Hip Flashcards
Pubis makes up _____ of the acetabulum in what direction?
25% anterior
Describe the incomplete inferior rim of acetabulum
Acetabular notch, spanned by transverse acetabular ligament
Abnormally shallow acetabulum that leads to lack of fem head coverage
Acetabular dysplasi
Center edge angle for dysplasia
<16 degrees
Normal center edge angle
> 35 degrees
Implications of acetabular anteversion
Unstable hip
Implications of acetabular retroversion
Can lead to over-coverage, impingement between acetabulum and femoral head
Fibrocartilaginous ring that deepens the acetabulum
Labrum
4 roles of labrum
- Stability
- Increases contact area
- Decreases stress
- Allows mobility
Two ways to describe femoral shape
- Angle of inclination
2. Angle of torsion
Define angle of inclination
Frontal plane angle between femoral neck and shaft
Normal angle of inclination
125 degrees
Increase in angle of inclination
Coxa valga
Decrease in angle of inclination
Coxa vara
Define angle of torsion
Relative rotation between the neck and shaft in the transverse plane
Describe femoral anteversion and retroversion
Anteversion: femoral neck positioned more anteriorly relative to shaft
Retroversion: neck positioned more posteriorly relative to shaft
Normal femoral anteversion angle
15 degrees
How will someone with femoral anteversion compensate?
Pigeon toed
How will someone with femoral retroversion compensate?
Duck walk
What kind of forces are present at femoral neck?
Bending
Are greater/lesser trochs in capsule?
No
Define how much mobility we have at the hip
Ligaments
Function of iliofemoral lig
Resists hip extension, IR and ER
Pubofemoral lig role
Resists extension and abduction, ER
Ischiofemoral lig rol
Resists IR and extension, superior fibers resist adduction
Close packed position of the hip
Full extension, slight IR and abduction
Elongates capsule
Open packed position of the hip
30 degrees flexion, slight abduction and ER
Most congruent position of hip
90 degrees flexion with slight abduction and ER
Posterior pelvic tilt can contribute to _____ of the L/S
Flexion
Anterior pelvic tilt contributes to ______ of the L/S
Apparent extension
Trunk side bend and frontal plane pelvic motion contributes to _____________ of hip
Apparent abduction
What movement of the hip is mostly spin?
Flexion/extension
Direction of spin during flex/ext
Flexion: posterior
Extension: anterior
LOG in double limb stance
Just posterior to M-L axis for flex/ext
Reasoning behind lateral trunk lean
Brings LOG closer to hip joint AOR
5 ways to tear labrum
- Trauma
- Instability
- Dysplasia
- FAI
- Degeneration
Anterior pelvic tilt force couple
Iliopsoas, erector spinae
Posterior pelvic tilt force couple
Abdominals, hamstrings
Controls forward lean of body
Pelvic-on-femoral hip extension
Flexed position increases extensor torque gen from
Glut max, adductors, hams
Why is glut max quiet in standing?
The HAT weight extends the hip
Important role of adductors
Stabilizing pelvis during weight shifting from one limb to the other
When do abductors produce greatest torque?
Slight add or neutral position
When do IRs create greatest torque?
When hip is flexed to 90 degrees
When is external rotation most evident?
During pelvic-on-femur rotation - planting and cutting maneuver
