The Six Hip Muscles Nobody Talks About
And Why They Matter More Than Your Glute Medius
By Emilie Perz | Sequential Body
Every yoga class names the glute medius. External rotation cues, hip stability cues, lateral hip strength cues — the glute medius is the answer to almost every question about the hip in modern movement education. It is not, however, the most important hip stabilizer. It is the most superficial one.
Underneath it, a group of six small, deep muscles is doing the more consequential work. They are almost never named. Most practitioners have never heard of them. And yet they are the reason your hip joint stays organized under load in every standing pose you have ever practiced.
Meet the Deep Six
The six deep external rotators of the hip, or as I learned, collectively known as the “deep six” - are the piriformis, the obturator internus, the obturator externus, the gemellus superior, the gemellus inferior, and the quadratus femoris. They sit deep to the glute medius, wrapping around the posterior hip and attaching along the femur. The anatomical analogy is exact: they are the rotator cuff of the hip, in the same way that the four rotator cuff muscles of the shoulder hold the humeral head in the glenoid while the larger muscles move the arm.
Each muscle has a specific role. The piriformis externally rotates the hip when extended and shifts to an abductor when the hip flexes past roughly 60 degrees. The obturator internus externally rotates when the hip is extended and abducts when flexed past 90 degrees. It works so closely with the two gemelli muscles that the three are often treated as a single functional unit. The obturator externus is the deepest of the six, sitting closest to the joint, where its primary contribution is femoral head stabilization rather than rotation. The quadratus femoris is the most inferior and arguably the most powerful compressor of the femoral head into the acetabulum — the muscle most directly responsible for what anatomists call centration.
Their Job Is Not Rotation — It’s Centration
The word centration describes something specific: keeping the head of the femur organized inside the acetabulum as the hip moves through range. Not rotating it. Not producing motion. Holding it.
This is the distinction that gets lost in almost every conversation about hip anatomy in yoga. The deep six are classified as external rotators because that is a motion they can produce. But their primary functional role, particularly under load in standing poses, or in any situation where weight is passing through the hip, is to compress the femoral head into the socket and prevent it from translating. That is joint-level stabilization. It has nothing to do with how far into external rotation your hip can go.
Compare this to what the glute medius actually does. The glute medius is primarily a hip abductor, and secondarily a pelvic stabilizer. In fact, its most important job is keeping the pelvis from dropping on the opposite side during single-leg loading, which is why a weak glute medius produces a Trendelenburg gait. It works at the pelvis level. The deep six work at the joint level. These are different hierarchies of stabilization, and conflating them is the source of most of the confusion in yoga hip cueing.
Why the Cue “Firm the Outer Hip In” Works
One of the most common cues in yoga standing poses is “firm the outer hip in,” “draw the outer hip toward the midline,” “hug the hip into the socket” and it is a direct access point to the deep six, even when neither the teacher nor the student knows that.
When these muscles engage, they literally compress the femoral head into the acetabulum. The sensation people feel when a good teacher gives this cue. It’s a sense of the hip organizing, becoming more stable, finding the weight more clearly and it truly is the deep six doing their job. The joint is being centrated. The femoral head is being held.
This matters in Warrior II because the front hip is externally rotated and loaded simultaneously which are the conditions under which the deep six need to be active. It matters in tree pose because the hip is in a held external rotation while balance is being maintained on a single leg. It matters in half moon because the standing hip is under the full load of the body with minimal base of support. In all of these poses, the deep six are the mechanism that keeps the joint intelligent under load. The glute medius keeps the pelvis level. The deep six keep the femur in the socket.
Why They Are Never Named
There are two reasons the deep six remain invisible in most yoga education. The first is anatomical: these muscles sit deep to the glute max and glute medius, with no surface representation. You cannot see them contract. You cannot palpate them easily. There is no visible shape change that signals their engagement. In a culture where movement education has been influenced by visible muscle development and aesthetic feedback, muscles that don’t show up on the surface of the body tend not to show up in the vocabulary either.
The second reason is practical: you cannot cue the deep six by name and get a reliable response. A student told to “activate your quadratus femoris” will look confused and do nothing. But a student told to “firm the outer hip in” will feel the engagement immediately. The muscles respond to proprioceptive and mechanical cues, not anatomical naming. This is why understanding the mechanism matters more than transmitting the terminology.
Different Depths, Different Jobs
The practical takeaway is straightforward: the glute medius and the deep six are not interchangeable, and they are not competing for the same job. The glute medius stabilizes the pelvis in the frontal plane. The deep six stabilize the femoral head in the acetabulum. One works from the outside in. The other works at the source.
The reason this distinction matters in practice: a practitioner who has strong, well-recruited glute medius function but poorly recruited deep six will experience hip instability, anterior femoral glide, and over time, the kind of chronic hip joint irritation that passes for “tightness” in most yoga conversations. The sensation of the hip not quite working is often a centration problem, not a flexibility problem. And centration is the deep six’s entire job.
Building This Understanding into Your Practice
The Sequential Body approach builds this understanding directly into how classes are sequenced and cued. Every loaded hip position — every standing pose that asks the hip to carry weight through range — is prepared with attention to joint organization before demand is added. The cues access the deep six without naming them, because what practitioners need is not a vocabulary lesson. It is the experience of their hip working correctly.
That experience is available in every practice. Most people have just never been given the instruction that produces it.
If you want to build a practice with this understanding built in — the Sequential Body app is where that lives.