2.1 Anatomy, Biomechanics & Kinematics
The body archidecture of the hip joint
The body archidecture of the hip joint
How is the pelvic frontal plane defined?
Describe the relative position of the cardinal pelvic planes.
- Anterior superior iliac spines (ASIS)
- Pubic tubercles
Describe the abduction angles of the acetabulum relative to the cardinal pelvic planes.
Abduction angle = 30-40°
Form Transverse plane to Acetabular axis
Describe the version angles of the acetabulum relative to the cardinal pelvic planes.
version angle = 30-40°
from Frontal plane to Acetabular axis
Describe the Wiburg angles of the acetabulum relative to the cardinal pelvic planes.
Wiburg (W) angle = 30°
From Vertical (parasagittal) axis to Wiburg
Describe the acetabular axis. How is the inlet plane oriented relative to the acetabular axis?
Acetabular axis 30-40° to Transverse AND Frontal plane
What is the purpose of the acetabular labrum?
- more coverage of the femur head
- flexibility of movement
- stability of the joint
Label the two Femoral offset:
- Femoral offset of a VALGUS hip
- Femoral offset of a VARUS hip
What is the "normal" angel of Neck axis to the trans-epicondylar axis?
10°-30° of anteversion
What does the anatomical "teardrop" when viewed radiographically help to identify in the normal acetabulum?
Landmark for
- Kohlers line
- Shentons line
What is the normal CCD (=neck/shaft) angle?
normal CCD = 127°
Which terms can be used to describe deformity where there is a CCD angel
- 112°
- 135°
- coxa vara
- coxa valga
Describe femoral neck offset. How is it defined?
Distance shaft centre to centre of femural head (A)
How does femoral offset change where there is a valgus deformity?
offset decrease
How is could this canal shape?
A - Champagne Flute
How is could this canal shape?
B - Proportional
How is could this canal shape?
C - Stove Pipe
What is canal flare index?
The ration of prox. and distal medullary canal
Describe the three major hip capsular ligaments.
- Iliotrochanteric
- Iliofemoral
- Ischiofemoral
- Pubofemoral
What are the major flexor and extensor muscles of the hip joint?
Flexor:
Iliopsoas
Pectineus
Tensor fascia femoris
Adductor brevis
Sartorius
Extensors
Gluteus maximus
Adductor magnus
What are the internal and external rotator muscles of the hip joint?
Internal
Glutesu medius Gluteus minimus
Tensor fascia femoris
External
Gluteus maximus
Which muscles are responsible for external rotation of the hip joint?
Glutteus maximus
Piriformis
Abductoris longis
etc
Which muscles abduct and adduct the femur at the hip joint?
- Abductor brevis, longus, magnus
- Gluteus masimus, medius, minimus
Describe seven types of motion that occur at the hip joint.
- Extension
- Flexion
- Aduction
- Abduction
- Internal rotation
- External rotation
- Circumduction
Describe the role of the IT (iliotibial) band and abductor muscles in balancing the forces on the neck of the femur.
Lateral comression forces are further increased by the action of the abductor and rotator muscles, which balance the plevis.
How can the system of forces operating around the hip joints in the two-leg stance be described?
see picture
What is the joint reaction force?
The sum of body weight and muscle force
How does joint reaction force change when the body leans away from the supporting hip?
(The body weight moment arm is increased in length.)
There is a significant increase in the angle and magnitude of the resultant JRF (joint reaction force
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How is the pelvic frontal plane defined?
Describe the relative position of the cardinal pelvic planes.
- Anterior superior iliac spines (ASIS)
- Pubic tubercles
Describe the abduction angles of the acetabulum relative to the cardinal pelvic planes.
Abduction angle = 30-40°
Form Transverse plane to Acetabular axis
Describe the version angles of the acetabulum relative to the cardinal pelvic planes.
version angle = 30-40°
from Frontal plane to Acetabular axis
Describe the Wiburg angles of the acetabulum relative to the cardinal pelvic planes.
Wiburg (W) angle = 30°
From Vertical (parasagittal) axis to Wiburg
Describe the acetabular axis. How is the inlet plane oriented relative to the acetabular axis?
Acetabular axis 30-40° to Transverse AND Frontal plane
What is the purpose of the acetabular labrum?
- more coverage of the femur head
- flexibility of movement
- stability of the joint
Label the two Femoral offset:
- Femoral offset of a VALGUS hip
- Femoral offset of a VARUS hip
What is the "normal" angel of Neck axis to the trans-epicondylar axis?
10°-30° of anteversion
What does the anatomical "teardrop" when viewed radiographically help to identify in the normal acetabulum?
Landmark for
- Kohlers line
- Shentons line
What is the normal CCD (=neck/shaft) angle?
normal CCD = 127°
Which terms can be used to describe deformity where there is a CCD angel
- 112°
- 135°
- coxa vara
- coxa valga
Describe femoral neck offset. How is it defined?
Distance shaft centre to centre of femural head (A)
How does femoral offset change where there is a valgus deformity?
offset decrease
How is could this canal shape?
A - Champagne Flute
How is could this canal shape?
B - Proportional
How is could this canal shape?
C - Stove Pipe
What is canal flare index?
The ration of prox. and distal medullary canal
Describe the three major hip capsular ligaments.
- Iliotrochanteric
- Iliofemoral
- Ischiofemoral
- Pubofemoral
What are the major flexor and extensor muscles of the hip joint?
Flexor:
Iliopsoas
Pectineus
Tensor fascia femoris
Adductor brevis
Sartorius
Extensors
Gluteus maximus
Adductor magnus
What are the internal and external rotator muscles of the hip joint?
Internal
Glutesu medius Gluteus minimus
Tensor fascia femoris
External
Gluteus maximus
Which muscles are responsible for external rotation of the hip joint?
Glutteus maximus
Piriformis
Abductoris longis
etc
Which muscles abduct and adduct the femur at the hip joint?
- Abductor brevis, longus, magnus
- Gluteus masimus, medius, minimus
Describe seven types of motion that occur at the hip joint.
- Extension
- Flexion
- Aduction
- Abduction
- Internal rotation
- External rotation
- Circumduction
Describe the role of the IT (iliotibial) band and abductor muscles in balancing the forces on the neck of the femur.
Lateral comression forces are further increased by the action of the abductor and rotator muscles, which balance the plevis.
How can the system of forces operating around the hip joints in the two-leg stance be described?
see picture
What is the joint reaction force?
The sum of body weight and muscle force
How does joint reaction force change when the body leans away from the supporting hip?
(The body weight moment arm is increased in length.)
There is a significant increase in the angle and magnitude of the resultant JRF (joint reaction force
