The Quads? Maybe. But Also Maybe Not...
Here’s a fun fact. There’s a fifth quad muscle. Who knew? Well, maybe some of you. But I am only just now learning about this. Which makes me think two things: 1 - what we know about our own anatomy is, truly, constantly being updated and evolving. And 2 - What do we do with this information? I mean, not just that there is a fifth muscle in a group of muscles that were named for the fact that there are four of them. But also, how does this change our approach? My first thought is more of an ongoing reflection about what we think we know. And this is a great topic of conversation but not the one I am focusing on for this article. My second thought is more of a question… And I have answers.
Ultimately these 2 points are related. If what we know is always changing, then what we do with that knowledge has to be part of the conversation. In this instance, we have always known the Quadricep muscles to be the Vastus Lateralis, the Vastus Intermedius, the Vastus Medialis and the Rectus Femoris. The Quads. Four of them. But now there is a fifth. Where it is and what it does must influence how we work.
Technically, there has been knowledge of a fifth quadricep since 2016 (or even before then but this was when it was officially named). In a study of 26 cadavers, a fifth quadricep muscle, the Tensor Vastus Intermedius (TVI), was found in 22 of those.* And also technically, it follows, that not everyone has a TVI. But 22 out of 26 is not a small percentage. Similar to the Psoas Minor or the Palmaris Longus, though, anomaly muscles get us thinking. What does it do? What does that mean for soft tissue manipulation or dysfunction? And, perhaps most importantly, does its existence change the name of the quads?
And so, I give you the Tensor Vastus Intermedius. You will find this muscle, on those who have it, close to the hip and near it’s similarly named relative, the Tensor Fascia Latae. Its proximal attachment lies on the proximal and lateral surfaces of the shaft of the femur and/or the Greater Trochanter - depending on your source.* And its distal attachment veers medially and merges with the rest of the quad muscles just above the patella. It is not a vast muscle, though. It looks like the anterior upper leg version of the Plantaris muscle - a burst of muscle fibers at the top with a long, tail-like tendon that reaches down to make contact.*
The actions of this little guy are 2 fold, but not what you might expect. Instead of lending a hand in extending the knee along side its siblings, it actually stands in the middle and sort of pulls them back into line if they get too cocky. Specifically, it may play a role in controlling the movement of the patella by counteracting the force of the Vastus Medialis. In other words, if the Vastus Lateralis gets too big for its britches, the TVI acts to reel it in and keep the patella in place. Also, it may act to exert tension on the aponeurosis of the Vastus Intermedius. Or, similar to how the TFL operates, it creates a tension in connective tissue structures to maintain a sense of stability - which we all need.
What exactly does this mean for massage therapy? Our approach to the quadricep muscles does not have to change except for this: learning about anatomy and their respective physiologies always guides how we work. But because what we know is always shifting and moving, our ability to be fluid with the translation of what is in our brains to what our hands do will always be essential. The knowledge that a fifth quad muscle exists gives us a greater ability to be even more nuanced and detailed with our techniques. Simultaneously, though, the whole person that is on your table is still your best guide.
Try this: With your client supine, have them situate the leg you are focused on so that their knee is bent and that foot is on the table. Sit on their foot to help stabilize their leg. With both hands on either side of the knee, curl your fingers so that your finger pads sink down into the aponeurotic tissue just superior to the patella. Then start sliding from knee to hip methodically, working from medial to lateral or vice versa or both. Notice the density or pliability of their tissues. And check in with your client about what they feel. With this extra wisdom about the quads in your pocket, spend a little extra time rapidly drawing short lines from the top of the patella to about mid thigh with a decent amount of pressure. Then clasp your hands at the top of the leg near the hip, lean back and give the TVI a little extra love.
Remember, too, that educating your client is one of your most powerful techniques. Tell them about this new element that might be influencing their knee pain or muscle tension. Remind them that you are always reading up on research and theories. And boost their confidence in who you are as a bodyworker. Your passion for this craft will be infectious. As for what we should call the quads now that we know more about them? Pentriceps? Quads 2.0? Vuads? What do you think?