The hollow or portion of the covering member which connects the boards.
The bones, muscles, tendons and other tissues that reach from the base of the skull to the tailbone. The spine encloses the spinal cord and the fluid surrounding the spinal cord. Also called backbone, spinal column and vertebral column.
Spine has been defined 5 different ways in documents like USPC Consolidated Glossary, Glossary of Cancer Terms, Glossary of Printing Terms, and 2 more.