Osteokinematics: Sagittal Plane Motions of the femur at

the hip joint

Flexion: 90o-135o

Extension: 0o-30o

Role of 2 joint muscles?

Osteokinematics: Frontal Plane Motions of the femur at

the hip joint

Abduction: 30o-50o

Adduction: 10o-30o

Role of 2 joint muscles?

Osteokinematics: Transverse Plane Motions of the femur at

the hip jointIR (extension*): 35o-45o

(Luttgens & Hamilton)IR (flexion**): 30o-45o

ER (extension*): 45o-50o

(Luttgens & Hamilton)ER (flexion**): 45o-60o

*Extension = Neutral -Terminal **Flexion = 900

Osteokinematicmotions of the femur at the hip joint during functional activities

*

**

D. Neumann – Kinesiology of the MS System

Hip Arthrokinematics

Osteokinematics: Sagittal plane Motions of the Pelvis at the Hip Joint

Osteokinematics: Frontal plane Motions of the Pelvis at the Hip Joint

Osteokinematics: Transverse Plane Motions of the Pelvis at the Hip Joint

Open Kinematic Chain Motions: LumboPelvic Rhythm

Closed Kinematic Chain MotionsThe system now strives

to keep the head & trunk upright

lumbar spine & pelvis motion will now generally be opposite of that during lumbar-pelvic rhythm

Acetabular Spatial OrientationFaces laterallyFaces anteriorly

18.5o males21.5o women

Faces inferiorly22o - 42o range38o in males35o in females

3 Acetabular Changes With Aging:

Ossification of the articulation of the three bones of the pelvisincreased “central stability”

Decreased acetabular “roundness”reduced co-aptation

Increased Central Edge Angleincreased superior stability

Structure of the Proximal FemurFemoral Head

more spherical than

acetabulum

fovea capitis

Spatial Orientation

Structure of the Proximal Femur: Angle of ?

Angle of InclinationFrontal plane angulation b/t the

shaft & neck of femurContributes to the normal

valgus position of the kneeDecreases with age

150o early infancy125o in adults120o in elderly

Abnormal Femoral Inclination Angle

Coxa ValgaIncrease leg length produces hip adductionIncrease “pre load” to hip abductorsDecrease moment arm of abductors

Coxa Vara leg length

Relative hip abduction

Poor hip abductor length tension relationship

Impingement may limit abduction ROM

Stress concentration superior contact area

Coxa Vara: congenital, developmental or traumatic

Structure of the Proximal Femur: Angle of ?

>15o Angle of Torsion or Version: Anteversion or Medial Femoral Torsion

Abnormal Angles of VersionEckoff DG: Orth Cl NA: 1994

Femoral anteversion decreases with ageBut if anteversion is excessive at birth it will

generally persist throughout lifetime

Excessive AnteversionIf uncompensated anteversion will expose significant amount of femoral head anteriorly

Excessive Anteversion

In order to improve congruency of joint surfaces lower extremity internal rotation may occur.

This may result in occur in “toed in” posture & gait.

Abnormal Angles of Version

If angle of version is less than 15o: Retroversion or Lateral Femoral Torsion

<15o Angle of Torsion or Version: Retroversion or Lateral Femoral Torsion

RetroversionIf uncompensated may

expose excessive head of femur posteriorly

To improve congruency, the LE may externally rotate and appear “toed out”

Position of Greatest Hip Congruency?

Combined position of:flexionabductionlateral rotation

Frequently used position for post hip dislocation immobilization

High compressive loads may be necessary to achieve maximum congruency

Is this closed pack position?

Position of Maximum Hip Congruency: Impact on Ligamentous Tension

Hip flexion, lateral rotation & abduction tends to “uncoil” supporting hip ligaments

Hip ligaments are tightened by extension

Frontal Plane Spatial Orientation of Hip and Stability?

Inferior angulation of acetabulum < the superior angulation of the femoral neck.

Therefore, a significant portion of the head remains uncovered.

This may lead to superior stability.

IliopsoasPsoas major is attached

to anterior lumbar vertebra

Iliacus is attached to iliac fossa

Tension within this group will group will “pull” lumbar curvature anteriorly increasing lumbar lordosis

Tensor Fascia Lata

Flexes & internally rotates hip Abducts if the hip is already

flexed Influence of the Thomas testMost important contribution of

TFL is maintaining tension in the ITB

Tensor Fascia LataITB is considered to assist in

relieving the femur of some of the tensile loads on the shaft.

TFL (along with gluteus max) has a roll in “taking up the slack” in the ITB to enhance this function

Possible role in muscle imbalances at hip

Gluteus mediusAsynchronous function of three parts

anteriormiddleposterior

All fibers abductAnt. fibers flex & IRPost. fibers extend & ERPossible role in muscle imbalances at

the hipTrochanteric Bursa

AdductorsPeak isometric

torque exceeds that of abductors

Attachment to pubic ramus may be clinically significant.

Gracilis is the only adductor to cross the knee

Medial Hip RotatorsThere is no muscle with a primary

function of hip medial rotation Muscles with lines of pull anterior to

the hip joint axis at some point of the ROM may contribute to the activity

TFL & anterior gluteus medius may be the most significant of these.

Unilateral Stance Ipsilateral Trunk List

Ipsilateral Cane Contralateral Cane

Impact of a Carried Load: Contralateral Upper Extremity

EMG of hip abductor muscles increased16.8% at 5% BW load38.9% at 10% BW

load58.4% at 15% BW

loadNeumann D, PT 76: 1320-1330, 1996

EMG of hip abductor muscles decreased10.6% at 5% BW

load16.9% at 10% BW

load17% at 15% BW

loadNeumann D, PT 76: 1320-1330, 1996

Impact of a Carried Load: Ipsilateral Upper Extremity