Sent to attorneys August 14, 2026.
Two spine-pain patterns get collapsed in medical records into “the pain is going down the leg, so it must be a pinched nerve.” They are not the same thing, and the distinction changes what the record is actually saying.
Radicular pain arises from irritation or inflammation of a spinal nerve root, the point where a nerve exits the spinal canal. Patients typically describe it as sharp, electric, or lancinating, projected along a narrow band into the arm or leg (roughly a stripe tracing that nerve’s territory). Somatic referred pain arises from deep spinal structures such as the disc annulus, the facet joint, or the supporting ligaments. It is typically deep, dull, and poorly localized, felt in the buttock, groin, or thigh without following a specific nerve distribution. The working definitions most spine physicians use are the ones set out in Bogduk’s 2009 paper in Pain, which the International Association for the Study of Pain has adopted as its terminology. Radiculopathy is a third and separate term: it refers to objective nerve-root dysfunction (weakness, loss of a reflex, sensory loss in a defined dermatome) and can exist with or without pain.
Why this matters for causation analysis. A patient whose only complaint after a rear-end collision is deep, aching buttock or posterior-thigh pain may well have a real injury to a disc or facet joint, but the pain pattern alone does not support a diagnosis of a compressed nerve root, and an MRI showing an incidental disc bulge does not close the loop. Conversely, a patient with true radicular pain in a defined nerve distribution, positive tension signs on examination, and imaging that correlates at the same level presents a much stronger anatomic story. When a treating physician, an IME reviewer, or a records summary uses “radiculopathy,” “radicular pain,” and “referred pain” interchangeably, the causation opinion tends to blur along with the vocabulary. Asking a witness to define the term they used, and to point to the specific examination finding that supports it, usually clarifies more than any additional imaging would.
Medical terms
- Somatic referred pain — pain that comes from a deep body structure (a disc, a joint, a ligament) but is felt in a nearby region such as the buttock, groin, hip, or thigh. “Somatic” simply means “of the body.” The pain generator is at the spine; the brain projects the sensation elsewhere. This is different from pain caused by a compressed or irritated nerve.
- Disc annulus — the tough outer ring of a spinal disc (annulus fibrosus). It surrounds the softer nucleus in the center. Tears or inflammation in the annulus can generate pain on their own, without any nerve being compressed.
- Facet joint — the paired small joints at the back of each spinal level, one on each side. They allow adjacent vertebrae to glide against each other during motion and are a common source of neck and low-back pain after injury.
- Radiculopathy — objective (measurable) dysfunction of a spinal nerve root: weakness in the specific muscles that nerve supplies, loss of a reflex, or numbness in that nerve’s defined skin territory. It is a physical-examination finding, not a description of what the pain feels like.
- Dermatome — the strip of skin whose sensation is served by a single spinal nerve. Numbness that follows a dermatome (rather than the whole leg or a random patch) is a signal that the nerve itself is involved.
Educational only, not case-specific, and not legal or medical advice for any particular matter.
F. Allen Johnston, MD
Louisiana Orthopedic Institute
Baton Rouge
(225) 751-6666 Office
(225) 270-0000 Cell
