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The backbone can be divided into five regions, starting with the uppermost, or cervical region, which normally has seven vertebrae. Next down is the thoracic (chest) section, normally with12 vertebrae. From each vertebra a rib extends to curl protectively around the chest area. Usually, the top ten ribs come all the way around the trunk and attach to the breast-bone (or sternum); but the bottom two ribs do not reach the breastbone and thus called floating ribs. The thoracic section also must support the shoulder gridle, consisting of collarbones (clavicles) and shoulder blades (scapulas). At the end of each shoulder blade is a shoulder joint - actually three distinct joints working together - where the arm connects to the axial skeleton.
Below the thoracic vertebrae come the five vertebrae of lumbar section. This area gets a good deal of blame for miseries: lower back pain often occurs around the area where the bottom thoracic vertebra joins the top lumbar vertebra. Furthermore, the lumbar region or small of the back is also a well-know site of back pain; indeed, from the word "lumbar" comes lumbago, medically an imprecise term, but popularly used to describe very real back pain.
Below the lumbar region are two vertebrae so completely different from the 24 above them - and even from each other- that it seems strange they are called vertebrae at all: the sacrum and the coccyx. These two vertebrae are both made up of several distinct vertebrae that are present at birth. The sacrum is a large bone that was once five vertebrae. The coccyx was originally four vertebrae- and, incidentally, is all that remains of man's tail in his evolution from primates.
Below the thoracic vertebrae come the five vertebrae of lumbar section. This area gets a good deal of blame for miseries: lower back pain often occurs around the area where the bottom thoracic vertebra joins the top lumbar vertebra. Furthermore, the lumbar region or small of the back is also a well-know site of back pain; indeed, from the word "lumbar" comes lumbago, medically an imprecise term, but popularly used to describe very real back pain.
Below the lumbar region are two vertebrae so completely different from the 24 above them - and even from each other- that it seems strange they are called vertebrae at all: the sacrum and the coccyx. These two vertebrae are both made up of several distinct vertebrae that are present at birth. The sacrum is a large bone that was once five vertebrae. The coccyx was originally four vertebrae- and, incidentally, is all that remains of man's tail in his evolution from primates.
Labels: the backbone
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