Gluteus Medius

Human Movement Science & Functional Anatomy of the:

Gluteus Medius

by Brent Brookbush MS, PES, CES, CSCS, ACSM H/FS

(c) Primal Pictures

Origin: External surface of the ilium between the iliac crest and the posterior gluteal line dorsally , and the anterior gluteal line ventrally and gluteal aponeurosis just lateral to the gluteus maximus (11). Insertion: Oblique ridge on the lateral surface of the greater trochanter of the femur (11).

• The anterior and middle fibers of the gluteus medius are relatively superficial, only covered by the crural fascia. The posterior fibers slip underneath the lateral border of the gluteus maximus . Just anterior to the gluteus medius is the tensor fasciae latae . Deep to the gluteus medius is the gluteus minimus.
  • Palpation of the gluteus medius may be accomplished by exploring the lateral ilium. If you place your thumb on the PSIS (posterior Superior Iliac Spine) and your index finger just posterior to the ASIS (anterior Iliac Spine), and then with your other hand find the bony protuberance below the iliac crest that is your greater trochanter - you will create the shape of a piece of pie between your fingers. This "piece of pie" outlines the gluteus medius. Palpating the area you can feel the density of this muscle and the density of the muscle just below, the gluteus minimus . By cuing abduction, internal rotation and external rotation you can feel various fibers contract under your fingers. By doing this same exercise in prone and cuing extension, you can feel the lateral border of the gluteus maximus , and the gluteus medius fibers the disappear underneath it (12).

Nerve: Superior gluteal nerve via the sacral plexus and originating from nerve roots L4, L5, and S1 Action: Primary abductor of the Hip. (The gluteus medius makes up 60% of total abductor cross section area (3).)

• Anterior fibers internally rotate and may flex the hip
• Posterior fibers externally rotate and may extend the hip

In the illustration below, note how the superior gluteal nerve courses superior to the piriformis and is "sandwiched" between the gluteus medius and minimus. Although serious superior gluteal nerve neuropraxia is relatively rare it is worth noting the anatomy and sites for potential entrapment. Do not forget the nerve roots and the potential effect that SI Joint dysfunction may have on nerve conduction. Nerves of the posterior lower extremity – Gray’s Anatomy 20th Edition via http://en.wikipedia.org/wiki/File:Gray832.png

Integrated Function:

• Stabilization: the gluteus medius stabilizes the hip, acting as the primary frontal plane stabilization mechanism for the lumbo pelvic hip complex.
• Eccentrically Decelerates:
  • The posterior fibers eccentrically decelerate hip adduction, internal rotation, and flexion (the inability to eccentrically decelerate this movement pattern is highly correlated with knee ligementous injury, specifically the ACL and MCL).
  • The anterior fibers eccentrically decelerate hip adduction, extension and external rotation.
  • Depression of contralateral innominate (a.k.a. positive Trendelenberg Sign).
• Synergists:
  • Often the gluteus medius is paired with the abductors of the hip and is thought to work synergistically with the TFL and gluteus minimus . This assertion is not wrong; however, the function of this muscle in relation to posture , performance, and daily activity implies that the gluteus medius is more often activated in conjunction with with the gluteus maximus . You may consider the gluteus maximus and gluteus medius as your "glute complex" (see " Functional Groups "). These muscles work as your primary mechanisms of propulsion, and eccentrically decelerate adduction, flexion, internal rotation, and contralateral innominate depression. In essence, these muscle propel during acceleration, and resist collapse of the kinetic chain during deceleration. Making a mental note of this pairing will aid in the selection of corrective exercise - as the gluteus medius and gluteus maximus are often "worked" together - if one is activated, most of the time, so is the other.
• Synergistic Dominance :
  • The TFL may become synergistically dominant for an inhibited gluteus medius. A sign of this during dynamic assessment is the "knees caving-in" (functional genu valgum) during a leg press, squat, or gait. Clinical implications may include iliotibial band syndrome, hip impingement syndrome, lateral and/or anterior knee pain, and TFL trigger points .
• Primary Frontal Plane Stabilization Mechanism :
  • The most important role of the gluteus medius is to stabilize the hip, pelvis, and femur, in the frontal plane. When standing on a single leg (for example the stance phase of gait) it is the responsibility of the gluteus medius to maintain a relatively level pelvis. This function plays a significant role in maintaining optimal length/tension of the muscles of the core, and arthrokinematics of the hip, SIJ, and lumbar facets. Gluteus medius weakness and inhibition results in a drop of the opposite side of the pelvis during single leg stance, referred to as a "positive Trendelenburg sign."
  • The gluteus medius also maintains femoral alignment ensuring optimal arthrokinematic of the knee. The optimal alignment of the femur ensures better congruence between the femoral condyles and tibial plateau. This congruence is important for spreading load evenly through intra-articular tissues. The dysfunctional pattern noted in individuals with a weak or inhibited gluteus medius has high level of congruence with common wear patterns and ligament damage seen in common knee impairments.
    • An analogy to consider for exercise selection - This function is so important to optimal knee function that the traditional therapeutic method of activating the VMO for those with knee pain, is like addressing a collapsing column in a skyscraper with duck tape around the middle, as opposed to, activating the gluteus medius which is like centering and fixating that column to the I-beams in the ceiling with metal spikes.
  • By maintaining optimal alignment of the femur and pelvis (x axis = ASIS to ASIS, y-axis = ASIS to center of patella), the gluteus medius maintains optimal length/tension of hip musculature. Further, this maintains the oblique axis of the gluteus maximus muscle fibers, resulting in optimal production from force couples during hip extension. It has been my observation that optimal function of the gluteus medius is required for optimal performance of the gluteus maximus - and a more productive gluteus maximus will always lead to better performance.

Arthrokinematics:

• • • Hip: The gluteus medius plays the largest role in compression of the hip (3) and contribute to posterior rotary force.

Fascial Integration:

• • • The Gluteal Aponeurosis - is a thickening of the fascia extending from the posterior iliac crest to the gluteus maximus and part of the gluteus medius. This may reinforce the assertion made above that the gluteus maximus and medius are recruited synergistically, perhaps in relation to tension created in this fascial tissue and sensory input to the CNS from mechanoreceptors in this fascial sheath. Further, this fascia runs continuous with superficial fibers of the thoracolumbar fascia that invest in the latissimus dorsi. Could it be that the gluteus medius should be included in the muscle synergy of the posterior oblique subsystem (POS) ?
    • Origin on the Greater Trochanter - The gluteus medius has it's own tendon, but invests in the periosteum of the greater trochanter adjacent to the gluteus minimus , piriformis , and vastus lateralis . Although there are distinct borders on the greater trochanter I will be giving this relationship more thought in the future. To view this relationship yourself check out this link to a wonderfully written study - Greater Trochanter

[caption id="attachment_78483" align="alignnone" width="640"] http://aclandanatomy.com/multimediaplayer.aspx?multimediaid=10528141[/caption]

Note: The above photograph appears to be a cadaver dissection that was performed on an individual who had assumed an anterior pelvic tilt. This gives the illusion that the majority of gluteus medius fibers are anterior to the greater trochanter; however, the proportion of gluteus medius fibers anterior to posterior is generally split 50/50 or more slightly more posterior than anterior.

Behavior in Postural Dysfunction:

This muscle has a tendency toward adaptive lengthening and under-activity. Due to the propensity towards an increase in length and a decrease in activity, the gluteus medius is generally activated and strengthened (exercises below).

• In Upper Body Dysfunction (UBD) this muscle does not play a significant role. Occasionally, a loss of shoulder range is related to over-activity and adaptive shortening of the latissimus dorsi related to Sacroiliac Joint Dysfunction (SIJD ) or Lumbo Pelvic Hip Complex Dysfunction and should be treated accordingly. In essence, the "upper body dysfunction" in these individuals is disguising the root issue.
• In Lower Leg Dysfunction (LLD) this muscles play its most significant role. The inability of the gluteus medius to eccentrically decelerate femoral internal rotation and adduction results in dyskinesis of the hip and knee ("knees bow in" during the Overhead Squat Assessment ) , and is often paired with over-activity of the tibial external rotators and/or the Deep Longitudinal Subsystem (DLS) . In a variation of the commonly seen "knees bow in" dysfunction, the "knees bow out" masking the gluteus medius weakness. Don't be fooled - the knees bowing out is the result of synergistic dominance by the piriformis , adductor magnus, and biceps femoris , and post release and lengthening techniques for these over-active structures the gluteus medius will still require attention.
• In Lumbo Pelvic Hip Complex Dysfunction (LPHCD) this muscle plays a significant, although less obvious, role. The gluteus medius seems to play a crucial role in the optimal function of the gluteus maximus , and their length and activity are often paired in movement dysfunction .
• In Sacroiliac Joint Dysfunction (SIJD) both gluteus medius often become inhibited. However, as SIJD often results in an asymmetrical weight shift best results may be seen by initially activating the gluteus medius only on the side of the shift.

In short, these muscles should be the focus of activation exercise when postural dysfunction is noted (signs of length change listed below), and as these muscles are so commonly under-active it may be "good practice" to include gluteus medius exercise in all warm-up, core, and lower body conditioning programs.

Signs of Altered Length/Tension and Tone:

• • • Overhead Squat:
      • Asymmetrical Weight Shift - Long/Under-active on side of dysfunction
      • Knees Bow In - Long/Under-active on both sides
      • Anterior Pelvic Tilt - Long/Under-active on both sides
    • Single Leg Squat:
      • Knees Bow In - Long/Under-active
      • Turn In - Long/Under-active
    • Goniometry (Indication of restriction and over-activity):
      • Hip Rotation (internal or external) > 45° with soft end feel
    • Special Tests for Gluteus Medius Weakness:
      • Single Leg Stance (Hip Drop indicates weak Gluteus Medius and is referred to as a Positive Trendelenburg Sign)
      • Manual Muscle Testing (MMT) of Gluteus Medius
    • Palpation of Gluteus Medius
      • Soft during active hip abduction

Gluteus Medius dysfunction may contribute to the following:

• Knee Pain
  • Patellar tendonitis (Jumper's Knee)
  • Lateral knee pain (Runner's Knee)
  • Iliotibial band syndrome
  • Hamstring tendonitis
  • Generalized knee pain
• Sacroiliac Joint Pain and Dysfunction
• Hip Pain
  • Impingement Syndrome
  • Ischial tuberosity bursitis
  • Generalized hip pain
• Lumbar spine pain
  • Excessive lordosis
  • Functional scoliosis
• Lateral shift of lumbar spine
• Ankle/Foot Pain
  • Ankle sprain
  • Ankle impingement
  • Achilles tendonitis
  • Plantar fasciitis

Posterior View of the Human Body – Gray’s Anatomy 20th Edition via Bartleby.com

Trigger Points in Gluteus Medius... or are they?

• Occasionally, reference is made to gluteus medius trigger points; however, long under-active structures are not as prone to trigger point development as short/over-active structures. At the very least, the presence of trigger points in the gluteus medius is uncommon, resulting in very few techniques focused on release and lengthening of this muscle . It is more likely that trigger points assessed in proximity to the gluteus medius are actually trigger points in the gluteus minimus which lies deep to the gluteus medius, and/or the TFL and piriformis ; all of which have a propensity toward over-activity.

Specific Techniques for the Gluteus Medius:

Gluteus Medius Isolated Activation Side Stepping for Reactive Integration: Side Stepping Progressions Side Hop for Reactive Integration: Gluteus Medius Activation Circuit: Subsystem Integration:

Bibliography:

1. Phillip Page, Clare Frank , Robert Lardner , Assessment and Treatment of Muscle Imbalance: The Janda Approach © 2010 Benchmark Physical Therapy, Inc., Clare C. Frank, and Robert Lardner
2. Dr. Mike Clark & Scott Lucette, “ NASM Essentials of Corrective Exercise Training ” © 2011 Lippincott Williams & Wilkins
3. Donald A. Neumann, “Kinesiology of the Musculoskeletal System: Foundations of Rehabilitation – 2nd Edition” © 2012 Mosby, Inc.
4. Michael A. Clark, Scott C. Lucett, NASM Essentials of Personal Training: 4th Edition , © 2011 Lippincott Williams and Wilkins
5. Leon Chaitow, Muscle Energy Techniques: Third Edition , © Elsevier 2007
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7. Shirley A Sahrmann, Diagnoses and Treatment of Movement Impairment Syndromes, © 2002 Mosby Inc.
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11. Florence Peterson Kendall, Elizabeth Kendall McCreary, Patricia Geise Provance, Mary McIntyre Rodgers, William Anthony Romani , Muscles: Testing and Function with Posture and Pain: Fifth Edition © 2005 Lippincott Williams & Wilkins
12. Andrew Biel, Trail Guide to the Human Body: 4th Edition, © 2010
13. Carolyn Richardson, Paul Hodges, Julie Hides. Therapeutic Exercise for Lumbo Pelvic Stabilization – A Motor Control Approach for the Treatment and Prevention of Low Back Pain: 2nd Edition (c) Elsevier Limited, 2004
14. Craig Liebenson, Rehabilitation of the Spine: A Practitioner’s Manual, (c) 2007 Lippincott Williams & Wilkins
15. Stuart McGill, Low Back Disorders: Second Ediction © 2007 Stuart M. McGill
16. Robert Schleip, Thomas W. Findley, Leon Chaitow and Peter A. Huijing. Fascia: The Tensional Network of the Human Body. (c) 2012 Elsevier Ltd.

[caption id="" align="alignnone" width="368"] Posterior Hip Image – Gray’s Anatomy 20th Edition via http://commons.wikimedia.org/wiki/File:Gray434.png[/caption] © 2013 Brent Brookbush Questions, comments, and criticisms are welcome and encouraged.