Guilan university of medical sciences
Hip Joint
By
Dr Kamran Ezzati PT, PhD
Associate Professor
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Reference 1
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Reference 2
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Six short m: obturator internus and externus, the gemellus superior and
inferior, the quadratus femoris, and the piriformis
Posterior fibers of the gluteus med& mini. & max.
The piriformis and gluteus max are the only two muscles that cross the
SI joint
Effective joint compressors because their combined action line parallels
the head and neck of the femur.
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obturator internus, like the gluteal muscles, decreased its moment arm
for lateral rotation with increased hip flexion
The piriformis; large moment arm for lateral rotation with the hip joint at
0° but switched to a medial rotator with half the moment arm when the
hip reached 90° of flexion.
The obturator externus and quadratus femoris: only lateral rotators that
did not diminish their moment arm for lateral rotation with increased hip
joint flexion
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Tonic stabilizers of the joint
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There are no muscles with a primary function of producing
medial rotation of the hip joint.
Anterior portion of the gluteus med.& mini.& TFL muscles,
adductor muscles exception of the gracilis
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Both hips are in neutral or slight hyperextension.
The gravitational extension moment is largely checked: by
capsuloligamentous structures, although slight or intermittent activity in
the iliopsoas.
In the frontal plane during bilateral stance, the upper incumbent
body weight is transmitted through the sacroiliac joints and pelvis to the
right and left femoral heads.
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The gravitational moment arms for
the right hip (DR) and the left hip
(DL) are equal.
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The pelvis is maintained in equilibrium in the frontal plane without the
assistance of active muscles
Joint compression across each hip in bilateral stance was 80% to 100%
of body weight, rather than one third (33%) of body weight, as
commonly proposed: capsuloligamentous Tension and The slight activity
in the iliopsoas muscle
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Thus, in bilateral stance when both lower limbs bear at least some of the
superimposed weight, the contralateral abductors and adductors may
function as synergists to control the frontal plane motion of the pelvis.
In unilateral stance, activity of the adductors either in the weight-bearing
or non-weightbearing hip cannot contribute to stability of the stance limb.
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Right hip joint compression body weight [2/3 W] +
[1/6 W]
Right hip joint compression body weight 5/6 W
[1/6 W= the non-weightbearing limb]
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A subject with weighs 825 N, HAT accounts for 550 N.
One lower extremity weighs one sixth of body weight, or 137.5 N.
Therefore,
When this individual lifts one leg off the ground, the supporting hip
joint will undergo 687.5 N (or five sixths of body weight) of compression 6
from body weight alone.
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The force of gravity acting on HAT and the nonweightbearing left lower
limb (HATLL) will create an adduction torque around the weight-bearing
hip joint; that is, gravity will attempt to drop the pelvis.
Joint compression or a joint reaction force that is a
combination of both body weight and abductor muscular
compression.
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If there is a need to reduce the torque of gravity in unilateral stance and
if body weight cannot be reduced, the moment arm of the gravitational
force can be reduced by laterally leaning the trunk over the pelvis
toward the side of pain or weakness when in unilateral stance on the
painful limb.
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Does not increase the joint
compression caused by
body weight. However, it does
reduce the gravitational
torque.
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Some of the weight of HATLL would follow the arm to the cane,
Some one can push down on a cane with approximately 15% of his body
weight.
The total hip joint compression when the cane is used ipsilaterally is still
greater, however, than the total joint compression of 1,031.25 N found
with a compensatory lateral trunk lean
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it is not as effective in reducing hip joint compression as the undesirable
lateral lean of the trunk (some benefits in energy expenditure
and structural stress reduction)
Moving the cane to the opposite hand produces substantially different
and better results.
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The reduction in the magnitude of HATLL is the same as
it is when the cane is used on the same side(15%)
The cane is now in a position to assist the abductor muscles in
providing a countertorque to the torque of gravity
45% reduction in gluteus medius EMG, not an elimination of
activity
75% reduction in force that the classic calculation
An equivalent contraction of the latissimus dorsi muscle
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Femoroacetabular Impingement
1. Cam impingement
2. Pincer impingement
Labral Pathology
Arthrosis
Fracture
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Cam impingement
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Pincer impingement
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