Paracentral vs Far Lateral Disc Herniation, Explained — Ryan Sauber, MD

Name: Central, Paracentral, Foraminal, and Far Lateral Disc Herniations | Ryan Sauber, MD
Creator: Ryan Sauber, MD

Reviewed by Ryan Sauber, MD · Fellowship Director, AHN Orthopaedic Spine Fellowship · Last reviewed October 2026

MRI reports describe a disc herniation by where it sits: central, paracentral, foraminal, or far lateral (also called extraforaminal). The difference is how far the piece of disc has moved from the middle of the spine toward the side. That location matters because it determines which nerve gets pinched. A paracentral herniation at L4-L5 usually presses on the L5 nerve, while a foraminal or far lateral herniation at the same level presses on L4.

This page explains the four zones in plain terms, what each one tends to feel like, and why the location changes the surgical approach. The basics of what a herniated disc is and how it's treated are on the herniated disc page.

The four zones

Picture the disc from above, with the spinal canal behind it. Moving from the middle outward:

Central: straight back into the middle of the spinal canal.
Paracentral: just off center, toward one side of the canal. Reports may also call this posterolateral or subarticular. It's the most common location.
Foraminal: inside the foramen, the side tunnel where a nerve exits the spine.
Far lateral, or extraforaminal: past the foramen, outside the spine entirely. This is the least common of the four.

Diagram of a lumbar disc seen from above, showing the central, paracentral, foraminal, and far lateral zones along the back of the disc, with the dural sac, the traversing L5 nerves, and the exiting L4 nerves. — The four zones, seen from above at the L4-L5 disc.

Which nerve gets pinched

At every level of the low back, two nerves are near the disc. One is passing by on its way down to exit at the next level (the traversing nerve). The other is leaving the spine right at that level (the exiting nerve). Location decides which one is in the way.

Using L4-L5 as the example: central and paracentral herniations usually hit the traversing L5 nerve. Foraminal and far lateral herniations hit the exiting L4 nerve. That one-level shift explains why two people with an "L4-L5 herniation" can have pain in completely different parts of the leg.

Two diagrams of the L4-L5 disc. Left: a paracentral herniation pressing on the traversing L5 nerve inside the spinal canal. Right: a far lateral herniation outside the spine pressing on the exiting L4 nerve. — Same level, different nerve: a paracentral herniation pinches L5, a far lateral herniation pinches L4.

Typical patterns, using L4-L5 as the example. Individual anatomy varies.
Location	Nerve usually affected	Where symptoms tend to go	Usual surgical route, if needed
Central	L5, sometimes on both sides; a large one can press on several nerves	Back pain, sometimes one or both legs	From the back, between the laminae
Paracentral	L5 (traversing)	Down one leg, outer calf, top of the foot, big toe	From the back, between the laminae (interlaminar)
Foraminal	L4 (exiting)	Front of the thigh, inner shin, sometimes knee weakness	From the side, through the foramen (transforaminal)
Far lateral	L4 (exiting)	Same as foraminal, often quite intense	From the side (transforaminal), or a muscle-splitting approach

How each one tends to feel

Paracentral herniations produce classic sciatica: pain running down the back or side of one leg, often into the foot, sometimes with numbness or weakness in the foot or toes.

Central herniations more often cause back pain, and leg symptoms can be on one side, both sides, or neither. A large central herniation can compress several nerves at once. Numbness in the groin or buttocks, or any change in bladder or bowel control, needs same-day evaluation.

Foraminal and far lateral herniations pinch the nerve in a tighter space, where it has less room to move away. Pain is often severe, and at L4-L5 or L3-L4 it tends to show up in the front of the thigh rather than the back of the leg. People are sometimes worked up for a hip or knee problem first. More detail is on the far lateral disc herniation page.

Two diagrams of the L4-L5 disc. Left: a central herniation pushing into the dural sac. Right: a foraminal herniation pressing on the exiting L4 nerve. — A central herniation pushes on the dural sac. A foraminal herniation pinches the exiting nerve in a tight space.

Does location change treatment?

For non-surgical care, mostly no. Physical therapy, anti-inflammatory medication, and time help all four types, and most herniations improve without surgery. One difference: for foraminal and far lateral herniations, an injection placed right at the foramen (transforaminal) tends to reach the irritated nerve better than a standard epidural.

For surgery, location changes a lot. Central and paracentral herniations are reached from the back, between the laminae, either with an endoscope or a microscope. Foraminal and far lateral herniations sit off to the side, where the standard approach from the back doesn't reach well. A transforaminal endoscopic approach goes in from the side through the foramen, right where those herniations are. That match between the herniation and the route is one of the clearer advantages of endoscopic spine surgery, covered on the endoscopic spine surgery page.

Diagram of a lumbar vertebra from above with two arrows: an interlaminar route from the back between the laminae into the spinal canal, and a transforaminal route from the side through the foramen to the disc. — The interlaminar route comes in from the back. The transforaminal route comes in from the side, through the foramen.

Reading your own MRI report

Reports don't always use the same words. "Posterolateral" and "subarticular" usually mean paracentral. "Extraforaminal" means far lateral. "Foraminal zone" means inside the foramen. A report may also describe a herniation as spanning two zones, such as "paracentral and foraminal." The level (L4-L5, for example) plus the zone tells you which nerve is most likely involved. There is more on report language on the foraminal narrowing on your MRI page.

Common questions

What is the difference between a paracentral and a far lateral disc herniation?

A paracentral herniation sits just off center inside the spinal canal and usually pinches the nerve that continues down to the next level. A far lateral herniation sits outside the spine, past the foramen, and pinches the nerve exiting at that level. At L4-L5, that means L5 for paracentral and L4 for far lateral.

Is a central disc herniation worse than a lateral one?

Not necessarily. Most central herniations behave like any other and improve with time. The concern with a large central herniation is that it can press on several nerves at once, so numbness in the groin or buttocks or a change in bladder or bowel control needs urgent evaluation. Lateral herniations are often more painful because the nerve is trapped in a tighter space.

Why does my L4-L5 herniation cause pain in the front of my thigh?

Most likely because it is foraminal or far lateral. Those herniations pinch the L4 nerve, which runs to the front of the thigh and inner shin. A paracentral L4-L5 herniation would usually pinch L5 instead, sending pain down the outer calf to the top of the foot.

How common are far lateral disc herniations?

They are the least common type, roughly 5 to 10 percent of lumbar disc herniations. Paracentral herniations are by far the most common.

What does posterolateral mean on an MRI report?

It usually means the same thing as paracentral: the herniation has pushed backward and slightly to one side, into the edge of the spinal canal.

Do far lateral herniations heal without surgery?

Many do. Their natural history is broadly similar to other disc herniations, and a large share improve over weeks to months. A transforaminal injection can help calm the nerve while that happens.

Talking it through

Endoscopic spine surgery is the focus of my practice, and matching the approach to where the herniation actually sits is a big part of that. If your MRI describes a herniation and you want to understand what its location means for you, I'd be glad to go over the images at an appointment.

Central, paracentral, foraminal, and far lateral disc herniations