THE SPINAL COLUMN

THE SPINE 

    Your spine is the central support system for your entire body, assisting with nearly all movement, while supporting and protecting your spinal cord. It must be firm enough to support your body weight when standing, yet flexible and strong enough to anchor your body while helping your upper and lower limbs to move smoothly.

THE SPINAL COLUMN

    Your spine is a column of up to 34 bones called vertebrae. All but 10 of these vertebrae are movable and they are divided into three groups: seven cervical (neck), 12 thoracic (midback), and five lumbar (lower back). 

    The remaining 10 vertebrae are located at the base of the spine; five of these are fused together to form a triangular-shaped bone—the sacrum—which sits between your two iliac bones to form your pelvis. 

    Below this there are three to five (most people have four) fused or partially mobile segments that form your coccyx, the rudimentary “tail” inherited from early human ancestors.

    Your spine is a column of up to 34 bones called vertebrae. All but 10 of these vertebrae are movable and they are divided into three groups: seven cervical (neck), 12 thoracic (midback), and five lumbar (lower back). 

    Each of the 12 thoracic vertebrae of the midback is joined to a rib on either side, with the resulting rib cage surrounding and protecting your heart, lungs, and liver. When you inhale fully, the thoracic spine extends slightly as the ribs rise; when you exhale, the thoracic spine flexes. When you twist your upper body, it rotates around your thoracic spine.

    When you are upright—during most of your waking hours—the five lumbar vertebrae bear the bulk of your weight and provide a flexible link between the upper and lower parts of your body.

    Below the five lumbar vertebrae, the five sacral vertebrae fuse together to form a bone called the sacrum. This bone is noticeably different in men and women, with a man’s sacrum being longer and narrower than a woman’s. 

    The sacral vertebrae are connected to the vertebrae at the end of the spine—known as the coccygeal vertebrae—by a joint called the sacrococcygeal symphysis. Together, the coccygeal vertebrae form the coccyx, or tail bone.