SUMMARY. Interactions between thoracic spine posture and mobility are believed to play a role in the development of spinal pain syndromes. Accordingly, appropriate and effective manual therapy management is dependent on a sound knowledge of the anatomy and biomechanics of this region of the vertebral column. This paper reviews the primary anatomical influences on thoracic posture, mobility and stability. The consequences of anatomical variation and degenerative change, their effect on thoracic kyphosis, and the range and patterns of thoracic movement, are examined. The implications for assessment and management of thoracic spine dysfunction are discussed together with some considerations for the application of manual therapy treatment. Copyright 1997 Harcourt Publishers Ltd.