The spinal cord
Spinal cord · medulla spinalis
A finger-thick cable of nerves running down your back that links your brain to your body.
What it does
The spinal cord runs from the base of the brain down the canal inside the vertebrae, ending at about the level of the first lumbar vertebra. It carries signals both ways between brain and body and contains its own circuits for reflexes, such as pulling your hand back from something hot before you feel the pain.
Surprising fact
In adults the spinal cord stops around the top of the lower back; below that, a bundle of nerve roots called the cauda equina, Latin for "horse's tail", fills the canal.
Why it matters
Because the cord ends higher than the spine, doctors can safely insert a needle into the lower back to sample spinal fluid or give an epidural.
Nearby
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Sources
Drafted with AI help; awaiting a human fact-check against these sources.
Open in the 3D atlas · Suggest a correction · Not medical advice.
3D models: Z-Anatomy & BodyParts3D (CC BY-SA 4.0 / 2.1 JP). Card text CC BY 4.0.