Radiculopathy Imaging Correlation¶
Definition¶
Radiculopathy is dysfunction of a spinal nerve root causing pain, weakness, numbness, or reflex changes in the distribution of that nerve root. Imaging plays a critical role in identifying the structural cause and determining whether surgical intervention is indicated.
Cervical Radiculopathy — Level Correlation¶
In the cervical spine, the nerve root exits above the same-numbered pedicle (except C8):
| Root | Disc Level | Motor | Sensory | Reflex |
|---|---|---|---|---|
| C5 | C4-5 | Deltoid, biceps | Lateral arm | Biceps |
| C6 | C5-6 | Wrist extensors, biceps | Lateral forearm, thumb | Brachioradialis |
| C7 | C6-7 | Triceps, wrist flexors | Middle finger | Triceps |
| C8 | C7-T1 | Hand intrinsics, grip | Medial forearm, ring/little finger | — |
Lumbar Radiculopathy — Level Correlation¶
In the lumbar spine, the nerve root exits below the same-numbered pedicle:
| Root | Disc Level | Motor | Sensory | Reflex |
|---|---|---|---|---|
| L4 | L3-4 | Quadriceps (knee extension) | Medial leg | Knee jerk |
| L5 | L4-5 | Dorsiflexion (foot drop), great toe extension | Lateral leg, dorsal foot | — |
| S1 | L5-S1 | Plantarflexion, eversion | Lateral foot, sole | Ankle jerk |
Imaging Correlation¶
- Paracentral disc herniation — Compresses the traversing root (e.g., L4-5 paracentral herniation compresses L5)
- Foraminal disc herniation — Compresses the exiting root (e.g., L4-5 foraminal herniation compresses L4)
- Far lateral disc herniation — Also compresses the exiting root
Clinical Pearl
The exiting vs traversing nerve root concept is critical for surgical planning. At L4-5: a paracentral herniation compresses the L5 (traversing) root, while a foraminal herniation compresses the L4 (exiting) root. Matching the clinical dermatomal and myotomal findings to the correct nerve root and then to the correct disc level and herniation location is the fundamental task of spine imaging correlation.
Key Points¶
- Cervical roots exit above the same-numbered pedicle; lumbar roots exit below
- Paracentral herniations compress the traversing root; foraminal herniations compress the exiting root
- Clinical-imaging correlation (matching symptoms to specific root to specific structural cause) is the cornerstone of spine radiology
- The image findings must match the clinical presentation to be clinically significant
References¶
- Margetis K, Magnus W, Mesfin FB. Cervical Radiculopathy. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing. Available from: https://www.ncbi.nlm.nih.gov/books/NBK441828/
- Alexander CE, Weisbrod LJ, Varacallo MA. Lumbosacral Radiculopathy. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing. Available from: https://www.ncbi.nlm.nih.gov/books/NBK430837/
- Dydyk AM, Khan MZ, Singh P. Radicular Back Pain. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing. Available from: https://www.ncbi.nlm.nih.gov/books/NBK546593/
- Expert Panel on Neurological Imaging; Hutchins TA, Peckham M, Shah LM, Parsons MS, et al. ACR Appropriateness Criteria® Low Back Pain: 2021 Update. J Am Coll Radiol. 2021;18(11S):S361-S379. Available from: https://pubmed.ncbi.nlm.nih.gov/34794594/
- Expert Panel on Neurological Imaging; Eldaya RW, Parsons MS, Hutchins TA, et al. ACR Appropriateness Criteria® Cervical Pain or Cervical Radiculopathy: 2024 Update. J Am Coll Radiol. 2025;22(5S):S136-S162. Available from: https://pubmed.ncbi.nlm.nih.gov/40409873/
- Berry JA, Elia C, Saini HS, Miulli DE. A Review of Lumbar Radiculopathy, Diagnosis, and Treatment. Cureus. 2019;11(10):e5934. Available from: https://pmc.ncbi.nlm.nih.gov/articles/PMC6858271/
- Kang KC, Lee HS, Lee JH. Cervical Radiculopathy Focus on Characteristics and Differential Diagnosis. Asian Spine J. 2020;14(6):921-930. Available from: https://pmc.ncbi.nlm.nih.gov/articles/PMC7788378/
- Soltani ZR, Sajadi S, Tavana B. A comparison of magnetic resonance imaging with electrodiagnostic findings in the evaluation of clinical radiculopathy: a cross-sectional study. Eur Spine J. 2014;23(4):916-921. Available from: https://pmc.ncbi.nlm.nih.gov/articles/PMC3960424/
- Radiopaedia. Lumbar disc disease. Available from: https://radiopaedia.org/articles/lumbar-disc-disease