Macrae and Wright modified a linear measurement observed by Schober during anterior lumbar flexion.
Procedure:
(1) Have the person stand straight with feet together and arms at the side.
(2) Identify the lumbosacral junction on the midline of the back (point at the intersection of a vertical line through the spine and a horizontal line through the dimples of Venus)
(3) Mark a point 5 cm caudal to the junction.
(4) Mark a second point 10 cm cephalad to the junction.
(5) Measure the distance between these 2 points.
(6) Have the person bend forward, trying to touch toes with the fingertips.
(7) Measure the distance between these 2 points during maximum flexion.
where:
• In the original Schober Index the distance was measured from the lumbosacral junction and not the point 5 cm caudal to it.
index in cm = "distraction on flexion" =
= (distance between the 2 points in cm with maximum flexion) - (distance between the 2 points in cm with the person erect) =
= (distance between the 2 points in cm with maximum flexion) - 15
Interpretation:
• minimum distance: 0
• maximum distance: 11 cm
• According to the data in Macrae and Wright, most adults will have a distance of 7 to 10 cm. According to Jenkinson et al, a normal distance was > 4 cm.
• Ankylosis of the spine prevents flexion, resulting in a short distance.
• A person probably should serve as his/her own control, with reference point measured when lumbar flexion is normal.
• The distance decreases with age and is slightly greater in males.
According to Macrae and Wright (Figure 10, page 587) variation with age is:
distance in cm for a male =
= (8.04 - (0.029 * (age in years))
distance in cm for a female =
= (8.14 - (0.051 * (age in years))
The relationship between flexion of the lumbar spine and distance was given by Macrae and Wright (Figure 6, page 586) as:
skin distance in cm =
= (0.18 * (degrees of lumbar flexion)) + 0.67
This can be rearranged:
degree of lumbar flexion =
= (5.56 * (skin distance in cm)) - 3.72
