RESUMO
INTRODUCTION: Incorrect positioning of the body in space increases the tension of the myofascial tissue and overloads the skeleton. It is important to look for factors that affect the deterioration of body posture that could be eliminated. Understanding the interrelationship between the positioning of individual body segments should be the key knowledge for those involved in the prevention and correction of faulty body posture. The study aimed to determine the relationship between the degree of physiological curvatures of the spine and the incidence of incorrect knee position. MATERIALS AND METHODS: The study involved 685 children aged 10-12. Body height, weight and BMI were measured and calculated. The degree of thoracic kyphosis and lumbar lordosis was assessed using the Zebris Pointer ultrasound system. Valgus and varus knees were diagnosed in an upright position based on the intermalleolar distance with knees together, and intercondylar distance with the feet placed together. The statistical analysis uses descriptive statistics, the Mann-Whitney U test (comparison of girls and boys), the Kruskal-Wallis test, the Tukey's post hoc test (comparison of variables in participants with correct, varus and valgus knees) and Spearman's rank correlation coefficient (the relationship between the position of the spine and knees). RESULTS: The examined girls were heavier than the boys and had higher BMI. Spine deformities and incorrect knee position are common among 10-12-year-old children. The girls and boys differed significantly in the spine shape in the sagittal plane and the intermalleolar distance. Round lumbar lordosis is more characteristic for girls, and for boys, round thoracic kyphosis. For both genders, valgus knees occur more often than varus knees and coexist with decreased thoracic kyphosis. The rounder the thoracic kyphosis, the greater distance between the knees and the smaller distance between ankles. CONCLUSIONS: The frontal knee position significantly correlated with the depth of thoracic kyphosis.