A Vulcan spine and spinal cord
A Borg Queen's spinal cord
The spinal cord was an important part of a living being's nervous system that ran down the spine and transmitted the motor messages from the brain to the rest of the body.
In 2368, Lieutenant Worf was severely injured when a cargo container fell on his back which left him partially paralyzed with a crushed spinal cord. Doctor Toby Russell, a specialist, came aboard to offer assistance. She and Doctor Crusher replaced his spinal cord with a replicated one made using a genetronic replicator. (TNG: "Ethics")
In 2372, Teirna came aboard the USS Voyager with spinal cord trauma, among other injuries. (VOY: "Basics, Part I")
Captain Picard ripped the Borg Queen's metallic spinal cord apart after all her organic substances had been dissolved by plasma coolant in 2373. (Star Trek: First Contact)
The ChoH'a' Species reassignment protocol involved shortening the Klingon spinal cord. (DIS: "Despite Yourself")