Muscle Of The Week: What Is The VMO?

Vastus Medialis Oblique The Most Famous Quadriceps Muscle

Vastus Medialis Oblique or the VMO for short makes up part of the quadriceps muscles, a group of muscles that are positioned in the front of your thigh. Specifically the vastus medialis sits medially on the inside of your thigh where along with the three other quadriceps muscles its primary function is to extend the knee. The VMO is considered by many as an important muscle in knee function and rehabilitation, this is mainly through its roll in helping control the position (tracking) of the kneecap (patella).

VMO Anatomy

The VMO makes up a part of the quadriceps of which there are four muscles (hence “quad” = four and “ceps” = head, four parts to the muscle group). The other muscles that make up the quadriceps are the vastus lateralis, vastus intermedius and rectus femoris. The part of the quadriceps which is known as the VMO is positioned just above the medial aspect of the kneecap and the muscle fibres travel towards their insertion point at a somewhat oblique angle. The origin of vastus medialis oblique is from the medial side of the thigh bone (feumr) and inserts into the quadriceps tendon (as can be seen above) on the inside border of the knee cap.

The Function Of Vastus Medialis Oblique

Vastus medialis oblique works with the other quadriceps muscles in extending the knee and is considered to have an important role in maintaining kneecap positioning. An ideal quadriceps contraction should keep the kneecap tracking smoothly and upwardly through the femoral groove as they work to straighten the knee. The VMO is often given extra significance here and is considered important in keeping the kneecap “tracking” correctly in this femoral groove. It is suggested that poor contraction timing, or weakness of the VMO may play a roll in “mal-tracking” of the kneecap and subsequently contribute to patellofemoral pain.
The kneecap’s position is partially influenced by the pull between the quadriceps muscles. Commonly diagnosed tracking issues with the kneecap are considered to occur in theory partly due to either the vastus lateralis or ITB pulling too strongly, or the VMO pulling too weakly (or a bit of column A and a bit of column B). Hence the VMO is frequently targeted for specific strengthening exercises in knee rehabilitation programs.

Disclaimer: Sydney Physio Clinic does not endorse any treatments, procedures, products mentioned. This information is provided as an educational service and is not intended to serve as medical advice. Anyone seeking specific advice or assistance regarding Muscle Of The Week: What Is The VMO? should consult his or her general practitioner, sports medicine specialist, personal trainer or physiotherapist.