Tragus-to-wall distance (TWD) measurements is a method to evaluate spinal mobility in ankylosing spondylitis (AS) patients and it also takes place in Bath Ankylosing Spondylitis Metrology Index (BASMI). Being obese or slim may affect TWD. As well as the person's losing or taking weight may lead wrong evaluations, in comparative studies, according to the height or weight uneven distribution of groups may affect the results. The aim of this study is to investigate whether the body shape affect TWD or not.

Healthy volunteers between 18-65 ages who have no disorder that may disturb posture or erect position (inflammatory diseases, kyphosis, scoliosis, joint deformities)will be included into the study. A wall corner will be used as the measurement platform; the evaluated person will be positioned as described in BASMI. A rigid ruler will be placed form anterior superior iliac spine (SIAS) to the lateral wall, parallel to the back wall; a projection point will be determined and its distance from back wall will be measured (SIAS-WD). In the same position, projection point of the middle of the humerus head and back wall distance (shoulder-WD) and TWD also will be measured. The relationships between these parameters will be statistically assessed.

Inclusion Criteria:

• Volunteers between 18-65 ages

Exclusion Criteria:

• subjects with disorders that may disturb posture or erect position
• inflammatory diseases,
• kyphosis,
• scoliosis,
• joint deformities

healthy subjects between 18-65 ages who have no disorder that may disturb posture or erect position (inflammatory diseases, kyphosis, scoliosis, joint deformities)