Gluteus Medius - The Muscle that Keeps You from Toppling Over Sideways
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Updated May 01, 2015.
The gluteus medius muscle is a fan shaped muscle located on the side of your hip. This location positions the gluteus medius as a key posture muscle, and one that plays an important role in back health. As you'll see, the gluteus medius is a hip abductor muscle, and an antagonist muscle to (antagonist means to oppose) the inner thigh muscles (called adductors.)
Gluteus Medius - What's So Special About It?
The hallmark contribution of the gluteus medius muscle is the fact that it keeps you from toppling over sideways when you walk and stand.
It helps keeps the pelvis aligned, stabilized and balanced, through movement, which is necessary for exercising therapeutically as well as preventing injury and managing pain.
A critical but often overlooked function of the gluteus medius to maintain hip alignment when you stand on one leg. This means it plays a role in walking, running and some standing balance exercises. In this capacity, the gluteus medius contracts isometrically - in other words, no movement at the joint occurs even though the muscle is working.
Related: Exercise Your Posture Muscles
Gluteus Medius - The Anatomy and Movement
The gluteus medius originates on the external surface of the outside of the ilium. (The ilium is is your hip bone.) It traverses downward - narrowing as it goes - to insert on a rather large knob of bone located on the outside of the upper thigh bone. This knob of bone is called the greater trochanter. If you could visualize the muscle from the side, you'd see it as a fan shape that starts at the greater trochanter (where it looks a bit like a stem) and fans up and out to cover the side of the hip bone as mentioned above.
The gluteus medius is one of several muscles - each in their own location and with their own specialized action around the hip joint - that connects the thigh bone and the pelvis.
The job of the gluteus medius is to abduct the thigh, relative to the pelvis.
But abduction can happen another way, too. When you stand with your feet planted and stationary, you likely can tilt your trunk to one side. While side tilting does involve some spinal movement, it also involves pelvic tilting. Pelvic tilting during standing abduction is accomplished by a 2 things: A contraction of the gluteus medius on the same side, and sideways sliding of the pelvis toward the opposite direction in an effort to maintain balance (this is technically a hip joint movement.) As you can see, this type of hip abduction is much more complex than simply moving the lower extremity out to the side, as it involves spine, pelvis, and hip action.
Joint Movement and Planning Your Therapeutic Exercise Program
Why does this matter? Well, many people have a limited understanding of joint movement. They think, for example, that the sole job of a hip muscle like the gluteus medius is to take the leg away from the center line of the body. But each joint in the body has two or more bones. Movement can occur in either one - with the other bone remaining stationary. Knowing this may help you tailor your selection of therapeutic exercises to your goal, condition and/or preferred level of challenge.
By the way, most therapeutic or corrective exercise programs aimed at relieving low back pain include strengthening and stretching exercises for all the muscles that surround the hip joint. This is because the hip joint is key for body stability and locomotion. In fact, people often believe - whether consciously or not - that support for their lumbar spine is supposed to come from back and core muscles. While it certainly doesn't hurt to have these muscles in good condition, many times an opportunity to support the body weight and posture from lower down - where leverage is better - is missed. This area includes, of course, the hip joint and greater trochanter, as discussed above. Without hip muscle strength and flexibility, your body posture may be at least partially in a state of collapse, which may lead to unnecessary compression or loading on the joints of your spine.
Related: Try a Basic Back Exercise Program
Sources:
Moore, Keith, L. and Dalley, Arthur, F. Clinically Oriented Anatomy. 5th Edition. Lippincott, Williams and Wilkins, A Wolters Klower Company.
Tortera, Gerard J. Principles of Human Anatomy. 6th Edition. Biological Sciences Textbooks, Inc. New York. 1996. Baltimore. 2006.
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