Pelvic, Hip and Core Stability From Grégoire Lason and Luc Peeters, The International Academy of Osteopathy, www.osteopathy.eu Also visit: http://www.osteoapps.eu - A must have for every osteopath and health care provider. Simple to use and no unnecessary information. It keeps your knowledge sharp for daily patient care! Also look for iBooks in the iBook store from Luc Peeters and Grégoire Lason.

1. Pelvic, Hip and Core Stability
Luc Peeters, MSc.Ost. – Grégoire Lason, MSc.Ost.
Principals of The International Academy of Osteopathy
www.osteopathy.eu
Osteopaths often talk about mechanical cause-consequence chains in the lower
extremities. For example: a mechanical lesion (loss of mobility) in the iliosacral joint
can influence the mobility and stability of the foot.
If we look at these mechanical connections, we must be aware that a more important
issue here is that the pelvic girdle needs to be stabile and that there must be a
correct core stability.
With a stabile pelvis and good core stability, lots of strains and injuries in the lower
extremities can be treated and even avoided. This is important not only for daily
patients but even more for athletes and the follow up of these athletes towards
prevention of injuries.
1. Pelvic and Hip Stability
1.1. Body Load
In a standing position, the body load comes on the promontorium of the sacrum.
From there the load is transmitted through the sacroiliac joints that form an arch.
Weight is then taken to the hip joints.
The ilia form pubic struts, which neutralize the forces on the femur.
Sitting causes compression forces at the ischial tuberosities.
Body
SI joint weight
Arch
Acetabula
Compression
Femur
Sitting
Weight bearing of pelvis
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2. Pelvic ring
In a standing position, the sacrum is loaded with the superincumbent weight. Primary
vertebral load on the sacral promontorium causes the sacrum to rotate anterior. This
is called primary load on S1.
The posterior sacroiliac capsule takes the tensile stress. This causes the caudal part
of the sacrum to move posteriorly causing a counter-balancing tensile stress on the
sacrospinous and sacrotuberous ligaments. Relatively, the iliac bones rotate
posteriorly.
The weight bearing forces join at the inferior transverse axis. Under load, the sacrum
tilts anterior. The more load, the more anterior tilt of the sacrum. This induces the
lumbar spine in more lordosis.
This caudal gravity load on the sacrum with tensile stretch on the posterior capsule
and the sacrospinous- and sacrotuberous ligaments happens around the ITA, thus
compressing the inferior part of the SI joints lateromedially on this S3 level.
Primary load force at S1
40°
ITA (L3 level)
Compression at S3 level
= self-bracing
10°
Sacrum in weight bearing (redrawn from Vleeming)
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3. On the cephalic side of S3 (on the iliac bone) there is an ilial ridge. This prevents S3
to move cranially.
Ilial ridge
ITA (L3 level)
Ilial ridge postero-superior from the ITA
After load bearing, the gravity line is anterior to the sacral axis. The gravity line stays
posterior to the acetabula causing a general posterior pelvic tilt and creating a
dynamic, balanced tension on the pelvic ligaments. The posterior pelvic tilt decreases
the lumbar lordosis.
The ligamentary stability of the pelvis in the sagittal plane is maintained by a good
condition of the posterior sacroiliac capsule and the sacrospinous- and
sacrotuberous ligaments.
The basic muscular balance is done by the lower paravertebral muscles and the
coccygeal muscles. Secondary the piriformis m. and the sacral part of the gluteus
maximus m. provide a counter force for the anterior sacral rotation.
Posterior
sacroiliac
capsule and
lower
paravertebral
muscles
Sacrospinous,
sacrotuberous
ligaments and
coccygeal
muscles
Ligamentary stability and muscular balance in the sagittal plane
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4. To have an optimal functioning pelvic girdle that spreads tension equally over the
joints and capsuloligamentary structures, the correct locking mechanism (self-
bracing) must be in place. Therefore the condition of the posterior SI capsule and
sacrospinous- and tuberous ligaments must be optimal.
Despite good condition of these ligamentary structures, they are not sufficient to
maintain a good self-bracing, thus keeping the appearance of lesions to a minimum.
There is also a need for a good functioning muscular system that maintains the self-
bracing mechanism intact.
Three muscle slings (chains) are supposed to contribute to force closure of the
SI joints:
• A longitudinal muscle sling.
• A posterior oblique muscle sling.
• An anterior oblique muscle sling.
The longitudinal muscle sling consists of the combination of the low paravertebral
muscles attaching to the sacrum, the deep layer of the thoracolumbar fascia and the
sacrotuberous ligament, which is connected to the long head of the biceps femoris
muscle.
Tension in this muscle sling will stabilize the SI joint in 3 ways:
• Contraction of the low paravertebral muscles will anteriorize the sacrum. This
increased the tension on the posterior SI capsule thus leading to more force
closure of the SI joints.
• Contraction of these muscles will also inflate the thoracolumbar fascia leading
to more force closure.
• Due to the anatomical relation with the sacrotuberous ligament, the
contraction of these muscles will increase tension on the ligament thus
increasing the closure of the SI joint.
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5. Paravertebral
muscles +
thoracolumbar
fascia
Sacrospinous-
and
sacrotuberal
ligs.
Biceps femoris m.
Longitudinal muscle sling
The posterior oblique sling is the coupled function of the latissimus dorsi muscle and
the gluteus maximus muscle. Both muscles function as synergists. Contraction will
directly optimize stabilization of the SI joints.
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6. Latissimus dorsi m.
Gluteus maximus m.
Left Right
Posterior oblique sling
The anterior oblique sling consists of the external and internal oblique muscles as
well as of the transverse abdominis muscle (connection via rectus sheet).
Muscle contraction of this sling also increases the SI stabilization (self-bracing
mechanism).
External and internal
oblique m.,
transverse abdominis
m.
Right Left
Anterior oblique sling
For example sitting with the legs crossed reduces strongly the tone of the anterior
oblique sling. This is because sitting with crossed legs increases mechanically the SI
compression and friction. Reducing this muscle tone diminishes this compression
and friction.
A good stability of pelvis and hips means:
• Line of gravity between the inferior transverse axis of the SI joint and the
acetabula.
• Good, harmonious ligamentary tension.
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7. • Good harmonious muscular balance.
• Correct anatomical angulation of the hip.
Secondary load force at S3
Posterior
pelvic (ilial)
tilt around
the hip Anterior
sacrum tilt
around the
ITA
Gravity line and weight balance
1.2. The Hip
The capsular thickenings form a spiral around the hip. In extension these fibres
become taut with the result that the head of the femur is held securely in the
acetabulum and the joint becomes "locked" or "close-packed" - the position of
maximum stability and firmness for the hip.
All the major joints (hip, knee, ankle) become close-packed at full extension and this
coincides with the limb becoming a rigid, vertical, weight-bearing pillar. This is clearly
the essential prerequisite for standing upright on two legs i.e. the adoption of bipedal
stance.
When standing erect the centre of gravity passes behind the hip joint. This should
result in hyperextension at the hip. It is especially the iliofemoral lig. that withstands
this extension.
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8. Iliofemoral lig. withstanding extension in standing position
1.3. Leg Length Difference
If there is an anatomical leg length difference, the left and right ligamentary tension is
different. Although the body can compensate, this anatomical leg length difference
will reduce the stability and mechanical resistance to avoid lesions.
Not every leg length difference however is anatomical. A pelvic torsion can cause an
apparent leg length difference.
Importance of hip- and pelvic stability: they are the basis for the core stability.
2. Core Stability
Core stability means the ability of the lumbo-pelvic-hip complex to prevent buckling of
the vertebral column and to return it to equilibrium following perturbation.
Coordination and co-contraction of muscles provide spine stiffness. In other words “it
is the ability to control the position and motion of the trunk over the pelvis to allow
optimum production, transfer and control of force and motion to the terminal segment
in integrated kinetic chain activities”. (Kibler et al 2006)
Core stability can also be described as the possibility to continually and
instantaneous adapt to changing postures and loading conditions. It ensures the
integrity of the spine and provides a stable base for the movements of the
extremities. The core also absorbs forces transmitted through the lower extremity
during activity.
The hip and the lower extremity can be seen as mobile structures but the mobility of
extremity movements depends on the core activity. Core muscles are active before
the initiation of extremity movements. “Proximal stability before distal mobility”.
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9. “Core stability may provide several benefits to the musculoskeletal system, from
maintaining low back health to preventing knee injury” (Willson et al 2005).
Core stability in practice:
1. Lumbo-pelvic-hip complex: good symmetrical mobility and local hip and
pelvic stability.
2. Good muscular balance (in length, tone and strength) in the three
planes:
a. In the sagittal plane:
i. Rectus abdominis m.
ii. Transverse abdominis m.
iii. Erector spinae m.
iv. Multifidus m.
v. Gluteus max. m.
vi. Hamstrings.
vii. Co-contraction of these muscles causes trunk stiffness, raises
the intra-abdominal pressure and provides a stable core.
b. In the frontal plane:
i. Glut med., glut min. m.
ii. Quadratus lumborum m.
iii. Hip adductors.
c. In the transverse plane:
i. Hip rotators.
ii. Trunk rotators
3. Stabilizing corset effect of the thoracolumbar fascia.
Abdominals
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10. Quadratus
lumborum m.
Erector trunci Transverse Gluteus med. &
abdominis m. min. m.
Rectus abdominis
Gluteus max. m.
Adductors
Hamstrings
In the sagittal plane In the frontal plane
Obliquus internus
and externus
Hip rotators
In the horizontal plane
A poor core function/stability can be caused by:
• Lesion in the hip, pelvic and low lumbar joints.
• Muscular weakness and/or disbalance.
• Poor muscular endurance.
• Fatigue.
• Pain/injury – avoidance.
When during activity, the muscles cannot stabilize the spine, pelvis and hips (core),
the patient will be vulnerable for injury.
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11. To illustrate this: it is recently found that patients with paravertebral muscular
dysfunction show increased quadriceps inhibition. (Hart et al 2005).
The osteopath therefore will always evaluate the patients’ core stability by:
• Testing the hip, pelvis and low lumbar joints for harmonious mobility.
• Testing for equal capsuloligamentary tension.
• Testing the muscular balance in the three planes (on length, tone and
strength).
3. Bibliography
Byrne D.P., Mulhall K.J. & Baker J.F. (2010) Anatomy & Biomechanics of the Hip.
The Open Sports Medicine Journal, Vol. 4, pp. 51-57.
Campbell J.D., Higgs R., Wright K. & Leaver-Dunn D. (2001) Pelvis, hip and thigh
injuries. In: Schenck R.C., Guskiewicz K.M., Holmes C.F., Eds. Athletic Training and
Sports Medicine. Rosemount: American Academy of Orthopaedic Surgeons; p. 399.
DonTigny R. (1993) Mechanics and Treatment of the Sacroiliac Joint, The Journal of
Manual and Manipulative Therapy. Vol.1, No. 1, pp. 3-12.
DonTigny R.L. (1994) Function of the Lumbosacroiliac complex as a self-
compensating force couple with a variable, force-depending transverse axis: A
theoretical analysis. The Journal of Manual dz Manipulative Therapy 2: 87-93.
DonTigny R.L. (2005) Critical analysis of the functional dynamics of the sacroiliac
joints as they pertain to normal gait. J of Orthopaedic Medicine (UK) 27:3-10.
DonTigny R.L. (2007) A detailed and critical biomechanical analysis of the sacroiliac
joints and relevant kinesiology. The implications for lumbopelvic function and
dysfunction. In Vleeming A, Mooney V, and Stoeckart R (eds): Movement, Stability &
Lumbopelvic Pain: Integration of Research and Therapy. Churchill Livingstone, 2
edition, Chapter 18, pp 265-278.
Gracovetsky S. (2007) Stability or controlled instability? In Vleeming A, Mooney V,
and Stoeckart R (eds): Movement, Stability & Lumbopelvic Pain: Integration of
Research and Therapy. Churchill Livingstone, 2 edition, Chapter 19, pp 278-294.
Hart D.L., Stobbe T.J., Till C.W. & Plummer R.W. (2005) Effect of Trunc Stabilization
on Quadriceps Muscle Torque. West Virginia University, Morgastown.
Hart J.M., Kerrigan D.C., Fritz J.M., Saliba E.N., Gansneder B. & Ingersoll C.D.
(2005) Contribution of Hamstrings fatigue to quadriceps inhibition following lumbar
extension exercise. Journal of Sports Science and Medicine (2006) 5, 70-79.
Kibler W.B., Press J., & Sciascia A. (2006) The role of core stability in athletic
function. Sports Med, 2006. 36(3): 189-198.
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12. Lee D. et Vleeming A. (2004) The management of pelvic joint pain & dysfunction.
Chapter 34 in Grieves Modern Manual Therapy: The vertebral column. Churchill
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relationship to lower extremity function and injury. J Am Acad Orthop Surg. 13(5):
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