Definitions

backbone

backbone

[bak-bohn]
backbone: see spinal column.
or spinal column or spine or backbone

Flexible column extending the length of the torso. In humans, it consists of 32–34 vertebrae, with different shapes and functions in each of five regions: 7 cervical, in the neck (including the atlas and axis, modified for free movement of the skull); 12 thoracic, in the chest; 5 lumbar, in the lower back; 5 sacral (fused into the sacrum, part of the pelvic girdle); and 3 to 5 coccygeal (vestigial tailbones fused into the coccyx). The body of each vertebra is separated from its neighbours by cushioning intervertebral disks of cartilage. Behind the body is a Y-shaped vertebral (neural) arch with structures extending up and down to form joints with the adjacent vertebrae and to the back and sides to provide attachment points for muscles and ligaments. The spine supports the torso and protects the spinal cord.

Learn more about vertebral column with a free trial on Britannica.com.

Backbone may mean:

Search another word or see backboneon Dictionary | Thesaurus |Spanish
Copyright © 2014 Dictionary.com, LLC. All rights reserved.
  • Please Login or Sign Up to use the Recent Searches feature