An image of the severed spinal columns of a murderd Tok'ra symbiote and its host.
Spine refers to the Vertebral Column (also known as the backbone) in all Vertebrae lifeforms. In Human anatomy the spine this divided into three segments: the cervical vertebrae, the thoracic vertebrae and the lumbar vertebrae. Symbiotes attached themselves at the base of the Brain and the top of the spine. (SG1: "The Enemy Within")
A Wraith tracking device can branch out and fuse to a runner's spine and brain stem. (SGA: "Tracker")