Reliability and Validity of Measurement of Infrasternal Angle by Radiographic Methods

The thorax consists of a relatively rigid rib cage, formed by the ribs, thoracic vertebrae, and sternum.1 It encloses the thoracic cavity, forming a protective cage for the cardiopulmonary organs, and supports attachment of the diaphragm and trunk muscles such as the internal or external oblique muscles.2-4 Changes in the alignment of the thorax has a variety of causes, including congenital chest wall deformities such as pectus excavatum/carinatum and spine deformities such as osteoporosis with excessive kyphosis or scoliosis.2,5-8 Asymmetrical lengths of the internal and external oblique muscles between the right and left sides also affect thorax alignment.9 In addition, asymmetrical length or activation of the abdominal oblique muscle can cause movement impairment syndrome such as thoracic rotation syndrome or lumbar rotation syndrome.10,11 One method used to evaluate thorax alignment is to measure the infrasternal angle, which requires measuring Reliability and Validity of Measurement of Infrasternal Angle by Radiographic Methods