Quadriceps Muscle

Author: Scott A. Sheffield MS

Last update: Nov 2nd, 2022

Introduction

The quadriceps muscle, which derives its name from the Latin word for four-headed, is in practice a group of four muscles;  rectus femoris, vastus lateralis, vastus intermedius, and vastus medialis. It is the largest muscle in the human body, and the sole extensor of the knee joint.

In this tutorial, we will learn about the insertion, origin, innervation and action of these four muscles.

Rectus femoris muscle

Attachments

Origin (proximal attachment):

Anterior inferior iliac spine and supracetabular groove of the ilium

Insertion (distal attachment):

Tibial tuberosity (via patellar ligament)

Vastus lateralis muscle

Attachments

 Origin (proximal) attachments:

Greater trochanter of femur, intertrochanteric line, gluteal tuberosity and lateral aspect of linea aspera.

Insertion (distal) attachments:

Just like all the other three muscles, vastus lateralis inserts into the tibial tuberosity via the patellar ligament and also into the patella itself.

Vastus medialis muscle

Attachments

 Origin (proximal) attachments:

Intertrochanteric line, spiral line and linea aspera, and the medial lip of linea aspera of femur

Insertion (distal) attachments:

Tibial tuberosity (via patellar ligament) and the patella itself

Vastus intermedius muscle

Attachments

 Origin (proximal) attachments:

Anterior and lateral surface of the femoral shaft.

Insertion (distal) attachments:

Tibial tuberosity (via patellar ligament) and the patella itself

Innervation of quadriceps femoris

Femoral nerve (L2-L4).

Action of quadriceps femoris

As mentioned in the introduction of this tutorial, quadriceps femoris extends the leg at the knee joint. It’s also worth noting that the rectus femoris also helps flexing the thigh at the hip joint.

Test yourself