identify structures 1 to 9 ?
1. Chondrosseous border; 2. Femoral head; 3. Synovial fold; 4. Joint capsule; 5. Labrum; 6. Hyaline cartilage acetabular roof; 7. Bony roof; 8. Lower limb of os ilium; 9. Turning point (bony rim, that is where the concavity turns to convexity).
Describe how the alpha angle as described by Graf is measured?
First, draw the baseline which is the vertical line parallel to either the outer cortex or inner cortex of the ilium. Next, choose the lowest and lateral most point of the bright spot of the lower limb of the os ilium shown as the black dot above marker 8 and using that point draw a line that just tangentially touches bone.
Describe how the beta angle is measured as described by Graf?
The beta angle measures the angle between the base line and the cartilage roof line, which is the line from the turning point shown as a black dot above arrow 9 to the centre of the bright echo of the labrum 5. The three lines in the vast majority of cases do not cross at a single point except in a mature type 1 hip with a sharp bony corner.
USS of the hip using a linear transducer and in a cradle (Sonofix) with probe guide system (Sonoguide).
Anatomical checklist
- Chondrosseous border
- Femoral head
- Synovial fold
- Joint capsule
- Labrum
- Hyaline cartilage acetabular roof
- Bony roof
- Turning point (bony rim, that is where the concavity turns to convexity)
Usability check
- Lower limb - must be visible.
- Plane of ilium - must be vertical (not anterior or posterior).
- Labrum - must be visible.
Measurements
- Alpha angle 60 degrees.
- Beta angle 78 degrees.
Graf type I.