The spine (vertebral column) is located between the base of the skull and coccyx. The ‘back’ usually refers to the area between the spinous process of the 7th cervical vertebra and the coccyx. The term ‘neck’ is reserved for the area between the base of the skull (occipital bone or C0) and T1.
The spine plays a large role in determining body posture. In addition, the spine protects the spinal cord and the cauda equina, and serves as a point of attachment for many muscles of the shoulder and pelvic girdle.
The cervical part is the most agile, whereas the thoracic part is the least agile. The large shoulder muscles attach at the cervicothoracic transition. The lumbar spine is an attachment point for important flexors in the hip joint and carries a large part of the body weight.