The cross dominancy and structural disorders of head and vertebral column

The cross dominancy (CD) implicates as a condition that dominant eye and dominant hand are situated in opposite sides of a body. This condition can produce malformation and structural disorders in head posture and vertebral column. The aim of this study was to investigate the relationship between CD and structural disorders in vertebral column and head posture in students of Zahedan University of Medical Sciences. In this cross-sectional study, 300 students of Zahedan University of Medical Sciences were randomly selected and their dominant eye was determined by Miles test. Then subjects were divided into two groups (with cross dominancy and unilateral dominancy). The presence of malformations of vertebral column and head posture were determined by checker board and plumb line. The data were analyzed using descriptive and analytical (Chi square) statistical tests. The results of the present study demonstrated that 76 out of 300 students (25.3%) had cross dominancy (CD). There were a significant difference between CD and scoliosis (P<0.001) or shoulder un-leveling (P=0.03) in two groups, but not between forward head posture (P=0.10) and chin deviation (P=0.22) with CD in two groups. The scoliosis and shoulder un-leveling had higher prevalence in CD subjects that is due to weak muscular support of vertebral column in coronal plane, but because of strong muscular support of vertebral column in sagittal plane, CD had not any considerable effect on chin deviation and forward head posture