Normal axial relationship
Baseline view before herniation: the posterior disc margin stays behind the thecal sac, with clear lateral recess and foraminal corridors.
Reference anatomy view — the only labeled diagram.Pain drawing
Show where it hurts.
Draw your symptoms on a simple body picture — pick an area, mark where it aches, burns, or feels numb, then tap Complete. We'll point to the one nerve root that pattern most often fits, in plain language, as a starting point for a conversation with a clinician.
Takes about a minute · nothing is saved
Learn by spine region
Reference pages for clinicians — disc levels, nerve roots, dermatomes, motor and reflex findings.
Educational tool only. Use as a pattern-recognition aid and correlate with the exam, imaging, and red flags.
Cervical · Upper-extremity pattern aid
Cervical disc level → exiting root.
In the cervical spine, disc-level naming maps differently than lumbar levels: a C5–C6 disc lesion most classically affects the C6 root, a C6–C7 lesion affects C7, and C7–T1 affects C8.
Selected cervical level
C6–C7
Affected root
C7
exiting cervical root
Dermatome (sensory)
Myotome (motor)
Reflex
Bedside clue
Dermatomal map
C7 highlighted
Cervical upper-extremity zones
| Disc level | Classic root | Dermatome | Motor | Reflex | Common mimic / caution |
|---|
Cervical clinical warning
- C7 is often reported as the most frequently involved cervical nerve root, while C2–C4 radiculopathy is uncommon [Kang et al.].
- Classic patterns are imperfect: McAnany et al. found standard textbook pain/numbness patterns in only 54% of 239 single-level surgical cases, with nonstandard patterns differing by an average of 1.68 dermatomal levels [McAnany et al.].
- Screen for myelopathy when symptoms include hand clumsiness, gait imbalance, hyperreflexia, Babinski, clonus, Hoffmann sign, or bowel/bladder change; signs or symptoms of myelopathy warrant urgent referral [McCartney et al.].
Cervical root patterns synthesize Kang et al., McCartney et al., and the Merck Manual.
Thoracic · Chest and abdominal wall pattern aid
Thoracic level → band-like pattern.
Thoracic radiculopathy is usually a sensory-predominant syndrome: burning, shooting, or band-like pain wrapping from the back toward the chest or abdomen. Routine limb reflexes are usually less useful than the sensory stripe and myelopathy screen.
Selected thoracic level
T8–T9
Pattern root
T8
thoracic band
Dermatome / band
Motor / trunk wall
Reflex
Mimic / caution
Dermatomal map
T8 highlighted
Thoracic band landmarks
| Disc level | Root pattern | Dermatome landmark | Motor / reflex expectation | Key caution |
|---|
Thoracic clinical warning
- Thoracic radiculopathy is the least common radiculopathy location, and symptoms often wrap around the front of the body in a dermatomal distribution [Johns Hopkins].
- The most common presenting complaint is band-like chest wall pain; sensory loss may be asymmetric and dermatomal, while motor findings are often limited to intercostal or abdominal wall weakness [PM&R KnowledgeNow].
- Thoracic and abdominal pain can mimic many visceral, rib, zoster, diabetic, infectious, or neoplastic conditions, and diagnosis may be delayed for months or years [Choi et al.].
- Screen carefully for thoracic myelopathy. Bowel or bladder dysfunction, hyperreflexia, profound weakness, gait change, or a clear sensory level should prompt urgent evaluation [PM&R KnowledgeNow].
Thoracic mapping uses common dermatome landmarks and synthesis from PM&R KnowledgeNow, Johns Hopkins Medicine, and StatPearls — Spinal Nerves.
Lumbar/Sacral · Lower-extremity pattern aid
Lumbar disc level → nerve root deficit.
Select a disc level and herniation morphology. The tool returns the most likely affected root with its dermatome, myotome, reflex, and bedside clue.
Approximately 95% of lumbar disc herniations occur at L4–L5 or L5–S1 [StatPearls].
Selected level
L4–L5
Affected root
L5
paracentral · traversing
Dermatome (sensory)
Myotome (motor)
Reflex
Bedside clue
Dermatomal map
L5 highlighted
Lumbosacral sensory zones
Morphology atlas · Axial schematic
Disc shape changes which root is at risk.
These simplified axial views show where the fragment sits relative to the canal, lateral recess, and neural foramen. They are teaching schematics, not diagnostic MRI criteria.
Central / broad-based
Midline posterior material narrows the canal. Symptoms may be bilateral or multiroot rather than a clean single-root pattern.
Use caution: not a one-to-one root localizer.
Paracentral / posterolateral
The fragment sits medial to the foramen and most often contacts the traversing root.
Example: L4–L5 usually affects L5.
Foraminal
The fragment sits within the neural foramen and most often contacts the exiting root.
Example: L4–L5 usually affects L4.
Extraforaminal / far-lateral
The fragment sits lateral to the foramen and most often contacts the exiting root beyond the canal.
Example: L4–L5 usually affects L4.Traversing-versus-exiting root rules follow StatPearls — Lumbar Disc Herniation.
Comparison matrix
All five disc levels, both morphologies. Tap a row to load it in the tool above.
| Disc level | Paracentral → traversing root | Far-lateral → exiting root | Dermatome (autonomous zone) | Motor | Reflex |
|---|
Autonomous zones from StatPearls — Radicular Back Pain. Motor and reflex columns synthesize StatPearls — Lumbar Disc Herniation and the Merck Manual.
Clinical warning · Not a diagnosis
Read the output as a pattern, not a localizer.
- Treat this tool as a pattern-recognition aid for trainees and clinicians, not a standalone localizer or substitute for examination, imaging, and clinical judgment.
- Root functions overlap, particularly the L2–L4 group sharing anterior-thigh innervation, hip flexion, hip adduction, and knee extension. Muscle strength is often preserved because most muscles receive multi-root innervation [StatPearls — Radicular Back Pain].
- Pain commonly does not follow textbook dermatomes. Murphy et al. found 64.1% of lumbar radicular pain patterns were non-dermatomal overall (L5 83.7%, L4 71.4%, L3 69.2%, L2 60.0%); only S1 was predominantly dermatomal at 64.9% [Murphy et al.].
- Isolated sensory, motor, or reflex findings have imperfect accuracy. A BMC systematic review reported sensory testing sensitivity 0.61 / specificity 0.63, motor sensitivity 0.13–0.61, and reflex specificity up to 0.93 but sensitivity 0.14–0.67. The authors recommend consolidating findings rather than relying on a single test [Tawa et al.].
- Disc morphology determines which root is compressed: paracentral and posterolateral lesions usually affect the traversing root, while far-lateral and extraforaminal lesions usually affect the exiting root [StatPearls].
- Imaging is not diagnostic in isolation: roughly 27% of asymptomatic adults have disc herniation on MRI [StatPearls — Radicular Back Pain]. Correlate with history, exam, and red flags.
- Urgent evaluation is warranted for progressive weakness, bowel or bladder dysfunction, saddle anesthesia, or any concern for cauda equina syndrome.
Pain drawing
Where do your symptoms travel?
Pick an arm, torso, or leg area to draw symptoms that radiate from the spine — like pain, numbness, or tingling. Pick the area that bothers you most; you can mark more than one.
An education tool for clinic discussion. It does not diagnose the cause of symptoms, and nothing you draw is saved.
Region
Paint your symptoms
Press and drag to paint over the spots where you feel it, like drawing with your finger. Use the eraser, undo, or clear in the tool palette to fix mistakes.
Brush
Your result
Here's the nerve pattern your drawing most likely matches
Each nerve from your spine sends feeling to its own area of skin and muscle. Based on where you marked your symptoms, here's the nerve area that may fit best. Nerve areas overlap a lot, so think of this as a helpful starting point for a talk with your care team — not a diagnosis.
Body map
No root selected
The area of skin this nerve usually covers
Please keep in mind
Nerves share a lot of the same skin and muscles, and real symptoms do not always follow the textbook. This is here to help you and your care team talk things through — it is not a diagnosis, and it does not replace a real exam.
- Get medical care right away if you have new or fast-worsening weakness, trouble walking or keeping your balance, numbness in the groin or saddle area (where you sit), or any loss of control over your bladder or bowels.
- If you feel symptoms on both sides of your body, or in several separate areas, the cause may be something other than a single pinched nerve.
References
Sources
- StatPearls — Lumbar Disc HerniationDisc-morphology rules, level-specific deficits, ~95% L4–L5/L5–S1 prevalence.
- StatPearls — Radicular Back PainAutonomous zones, L2–L4 functional overlap, asymptomatic-MRI caveat.
- Merck Manual — Nerve Root DisordersLevel-specific sensorimotor patterns and reflex changes.
- Murphy DR et al. — Pain patterns and descriptions in patients with radicular painNon-dermatomal frequency by level (overall 64.1%).
- Tawa N et al. — BMC Musculoskeletal Disorders systematic reviewDiagnostic accuracy of clinical tests for lumbar radiculopathy.
- Kang KC et al. — Cervical Radiculopathy Focus on Characteristics and Differential DiagnosisCervical root patterns, common levels, prevalence, provocative-test and diagnostic caveats.
- McCartney S et al. — Cervical radiculopathy and cervical myelopathyC5–C8 key neurologic findings and myelopathy red flags.
- McAnany SJ et al. — Observed patterns of cervical radiculopathyNonstandard cervical radicular pattern frequency in single-level surgical cases.
- PM&R KnowledgeNow — Thoracic Radiculopathy/MyelopathyThoracic presentation, band-like pain, sensory findings, motor limitations, and myelopathy red flags.
- Johns Hopkins Medicine — RadiculopathyThoracic radiculopathy as least common location with dermatomal wrapping pain/numbness.
- StatPearls — Neuroanatomy, Spinal NervesThoracic spinal nerve anatomy, dermatomes, and thoracic/abdominal wall innervation.
- Ralf Stephan / Wikimedia Commons — Dermatoms.svgHuman anterior/posterior dermatome map asset used as the built-in anatomical reference; public domain.
- Choi HE et al. — Thoracic Radiculopathy due to Rare CausesThoracic radiculopathy diagnostic delay, mimicry, and frequent lack of motor deficit.
