Download Gonstead Marking

Gonstead Marking
1-28-99
Marking the X-ray:
1) Put in the dots.
2) Draw lines between the dots.
3) Measure between the lines and the dots.
4) Apply the listing.
Dots: 1 and 2 go at the most superior part of the femur head (both L and R sides).
3 and 4 go at the junction between the last lumbar vertebra and the sacral ala.
(both L and R sides)
5 and 6 go at the most superior portion of the iliac crests (both L and R sides).
7 and 8 go at the most inferior portion of each ischium (both L and R sides).
9 goes at the first sacral tubercle.
10 goes at the center of the symphysis pubis.
Lines:
Use a parallel to draw your lines (find one at any school bookstore).
This parallel needs: A straightedge that goes from 0 to 260 mm.
A center scale that goes from 0 to 80 mm bilaterally.
Rollers that roll smoothly (check this before you pay for it).
1) Connect dots 1 and 2 (= Femur Head Base Line) (FHBL).
2) Roll the parallel up to the most superior of dots 3 and 4.
(staying parallel to the FHBL)
Ideally, you would like to hit both dots 3 and 4 at the same time.
But – one may be inferior (ex – the sacral ala may have dropped)
Draw the line above the inferior of dots 3 and 4.
(at the same level as the more superior dot – for later comparison)
3) Continue rolling up to dots 5 and/or 6.
Draw a line at each one.
All lines should be parallel to each other so far.
Turn the parallel tool upside down and align it with the FHBL.
4) Roll down to dots 7 and 8 and draw 2 lines (one at each side).
Pick a horizontal grid line on the x-ray.
Roll up/down to the most superior femur head.
5) Draw a short line over the more inferior femur head.
This indicates the height of the more superior one.
This will never be parallel to the FHBL.
The lines will diverge laterally and converge medially.
Place the parallel tool perpendicular to the FHBL.
(set the 0 center line on the FHBL).
6) Draw a line from dot 9 down through the center of the sacrum.
Continue this line at the symphysis pubis.
It will either cross: The R pubic bone }
indicates a
The L pubic bone }
possible rotation
Go through dot 10
In an ideal situation, all lines will be parallel or perpendicular to the FHBL.
Keep the parallel tool perpendicular to the FHBL.
Roll it over to the lateral edge of the R ilium.
7) Draw a line at the edge of the R ilium.
Roll the tool medially to the lateral aspect of the R sacral ala.
8) Draw a line at the edge of the R sacral ala (perpendicular to the FHBL).
9) Draw another line at the medial aspect of the R ilium.
Note:
Lines 7 and 8 are parallel to each other.
Repeat lines 7, 8, and 9 for the L ilium.
Align the parallel tool with dots 3 and 4, then draw a line between them.
(= Sacral Base Line) (SBL)
Ideally, the SBL is parallel to the FHBL.
The only lines that may not be parallel or perpendicular to the FHBL are:
The sacral base line
The line at the inferior femur head
Measure:
Place the top edge of the tool on the L iliac crest line.
Measure between the iliac crest and the ischial dot. (= innominate measurement)
Mark it near the ischium.
Repeat for the other side.
Do not confuse the above with __??__.