T1

The first thoracic vertebra (T1) is the first vertebra of the thoracic region, located between the seventh cervical vertebra (C7) and the second thoracic vertebra (T2).

In vertebrates, thoracic vertebrae form the region of the vertebral column associated with the rib cage and bear articular surfaces for ribs. T1 marks the transition between the cervical and thoracic regions of the vertebral column.