The four parts of the spine are the cervical spine, the thoracic spine, the lumbar spine and the sacrum. These areas stretch from the neck down to the coccyx, or tailbone.
The cervical spine is made up of seven vertebrae, commonly known as C1 to C7. This part of the spine is located in the neck.
The thoracic spine is in the upper back. It is composed of the 12 thoracic vertebrae, T1 to T12. These vertebrae attach to the ribs and sternum and are generally very stable.
The lumbar spine is in the lower back and normally contains five vertebrae, L1 to L5. This part of the spine allows the most motion and carries the most weight, which is why lower back problems are the most common.
The sacral region is made up of five bony segments, S1 to S5, and is situated below the lumbar region. These segments together create a triangular bone that serves as the base of the spine.