Vastus Medialis Muscle

Overview

Muscle Group: Vastus Medialis is part of the Quadriceps

Action: Extends (straightens) the knee

Origin: Large portion of the anteromedial aspect of the femur

Insertion: Medial border of the patella (joins with the other quads tendons), medial condyle of the tibia and the tibial tuberosity via the patella tendon

Nerve Supply: Femoral nerve (L2, L3, L4)

Special Function: Knee and kneecap stability especially in the final stage of knee extension

AKA: Vastus Internus or teardrop muscle

Vastus Medialis In-Depth

Vastus Medialis is the most medial of the quadriceps muscles, found on the medial (inner) side of the front of the thigh. It works with the other quadriceps to straighten the knee.

It has an extensive origin on the anteromedial surface of the femur (thigh bone) which begins at lower medial end of the intertrochanteric line, runs down around the medial aspect of the spiral line, the medial lip of the linea aspera, continues on to the upper two thirds of the medial supracondylar line, medial intermuscular septum and the adductor magnus tendon.

The upper fibres (often referred to as Vastus Medialis longus) mainly pass straight downwards whereas the lower fibres (often referred to as Vastus Medialis Oblique) pass forwards, almost horizontally. The muscle fibres join with one of the other quadriceps muscles, rectus femoris, the medial border or the kneecap and the medial condyle of the tibia, fusing with the deep fascia and replacing the lateral joint capsule. The fibres that join with the other quadriceps muscles surround the patella and attach to the tibial tuberosity on the front of the tibia (shin bone) just below the kneecap via the patella tendon.

This muscle helps the joint to lock in the final stages of knee extension as the femur rotates medially. The portion just above the kneecap, often referred to as Vastus Medialis Oblique (VMO), is often thought of as being anatomically and functionally distinct from the rest of the muscle, though this is subject to debate. The VMO plays an important role in stability particularly of the kneecap by resisting the tendency for the patella to move laterally (outwards) due to the femoral angulation and reducing the risk of kneecap dislocation. In some cases, usually following an injury or due to biomechanics, the VMO part of the muscle can become weak, fatigued, mis-fire or switch off altogether. This can lead to problems with patella tracking (how the kneecap moves) and anterior knee pain such as patellofemoral pain syndrome (aka runner’s knee), chondromalacia and tendonitis. 

Vastus Medialis as a whole works with the other quadriceps muscles to straighten the knee, all working strongly through their entire range. They work in activities such as standing up from a seated or kneeling position, going up and down stairs, cycling and squatting.

What Next?

Here are some related topics you may be interested in:

1) Quadricep Stretches: How to tell if you would benefit from stretches and easy to follow video guides

2) Quadricep Strengthening: How to strengthen the quads and other knee muscles

3) Knee Muscles: Learn about the different muscles that control the knee and how they work together

4) Common Knee Injuries: Find out everything you need to know about the most common knee injuries and how to treat them

Go to Anatomy Guide or Homepage

Muscles of the Lower Limb

Rectus Femoris
Vastus Lateralis
Vastus Medialis
Vastus Intermedius

Biceps Femoris
Semimembranosus
Semitendinosus
Popliteus

Gluteus Maximus
Gluteus Medius
Gastrocnemius
Soleus

Check out our book - Knee Arthritis: Take Back Control. Available in paperback or on Kindle

All the info you need, in our new book
Find out more

Read Reviews/ Buy Now

$3.99/£2.99




See Also

Knee Strengthening Exercises

Knee Stretches

Diagnose Your Pain

Knee Anatomy


Search This Site


Visitor Comments

“This is one of the best self-help & info sites of any medical condition I've ever seen. Excellent work.” Amy, UK

"Your site and exercises have been a lifesaver! The explanations are so clear.  Thanks for your help and excellent work."  Claire, US

"I'm an RN. This is really useful, easy to understand info."
Jan, US

“Thanks to KPE.com. Lots of improvement after just two days.” Suresh, India

"This is the best self-help site I have ever seen for knee pain. It is very difficult to find such a comprehensive volume of information on one site without being advised to "Just purchase this product!" Many, many thanks" Jennifer, US

"Superb site, many thanks, so much helpful content especially the targeted strengthening exercises for me.” Gerri, UK

“Thank you so much, your response makes so much sense. Thank you again for your time in answering my questions.” Cynthia, US

"Your website is a gold mine, thank you very much."
Gavril, Denmark

"Thank you for this website and all the information, especially the videos. I suffer from knee stiffness and pain when standing and now I have some exercises I can do - thanks to you." Claire, US

"I LOVE your website. Out of all the others, yours is so informational and easy to read." Michelle, US

"This is the best site dealing with knee problems that I have come across. I will be putting the stretches and exercises into practise. Thank you!"
Margaret, S. Africa

"The information given by you is fabulous. Thank you." Nihal, India

"Your site is excellent! It covers everything you need to know about knee pain and it's treatment in an easy to understand format. Thanks!" Linda, US

"Brilliant website - highly recommended! And as nurse (25yrs exp) its written expertly and is very explanatory and easy to understand. Thank you!" Jo, UK