located in the anterior compartment of the thigh (also known as the extensor compartment of the thigh). The muscles are the great extensors of the knee joint, and form the bulk of the anterior thigh, covering almost all of the anterior and both lateral and medial sides of the femur. The quadriceps femoris is an extremely powerful muscle group, essential for motions such as walking, running, jumping, and climbing. They also assist in flexion of the thigh at the knee joint and stabilising the patella during movement. 

The name ‘quadriceps femoris’ means ‘four headed femoral muscle’, thus the group consists of four individual muscles, the rectus femoris, the vastus lateralis, the vastus medialis, and the vastus intermedius. The muscle group is more commonly referred to as the ‘quads’. Rectus femoris is located in the midline, while vastus lateralis forms the bulk of the lateral thigh, vastus medialis is in the medial thigh, and vastus intermedius lies deep to the rectus femoris between vastus lateralis and medialis. All of the muscles of the quadriceps muscle group converge to form a common tendon, the quadriceps tendon, which becomes continuous with the patellar ligament. This article will outline the detail of these muscles, including origin, insertion, action, innervation, and blood supply.

Key facts about the quadriceps femoris muscle
Origins Rectus femoris: anterior inferior iliac spine, superior margin of the acetabulum of hip bone
Vastus medialis: intertrochanteric line of femur
Vastus lateralis: linea aspera, greater trochanter of femur
Vastus intermedius: anterior surface of shaft of femur
Insertions Tuberosity of the tibia (via the patellar ligament)
Innervation Femoral nerve (L2-L4)
Actions

Hip joint: Thigh flexion (rectus femoris only) 

Knee joint: Leg extension

Action

The quadriceps tendon inserts onto the base of the patella. Distal to the patella, it continues as the patellar ligament. The patellar tendon and patellar ligament are essentially the same thing. Because tendons attach muscle to bone, patellar tendon is used to describe the insertion of the quadriceps femoris muscle as it crosses the knee joint to attach to the tibial tuberosity. However as this structure crosses the knee joint, it incorporates the patella, thus the term patellar ligament is used to describe how the fibres attach the apex of the patella to the tibial tuberosity since ligaments connect bone to bone. All the muscles contributing to the quadriceps femoris muscle insert onto the tibial tuberosity via this tendon. 

The quadriceps femoris muscles are a big topic to learn! Feeling a bit overwhelmed? Learn the attachments, innervations and functions of these muscles faster and easier with our lower extremity muscle chart.

Collectively, the quadriceps femoris muscle group act as the main extensors of the leg at the knee joint. The rectus femoris muscle also flexes the thigh at the hip joint, and can simultaneously extend the knee whilst also flexing the hip. The vastus medialis is important in counteracting lateral movement of the patella during movements of the knee. Insufficiency of this muscle is a common cause of patellar pain and instability. The quadriceps femoris muscle group are the antagonist to the hamstring group in the posterior thigh.

Rectus Femoris

Key facts about the rectus femoris muscle
Origins Anterior inferior iliac spine, superior margin of acetabulum
Insertions Tibial tuberosity (via patellar ligament) 
Innervation Femoral nerve (L2-L4)
Action Hip joint: Thigh flexion;
Knee joint: Leg extension

The rectus femoris is the only muscle in the quadriceps femoris group that crosses both the hip and knee joints. It is a fusiform muscle, meaning the belly of the muscle tapers into a narrower tendon on both ends. It has two points of origin and two heads, from the anterior inferior iliac spine (the straight head), and from a groove on the ilium above the acetabulum (the reflected head). Proximally, the fibers of the rectus femoris muscle are superficial to the capsule of the hip joint, vastus intermedius, the anterior borders of the vastus lateralis and medialis muscles, the lateral circumflex humeral artery, and branches of the femoral nerve. The distal fibers of the muscle end as a flat aponeurosis that narrows into a thick flat tendon that inserts onto the base of the patella. This forms the superficial central part of the quadriceps tendon. 

As the rectus femoris crosses both the hip and knee joint, it acts at both of these joints. It produces flexion of the thigh at the hip joint and extension of the leg at the knee joint, thus it is sometimes referred to as the ‘kicking muscle’. 

The proximal part of the muscle is covered by the tensor fasciae latae, the iliacus, and the sartorius muscles. The vasti muscles, the capsule of the hip joint, the lateral circumflex femoral artery and branches of the femoral nerve are located deep to the rectus femoris muscle. It is innervated by the femoral nerve (L2-L4).The blood supply to the rectus femoris muscle is derived from the artery of the quadriceps, which is a branch of the profunda femoris artery, as well as contributions from the lateral circumflex humeral artery. Venous drainage of rectus femoris is by the venae comitantes, or accompanying veins to the arteries. These form part of the deep venous drainage of the lower limb. Venous return from the rectus femoris muscle is to the profunda femoris vein, which in turn drains to the femoral vein.

Vastus Medialis

Key facts about the vastus medialis muscle
Origins Intertrochanteric line of femur
Insertions Tibial tuberosity (via patellar ligament)
Innervation Femoral nerve (L2-L4)
Action Knee joint: Leg extension 

Vastus medialis covers most of the medial aspect of the femur. It originates from the lower part of the intertrochanteric line, the spiral line, the medial lip of the linea aspera, the proximal part of the medial supracondylar line, and the medial intermuscular septum. Its fibers pass inferiorly and anteriorly, becoming an aponeurosis and inserting onto the medial aspect of the patella and the quadriceps tendon.

The lower fibers are almost horizontally oriented, and leave a clearly distinguishable surface feature medial to the superior half of the patella. This is sometimes individually referred to as vastus medialis obliquus. The vastus medialis is partially deep to the rectus femoris and sartorius muscles, and forms the medial wall of the adductor canal in the middle part of the thigh. 

It is innervated by the femoral nerve (L2-L4), and produces extension of the leg at the knee joint. The blood supply to the muscle is by the superior, middle and inferior branches of the superficial branch of the femoral artery, as well as minor branches from the profunda femoris and genicular arteries. Venous drainage of the muscle is by the venae comitantes to the profunda femoris vein and popliteal vein via the genicular veins. 

Vastus Lateralis

Key facts about the vastus lateralis muscle
Origins Linea aspera of femur, greater trochanter of femur
Insertions Tibial tuberosity (via patellar ligament) 
Innervation Femoral nerve (L2-L4)
Action Knee joint: Leg extension

The vastus lateralis is the largest component of the quadriceps femoris group, forming the bulk of the lateral thigh. It originates from the upper part of the intertrochanteric line, the anterior and inferior borders of the greater trochanter, the lateral lip of the gluteal tuberosity, and the proximal half of the lateral lip of the linea aspera. Its fibers converge on a flat tendon that inserts onto the base and lateral aspect of the patella and blend with the fibers of the quadriceps tendon. It then goes on to insert onto the tibial tuberosity via the patellar ligament.

The vastus lateralis is covered proximally by the fascia lata (the deep fascia of the thigh) and the aponeurotic attachments of the tensor fasciae latae and gluteus maximus muscles. The vastus intermedius muscle lies medial to it, and branches of the femoral nerve and the lateral circumflex femoral artery are located between the two muscles. Posteriorly, the lateral intermuscular septum separates it from the biceps femoris in the posterior compartment of the thigh. 

The vastus lateralis muscle is innervated by branches of the femoral nerve (L2-L4). Arterial blood supply to the muscle is by branches of the lateral circumflex femoral artery and the first perforating branch of the profunda femoris artery. Venous drainage is to the profunda femoris vein.

Vastus Intermedius

Key facts about the vastus intermedius muscle
Origins Anterior surface of femoral shaft
Insertions Tibial tuberosity (via patellar ligament)
Innervation Femoral nerve (L2-L4)
Action Knee joint: Leg extension 

The vastus intermedius muscle arises from the anterior and lateral surfaces of the proximal two-thirds of the femoral shaft, and from the distal part of the lateral intermuscular septum. Its fibers form an aponeurosis that forms the deep part of the quadriceps tendon. It is also attached to the lateral aspect of the patella and the lateral condyle of the tibia.

The vastus intermedius and vastus medialis muscles often appear fused together, but are separated from each other by a narrow cleft that extends superiorly from the medial border of the patella, sometimes as far up as the intertrochanteric crest. The vastus intermedius muscle is almost entirely covered by the remainder of the quadriceps femoris muscles. It is only laterally that part of the vastus intermedius is superficial to the vastus lateralis muscle. 

The muscle is innervated by branches of the femoral nerve (L2-L4), and receives blood supply from branches of the profunda femoris artery. Venous drainage is by the venae comitantes to the profunda femoris vein.

Articularis Genus

Key facts about the articularis genus muscle
Origins Distal part of the anterior femur
Insertions Superior reflection of synovial membrane
Innervation Femoral nerve
Action Retraction of the suprapatellar burse during leg extension

Articularis genus (also known as the articular muscle of the knee) is a small muscle that is fully distinct from the vastus intermedius muscle. Though distinct from the vastus lateralis, medialis, intermedius, and rectus femoris muscles, the articularis genus muscle contributes to the overall action of the quadriceps femoris muscle group by acting on the soft tissue surrounding the knee joint to produce fluid extension of the leg at the knee. It arises from the distal part of the anterior femur and inserts onto a superior reflection of synovial membrane. The muscle retracts the suprapatellar bursa superiorly during extension of the leg at the knee joint. In doing so, it pulls the synovial membrane superiorly, preventing it from being compressed between the patella and the femur during knee extension.

Articularis genus is innervated by branches of the femoral nerve. Its blood supply is from the femoral artery and its venous drainage is the femoral vein.

Clinical Notes

Clinical analysis of the quadriceps group involves extending the knee against resistance, in the supine position with the hip flexed.

The knee jerk or patellar reflex is a clinical test involving the patellar ligament. It tests spinal cord segments L2, L3, and L4. Striking the patellar ligament causes it to stretch, activating the muscle spindle stretch receptor in the quadriceps femoris muscle. The stretch causes activation of a reflex arc, which cause the quadriceps femoris muscles to contract and oppose the stretch of the tendon. The sensory input from the force applied to the patellar ligament is relayed back to the spinal cord through the L2, L3 and L4 spinal nerves. The sensory stimulus is processed at this level of the spinal cord, and as these roots are the same as the motor roots for the quadriceps femoris muscle (i.e. the femoral nerve), a motor stimulus is relayed through the same spinal nerve roots to the muscle causing it to contract. This is an important mechanism in maintaining balance. If there is an overstretch in the patellar ligament in real life situations, for example, when overbalancing backwards, the reflex arc is activated, and causes a contraction of the quadriceps muscle to extend the knee and correct the overbalancing. This prevents the person from falling backwards. Absence of the patellar reflex could indicate could indicate a lesion to the spinal cord at the level of the nerves that innervate the quadriceps femoris muscle (L2, L3, and L4). Such injuries are usually caused by physical trauma, one of the leading causes being road traffic collisions. These injuries are considered irreversible, so treatment entails mainly physical therapy techniques in order to maintain and strengthen existing function of the muscles.

As it is an extremely large muscle mass, the muscles of the anterior thigh are also susceptible to contusions, specifically in individuals that participate in high impact sports. A contusion causes bleeding from capillaries and blood infiltration into the muscle and surrounding soft tissues. They are commonly referred to as a bruise. These usually do not require medical attention, and heal on their own over time.

Quadriceps Femoris Muscle - want to learn more about it?

Our engaging videos, interactive quizzes, in-depth articles and HD atlas are here to get you top results faster.

Sign up for your free Kenhub account today and join over 1,134,051 successful anatomy students.

“I would honestly say that Kenhub cut my study time in half.” – Read more. Kim Bengochea Kim Bengochea, Regis University, Denver

Show references

References:

  • F. Netter: Atlas of Human Anatomy, 6th Edition, Elsevier Saunders (2014)
  • J. A. Gosling, P. F. Harris, J. R. Humpherson, I. Whitmore, P. L. T. Willan: Human Anatomy, Colour Atlas and Textbook, 5th Edition, Mosby Elsevier (2008), p. 260

  • K. L. Moore, A. M. R. Agur, A. F. Dalley: Essential Clinical Anatomy, 5th Edition, Wolters Kluwer (2015), p. 329-337

  • R. Drake, A. W. Vogl, A. W. M. Mitchell: Gray’s Anatomy for Students, 3rd Edition, Churchill Livingston Elsevier (2015), p. 589-603

    S. Standring: Gray’s Anatomy: The Anatomical Basis of Clinical Practice, 14th Edition, Churchill Livingston Elsevier (2008), p. 1372-1374

Author:

  • Niamh Gorman
  • Alexandra Osika
  • Adrian Rad
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