You may find many conflicting instructions on locating this site. Some sources claim that Suprailiac, Iliac Crest, Supraspinale, Suprailium and Iliocristale are different sites. Other people say that they all refer to the same site. Another opinion is that this is the same site, but the technique changed from measuring on the side of the body to halfway toward the front.
It does not matter much where exactly you measure this skinfold, because all body fat calculation methods give you only an approximate result.
What matters is whether your measurements are consistent or not. For consistency you should always measure exactly the same spot on your body. If you measure skinfolds consistently, the graphs will show the true dynamic of your body fat.
You may google Suprailiac and chose the description that is clear to you and that allows you to repeatably locate the same spot. There are also hundreds of YouTube clips
The subject should be standing with weight evenly distributed and feet together.
1. Mark the spot (it is also used for waist circumference measurement).
Palpate the right hip to find the upper edge of the pelvis (ilium). It may help to work your way up the pelvis from the front of the hip. Using the cosmetic pencil, draw a horizontal line just above the uppermost edge of the pelvis. Cross this mark at the imaginary line from the armpit down the side of the torso.
2. Pinch the skin. Place your thumb on the intersecting marks and place your index finger above the mark and toward the front of the body. The skinfold should slope downward at approximately a 45 degree angle toward the pubic area.
3. Apply the caliper jaws approximately two centimeters below the fingertips.
General rules: taking skinfold measurements.