What’s an extraforaminal disc herniation? I understand herniation means the disc has pushed out of its own space between the bones in the spine. What’s the extraforaminal?

Extraforaminal is an anatomic location. The vertebral bones of the spine consist of two main parts. There’s the round bone of the main body. The body is attached by a bridge of bone to the spinal joints (facets) and spinous processes. The spinous process
is what you feel as the back bone through your skin.

Between the main body and the spinous process is a round circle. When the vertebrae are stacked up on top of each other these circles form a canal. The spinal cord passes through this space. It’s called the foramen.

Anything that’s inside the foramen is called intraforaminal. Anything outside the foramen is extraforaminal. A disc that’s extraforaminal has pushed outside of its own space but is not inside the spinal canal. It has probably pushed out more toward the side.

A disc that protrudes straight back can enter the foramen. An intraforaminal disc can put pressure on the spinal cord. An extraforaminal disc is more likely to push to the side and press on the spinal nerve.