Kinesiology of the Musculoskeletal System Chapter 12

1
Kinesiology of the Musculoskeletal
SystemChapter 12

• The Hip

2
Anatomical Structures of the Hip

• Acetabulum
• Acetabular labrum
• Articular cartilage
• Femoral head
• Joint capsule and ligaments
• Ligamentum teres
• Hip musculature

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Acetabulum
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Femoral Angle of Inclination

• Angle of Inclination angle within the frontal
  plane between the femoral neck and the medial
  side of the femoral shaft
• Average adult measurement of 125 degrees
• Newborns born with 140-150 degree angle which
  reduces to approximately 125 degrees with onset
  of standing/walking
• Coxa Vara A of I markedly less than 125 degrees
• Coxa Valga A of I markedly greater than 125
  degrees

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Angle of Inclination
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Femoral Torsion Angle

• Torsion angle relative rotation (twist) that
  exists between the shaft and neck of the femur
• Average adult measurement of 10-15 degrees of
  anterior rotation (Anteversion) of femoral head
• Newborn TA typically 30 degrees of anteversion
  which reduces to 10-15 degrees by 6 years of age

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Femoral Torsion Angle (cont.)

• Normal Anteversion 10-15 degrees allows optimal
  alignment and joint congruency
• Excessive Anteversion TA significantly greater
  than 15 degrees
• Often associated with congenital dislocation in
  the infant marked joint incongruence and
  increased degenerative wear
• Compensated excessive anteversion may result in
  toeing-in gait pattern (pigeon toed)
• Retroversion TA significantly less than 15
  degrees (i.e. 5 degrees of anteversion)
• Less common than excessive anteversion

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Excessive Femoral Anteversion
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Hip Joint Capsule Ligaments
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Hip Labrum and Articular Cartilage

• Acetabular labrum fibrocartilage extension of
  acetabulum adds depth and stability to the joint
• Articular cartilage maximal thicknesses of
  acetabular and femoral articular cartilage is
  aligned at their superior-anterior aspects
• Maximal joint reactive forces and pressures seen
  at the superior-anterior aspect of the acetabulum
• Joint pressure increases 3X at mid stance phase
  of walking due to transfer of weight and IMA of
  ipsilateral pelvic stabilizing abductor muscle
  group

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Hip Capsule and Ligaments

• Hip joint capsule reinforced externally with
  tough capsular ligaments
• Capsule lined internally with synovial membrane
• Ligaments and capsules are secondary joint
  stabilizers
• Normal capsule and
• ligaments limit
• extreme hip ROM
• pathological tightness
• may limit normal
• functional hip joint
• ROM

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Hip Capsule and Ligaments (cont.)

• Iliofemoral ligament -one of the thickest and
  strongest in the body can effectively prevent
  extreme hip extension can support body weight in
  pathological conditions such as Cerebral Palsy

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Closed Pack Position of the Hip

• CPP unique position of the hip joint where the
  articular surface is most congruent and the
  ligaments are maximally taut
• Full passive hip extension coupled with slight
  internal rotation and abduction maximally
  stretches the capsule and maintains congruency
• Passive hip flexion coupled with internal
  rotation and abduction stretches the capsule but
  is moving away from joint congruency this is a
  common pathological capsular pattern

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Osteokinematics of the Hip
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Femoral on Pelvic Motion

• F on P Motion occurs when hip joint action occurs
  as a result of the femur moving on a relatively
  fixed or stationary pelvis
• F on P motion can be closed or open chain
  movement
• Closed Chain i.e. Squat Stance phase of gait
• Open Chain Standing hip extension exercise
  Swing phase of gait

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Femoral on Pelvic Motion (cont.)

• Passive hip flexion limited to 80-90 degrees by
  hamstrings when knee is extended otherwise to
  120 degrees
• Passive hip extension is to 20 degrees with an
  extended knee or to approximately 0 degrees with
  fully flexed knee due to rectus femoris tightness

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Femoral on Pelvic Motion (cont.)

• Abduction is to 40 degrees limited by capsular
  ligaments, adductor and hamstring muscles
• Adduction limited to about 25 degrees due to
  interference from other limb, and/or due to
  abductor muscles, iliotibial band or hip capsule
• Internal Rotation is to about 35 degrees
• External Rotation is to about 45 degrees may be
  limited by hip capsule, iliotibial band or tensor
  fascia latae muscle

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Femoral on Pelvic Motion
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Lumbopelvic Rhythm

• LPR the kinematic relationship between the
  lumbar spine and hip joints during sagittal plane
  movement
• Ipsi-directional LPR when pelvis and lumbar
  spine move in same direction useful for
  activities such as extending the reaching
  capacity of the upper extremities
• Contra-directional LPR when the pelvis and the
  lumbar spine move in opposite directions seen in
  walking, dancing, or any other activity in which
  the position of the supralumbar trunk must be
  held fixed

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Lumbopelvic Rhythm
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Pelvic on Femoral MovementFlexion/Extension

• Standing Flexion limited to 80-90 degrees
  ipsi-directional LPR
• Standing Extension limited to about 20 deg
  contra directional LPR
• Pelvic tilt anterior or posterior movement of
  the pelvis (reference point on iliac crest) on
  stationary femoral heads, offset by
  contra-directional LPR

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Contra-Directional Lumbopelvic RhythmPelvic Tilt
Anterior Posterior
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Pelvic on Femoral Motion
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Pelvic on Femoral MovementAbduction/Adduction

• Abduction active hip hiking of opposite
  hip/pelvis via contra directional LPR limited to
  30 degrees by lumbar spine ROM
• Adduction accomplished through lowering of
  opposite hip/pelvis via contra directional LPR
  total adduction determined by lateral myofascial
  elements in non-pathological hip rather than by
  lumbar spine ROM

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Pelvic on Femoral MovementInternal/External
Rotation

• Internal Rotation forward rotation (anterior)
  of opposite hip/pelvis in the horizontal plane
• External Rotation backward (posterior) of
  opposite hip/pelvis in the horizontal plane
• P on F Rotation on a relatively stationary trunk
  is limited by lumbar spine rotational limitations
• If the lumbar spine rotation accompanies hip
  rotation, hip rotation becomes limited by hip
  joint capsular or boney limitations

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Hip Muscle Groups

• Hip Flexors
• Primary iliopsoas, rectus femoris, TFL,
  sartorius, adductor longus, pectineus
• Hip Adductors
• Primary Adductor longus, brevis magnus,
  pectineus, gracilis
• Hip Internal Rotators
• Primary gluteus medius minimus, TFL

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Hip Muscle Groups (cont.)

• Hip Extensors
• Primary gluteus maximus, hamstrings
• Hip Abductors
• Primary gluteus medius minimus, TFL
• Hip External Rotators
• Primary gluteus maximus, piriformis, deep
  external rotator muscles

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Lumbopelvic Stabilization
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P on F F on P Adduction
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Dual Action of Muscles
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P on F Hip Abduction and Pelvic Stabilization
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Hip Abductors Pelvic Stabilization

• Poor pelvic stabilization can occur as a result
  of functionally weak hip abductor muscles or as
  a result of underlying pathology (muscular
  dystrophy, hip arthritis, hip instability).
• Trendelenburg sign dropping of the opposite hip
  and pelvis upon single leg support indicates
  poor pelvic stabilization does not identify
  cause of instability
• May be compensated for by leaning over the
  unstable hip

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Trendelenburg Sign
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Posterior Pelvic Tilt
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P o F External Hip Rotation
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Hip External Rotators
Gluteus Maximus
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P on F External Rotation
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References

• Neumann, D. Kinesiology of the Musculoskeletal
  System. 2002. Human Kinetics.
• www.rad.washington.edu/atlas