Deep Rotators of the Hip

Human Movement Science & Functional Anatomy of the:

Deep Rotators of the Hip:

• Gemelli
• Obturators
• Quadratus Femoris
• > Note: Piriformis discussed separately

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

Deep Rotators of the Hip via Visiblebody.com - http://info.visiblebody.com/Portals/189659/images/Lateral-rotator-muscles-hip-gluteal.png

Anatomy (in order from superior to inferior):

Whats in a name:

• Obturator - from the latin root obturare, meaning to "block an opening." The obturators "block" the obturator foramen of the ischium.
• Gemellus - is a diminutive of the Latin word geminus (think of the zodiac sign "Gemini") meaning a twin. There are two gemelli muscles similar in size shape and function.
• Quadratus Femoris - Latin root quadratus means square shaped and femoris is obviosely in reference to the femur. "A square shaped muscle on the femur"

Gemellus Superior

• Origin: External surface of the spine of the ischium (11).
• Insertion: With a common tendon shared by the obturator internus and gemellus ingerior into the medial surface of the greater trochanter of the femur.
• Nerve: Nerve to the gemellus superior via the sacral plexus originating from nerve roots S1, S2 and sometimes L5
• Action: External rotation and horizontal abduction of the hip

Obturator Internus

• Origin: Internal or pelvic surface of the obturator membrane and margin of the obturator foramen, pelvic surface of the ischium posterior and proximal to the obturator foramen, and to a slight extent the obturator fascia (11).
• Insertion: With a common tendon shared by the gemelli into the medial surface of the greater trochanter of the femur, proximal to the trochanteric fossa.
  • The obturator internus makes a nearly 90º as it passes through the lesser sciatic notch which is covered by hyaline cartiliage (3).
• Nerve: Nerve to the obturator internus via the sacral plexus originating from nerve roots L5, S1 and S2
• Action: External rotation and horizontal abduction of the hip

Gemellus Inferior

• Origin: Proximal part of the tuberosity of the ischium (11).
• Insertion: With the tendon of the obturator internus into the medial surface of the greater trochanter.
• Nerve: Never to the gemellus inferior (also innervating the quadratus femoris) via the sacral plexus originating from nerve roots S1, S2 and sometimes L5
• Action: External rotation and horizontal abduction of the hip

Insertions on the posterior aspect of the Greater Trochanter - Gray's Anatomy: 20th Edition - http://upload.wikimedia.org

Obturator Externus

• Origin: Rami of the pubis and ischium, and the external surface of the obturator membrane (11).
• Insertion: Trochateric fossa of the femur.
• Nerve: Obturator nerve via the sacral plexus originating from nerve roots L3 and L4
• Action: External rotation and may assist in adduction

Quadratus Femoris

• Origin: Proximal part of the lateral border of the tuberosity of the ischium (11).
• Insertion: Proximal part of the quadrate line, extending distally from the intertrochanteric crest.
• Nerve: The nerve to the quadratus femoris (shared nerve with gemellus inferior) via the sacral plexus originating from nerve roots L4, L5, S1 and sometimes S2
• Action: External rotation and may assist in adduction.

Insertions on the Ischium - Grays Anatomy: 20th Edition - http://upload.wikimedia.org

Location and Palpation:

• The muscles above are listed in order from superior to inferior, and are the deepest of the posterior hip muscles. The gemellus superior lies just inferior to the strongest of the deep rotators, the piriformis . The deep rotators, save the piriformis lie deep to the sciatic nerve which passes between the piriformis and gemellus superior. The gemellus superior, obturator internus and gemellus inferior are bordered anteriorly by the posterior hip capsule, while the quadratus femoris abuts the obturatur externus which lies just posterior to the adductor musculature. The insertion of the piriformis lies on the superior aspect of the greater trochanter between the insertions of the gluteus minimus  and gluteus medius , and the tendons of the gemellus superior, obturator internus and gemellus inferior lie just medial to the insertion of the piriformis. The obtrator externus inserts just inferior to the gemellus inferior in the trochanteric fossa and the quadratus femoris more inferior still, inserting on the intertrochanteric crest.
  • The piriformis muscle may be palpated by finding the spinous process of S2 with your thumb (the first prominent spinous process on the sacrum), and finding the greater trochanter with your index finger. The nearly horizontal line between these two points should outline the piriformis. Sinking your fingers deep to the gluteus maximus and running your fingers gently up and down should result in the relatively thin band like muscle being “strummed” underneath your fingers. Be careful not to compress the sensitive sciatic nerve (12).
  • The quadratus femoris may be palpated by finding the nearly horizontal muscle lying between the ischial tuberosity and the inferior aspect of the greater trochanter. Placing your fingers between these bony landmarks, sinking deep beyond the fibers of the gluteus maximus , and asking the individual to externally rotate will "pop" this muscle into your fingers (12).
  • Although they are tough to differentiate, the gemellus superior, obturator internus and gemellus inferior may be felt as horizontal bands, deep to the more vertically arranged gluteus maximus, between the piriformis and quadratus femoris.

Netter's Anatomy Atlas - Nerves of the Buttock

Integrated Function:

• Stabilization: These muscles stabilize the hip joint
• Eccentrically Decelerates:
  • All of these muscle decelerate hip internal rotation
  • The gemellus superior, obturator internus, and gemellus inferior may eccentrically decelerate horizontal adduction
  • The obturator externus and quadratus femoris may assist in eccentric deceleration of abduction and horizontal abduction.
• Synergists:
  • Along with the piriformis,  the deep rotators externally rotate, horizontally abduct and stabilize the posterior hip.
  • The deep rotators may play a role in a synergy that results in their over-activity due to dysfunction and inhibition of the gluteus maximus and the gluteus medius  - most apparent in dysfunction resulting in "Knees Bow Out" during an "Overhead Squat Assessment ." These muscles becomes synergistically dominant along with the biceps femoris and the posterior head of the adductor magnus  during hip extension (eccentric flexion). For more on this relationship and specific techniques for addressing this issue click on the article “Posterior Hip and Thigh Flexibility ."

Posterior Hip - Have to be honest… not even really sure what specifics to get from this illustration, I just thought it was a really cool image of the posterior hip. There is something to be gained from the layering and depth of various muscles… http://www.sarkomzentrum.ch

Arthrokinematics:

• Hip: These muscles may contribute to a posterior rotatory force and anterior glide of the femoral head along with an adaptively shortened posterior capsule. Although I could not find a specific reference, it would be interesting to determine if these muscles are among the few that impart an inferior force on the femur, and help to balance the immense forces contributing to superior glide.

Obturator Fascia – http://healingartsce.com/online-courses/online-courses/images/mm_deep-front-line-Pelvic-floor.jpg

Fascial Integration:

• Two possibilities, however, I could not find any further evidence than the mere insinuation that a relationship exists.
  • The deep rotators may reinforce and invest in the posterior capsule of the hip joint. This finding may implicate these muscles in hip pain originating from arthrokinematic dysfunction along with the gluteus minimus and rectus femoris .
  • The obturator internus is invested and enveloped by the obturator fascia, which may implicate this muscle in synergy with pelvic floor musculature.

Fascia covering the obturator internus and the pelvic floor - http://spirittrail.files.wordpress.com/2013/01/pelvic-diaphragm-female.jpg

Obturatur Externus abutting Adductor Brevis: Anterior View - RVU Anatomy - www.rvuanatomy.com

Subsystems:

• The deep rotators of the hip do not play a role in the Core Subsystem  synergies, but may follow the lead of the piriformis, which may be implicated as having a role in the Deep Longitudinal Subsystem (DLS) via the sacrotuberous ligament. These muscles often become over-active as a group in various movement compensations.

Behavior in Postural Dysfunction:

These muscles adopt the same behavior as the piriformis (with the exception of sacroiliac joint dysfunction), and have a tendency toward over-activity, but may be short or long depending on the compensation pattern (posture) adopted. We find altered activity and length in lower leg dysfunction, lumbo pelvic hip complex dysfunction and sacroiliac joint dysfunction. For more information on these predictive models of dysfunction click on the links below:

• Lower Leg Dysfunction (LLD)
• Lumbo Pelvic Hip Complex Dysfunction (LPHCD)
• Sacroiliac Joint Dysfunction  (SIJD)

If Lower Leg Dysfunction (LLD) presents with "Knees Bow In" during an Overhead Squat Assessment , than the deep rotators are implicated as long and over-active. However, if LLD presents with "Knees Bow Out" the muscles of the posterior hip and thigh (click on the hyperlink for flexibility techniques) including the deep rotators, pirifomis , biceps femoris , and posterior head of the adductor magnus are short and overactive.

As above, if Lumbo Pelvic Hip Complex Dysfunction (LPHCD) presents with "Knees Bow In" than the the deep rotators may be long and over-active, but generally it is not a priority in treatment. If LPHCD presents with "Knees Bow Out" than the deep rotators are implicated as short and overactive and may be release and stretched.

In Sacroiliac Joint Dysfunction (SIJD) the compensation pattern adopted and side of dysfunction must be carefully assessed. As a counternutator of the sacrum the piriformis is often short and overactive on the side of SIJD, but the piriformis may also become short and overactive on the side opposite the shift. Commonly, the side of dysfunction is opposite the side of the shift implicating only unilateral piriformis shortening, but careful assessment of the SIJ should be used to confirm findings.

Although, the deep rotators generally follow the behavior of the piriformis they do not directly affect sacral motion and their length will be determined by concurrent dysfunction at the hip arising from SIJD. It is important to note which side presents with "Knees Bow In" and which presents with "Knees Bow Out". An example of the deep rotators adopting different behavior than the piriformis can be seen when the "Knee Bows In" on the side of a counternutated sacrum (the dysfunctional side). In this case the piriformis is short and overactive while the deep rotators are long. Treatment would include release techniques may to all, but it would be more appropriate to stretch the piriformis via external rotation above 90º of hip flexion.

**The Deep Rotators may Contribute to the Following Pathologies:

**

• Knee Pain
  • Patellar tendonitis (Jumper's Knee)
  • Lateral knee pain (Runner's Knee)
  • Generalized knee pain
• Hip Pain
  • Impingement Syndrome
  • Greater Trochanteric bursitis
  • Generalized hip pain
• Lumbar spine pain
  • Excessive lordosis
  • Inadequate lordosis
  • Functional scoliosis
• Piriformis Syndrome
  • Generally presents as sciatica, but is thought to be caused by the sciatic nerve bisecting or piercing the piriformis rather than coursing underneath it.
• Sciatica
  • A long or short and overactive piriformis, along with an overactive gemellus superior may mechanically compress the sciatic nerve leading to irritation.
• Pelvic Floor Dysfunction via the obturator fascia

Sagittal Cross Section of the Hip - http://upload.wikimedia

Signs of Altered Length/Tension and Tone:

• Overhead Squat:
  • Assymetrical Weight Shift - Short/Overactive side Opposite Shift
  • Knees Bow Out - Short/Overactive
  • Posterior Pelvic Tilt - Short/Overactive
  • Anterior Pelvic Tilt - Long/Overactive
  • Knees Bow In - Long/Overactive
• Single Leg Squat:
  • Hip Hike - Short/Overactive
  • Hip Drop (Positive Trendelenburg) - Long/Overactive
• Goniometry (Indication of restriction and over-activity):
  • Hip Internal Rotation < 45° w/ muscular end feel (at 90º of hip flexion)
    • Note: A hard or capsular end feel may be partially caused by deep rotator tightness, but is often confounded by tightness and over-activity in other structures resulting in anterior glide syndrome or anterior capsule impingement (example: TFL, Psoas, Adductors, Posterior Capsule)
  • Hip External Rotation < 45° (at 90º of hip flexion) w/ muscular end feel (confirmed with similar findings in prone)
• Palpation of Deep Rotators
  • Tenderness (indication of over-activity)
  • Trigger points (indication of over-activity and chronic postural dysfunction)

Not a great image, but very few available

The "Long and Overactive" Conundrum:

Very few muscles behave in a way that leads to an increase in length and an increase in activity. Generally, an increase in length leads to under-activity, latent activation and weakness. Although muscles that are long are often activated/strengthened, muscles that are over-active often become synergistically dominant for prime movers and using activation techniques may reinforce this relationship. In the case of the deep rotators - it often become synergistically dominant for weak/inhibited gluteus maximus  and gluteus medius , but due to the variation in compensation patterns between individuals it may also become short or long. When the deep rotators are long and overactive they are generally released, but NOT stretched. If the deep rotators are short and overactive than you may release and stretch. Any strengthening that may be necessary will be accomplished by reducing over-activity (release techniques) and using gluteus medius activation exercises, in which they play a small but meaningful role.

It is the author's view that muscles that are long/overactive should be released only - stretching and activation techniques should be avoided.

Specific Techniques for the Piriformis:

Piriformis Self-administered Static Release (Note, review the "Location and Palpation" section above; these muscles may be released using the same techniques used for the piriformis, but moving the role closer to the ischial tuberosity)

Piriformis Self-Administered Active Release (Note, review the "Location and Palpation" section above; these muscles may be released using the same techniques used for the piriformis, but moving the role closer to the ischial tuberosity):

Piriformis Static Stretch and Modifications (Note, review the "Anatomy" section above; these muscles will be affected using the piriformis stretching techniques, specifically those that emphasize horizontal adduction):

Gluteus Medius Activation (May be effective for integrating "long" deep rotators of the hip):

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Bibliography:

© 2014 Brent Brookbush

Questions, comments, and criticisms are welcome and encouraged.