VMO is an abbreviation of 'vastus medialis obliquus', which is a part of the quadriceps (quads) muscle.
Page updated June 2023 by Dr Sheila Strover (Clinical Editor)
The quadriceps muscle group, showing the VMO.
Anatomy of the vastus medialis muscle
The quadriceps muscle is so-named because it has 'four heads'.
Although they come together and unite into a single quadriceps tendon at the patella, the vastus medialis seems to be more independent than the rest of the group.
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Quote from peer-reviewed paper:
"VMO is a distinct muscle within the quadriceps femoris group....sufficient to rotate the medial condyle of femur internally and the muscle could act independently."
Citation: Sawy MME, Mikkawy DMEE, El-Sayed SM, Desouky AM. Morphometric analysis of vastus medialis oblique muscle and its influence on anterior knee pain. Anat Cell Biol. 2021 Mar 31;54(1):1-9. doi: 10.5115/acb.20.258. PMID: 33262319; PMCID: PMC8017455.
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Quote from peer-reviewed paper:
"The oblique fibers of the vastus medialis (VM) are not only attached to the medial border of the patella, but they also have a small region of direct continuity with the patellar tendon."
Citation: Toumi H, Poumarat G, Benjamin M, Best TM, F'Guyer S, Fairclough J. New insights into the function of the vastus medialis with clinical implications. Med Sci Sports Exerc. 2007 Jul;39(7):1153-9. doi: 10.1249/01.mss.0b013e31804ec08d. Erratum in: Med Sci Sports Exerc. 2008 May;40(5):982. Best, Thomas [corrected to Best, Thomas M]. PMID: 17596784.
The importance of the VMO in knee rehabilitation
The VMO is the muscle that gives a lot of problem when it comes to rehabilitation of the knee after injury or surgery.
The reason for this is that the muscle fibres very readily become inhibited, and struggle to 'fire' when the patient tries to straighten the leg.
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Quote from peer-reviewed paper:
In tests of the quadriceps muscle, the authors found "[patellofemoral] effective stress was most sensitive to variations in forces in the two branches of the vastus medialis muscle, VML and VMO..."
Citation: Pal S, Besier TF, Gold GE, Fredericson M, Delp SL, Beaupre GS. Patellofemoral cartilage stresses are most sensitive to variations in vastus medialis muscle forces. Comput Methods Biomech Biomed Engin. 2019 Feb;22(2):206-216. doi: 10.1080/10255842.2018.1544629. Epub 2018 Dec 31. PMID: 30596523; PMCID: PMC6468979.
Forum discussions
- Quad exercises (mainly for the medial side)
Simple practical advice for strengthening the VMO muscle.
- Gym equipment for vmo strengthening?
Active discussion about VMO exercising.