**2.1 Examinee sample**

This research includes N = 1105 school age children, of which 528 students were from urban areas (261 girl and 267 boys) and 577 students from rural areas (281 girl and 296 boys). They attended 11 elementary schools in the Sarajevo Canton and the surrounding area, and their average age was M = 82.864. Students who were from first to fifth grade were tested in every school. The breakdown of students included:


### **2.2 Variable sample**

In order to determine the spinal status, the following variable was used: the method of measuring the curvature of the spine based on Napoleon Wolanski's criteria from 1975, *D-5 spine posture (ESP)—Evaluation of spine posture*. To determine the spinal status, it was necessary for the examinee to turn his back to the examiner with slightly separated but parallel feet in his normal posture. All of the examinees were in their underwear in rooms where the temperature was from 20 to 23°C.

The description of the measuring instrument—evaluation of spinal posture:

0—Physiological curve: normal and within the sagittal and frontal plane.

1—First-degree deviation: kyphosis, scoliosis, and lordosis.

2—Deviation of some kind: a specific deformity or combination of deformities but on a second-degree level

#### **2.3 Data-processing methods**

The analysis of spinal deformities of students in school was done by using the descriptive chi-square statistics. Applying the descriptive statistics, the researchers could determine the numerical and percentage frequency of the spinal deformity. These are displayed in tables and graphs.
