A sprain is an injury to a ligament, the tissue that connects bone to bone. A strain is an injury to a muscle or tendon, the tissue that moves the bone. After a car accident, the two words are often used as if they meant the same thing. They do not, they are coded separately, and the difference affects what can be tested and documented. A collision can cause both. This is how I separate them for patients in Charlotte.
The Definitions
The American Academy of Orthopaedic Surgeons defines a sprain as a stretch or tear of a ligament (AAOS OrthoInfo). The National Institute of Arthritis and Musculoskeletal and Skin Diseases defines a strain as an injury to either a muscle or a tendon (NIAMS). In the spine, the ligaments are the disc annulus, the longitudinal ligaments, the ligamentum flavum, the interspinous, supraspinous, and intertransverse ligaments, and the facet joint capsules. The muscles are the paraspinal and neck muscles that move and brace the spine.
How They Are Coded
The diagnosis codes used in the United States keep the two apart. In ICD-10-CM, S13.4 is sprain of ligaments of the cervical spine, and S16.1 is strain of muscle, fascia, and tendon at neck level (ICD-10-CM). The sprain category carries a note excluding the muscle strain code, so the two are separate diagnoses that can be coded together when both are present. The thoracic and lumbar ligament sprains have their own codes, S23.3 and S33.5. A record that codes only a strain has not documented a ligament injury.
Why the Distinction Matters
Ligament and muscle injuries behave differently. Panjabi's hypothesis of chronic back pain rests on subfailure injury to ligaments and the mechanoreceptors inside them, and he cited the poor healing capacity of spinal ligaments as part of why such injuries could persist (Panjabi, Eur Spine J 2006). That is a hypothesis, but the laboratory evidence for ligament injury in whiplash is real. In cadaver spines exposed to a simulated rear impact, the facet capsular ligaments elongated more than controls under load (Ivancic, Clin Biomech 2008). In living patients with chronic neck pain after whiplash, placebo-controlled blocks confirmed the facet joints, which those capsules surround, as the pain source in 60% (Lord, Spine 1996).
The two injuries are also tested differently. A ligament injury that allows excessive motion can be measured on flexion and extension X-rays against the AMA Guides thresholds. A muscle strain cannot be measured that way. It is diagnosed from the history and exam.
What the Exam Can and Cannot Tell
On exam, sprains and strains overlap. Both cause pain, limited motion, tenderness, and muscle guarding. I am not aware of a validated hands-on test that reliably separates a cervical ligament sprain from a muscle strain. That is why the record should say what was tested. If motion films were taken and measured, the result belongs in the chart. If they were not, the chart should not imply a ligament injury was excluded.
Why Both Are Common After a Crash
A collision loads the ligaments and the muscles at the same moment. A patient can have a strain that recovers in weeks and a ligament injury that does not. Treating every post-crash neck as a strain, or every one as a sprain, misses the patients who have the other injury or both.
For an example of how post-collision imaging findings and outcomes are documented in the peer-reviewed literature, read Dr. Justin Dick's published case report on refractory lumbar pain following a motor vehicle accident in a geriatric patient.
Frequently Asked Questions
What is the difference between a sprain and a strain?
A sprain is a stretch or tear of a ligament, which connects bone to bone (AAOS). A strain is an injury to a muscle or tendon (NIAMS). A car accident can cause both.
What is the ICD-10 code for a neck sprain versus a neck strain?
In ICD-10-CM, S13.4 is sprain of ligaments of the cervical spine and S16.1 is strain of muscle, fascia, and tendon at neck level. They are separate diagnoses.
Is whiplash a sprain or a strain?
It can be either or both. ICD-10-CM lists whiplash injury of the cervical spine under S13.4, the ligament sprain code, but a collision can also strain the neck muscles.
Can a spinal sprain be seen on X-ray?
A ligament sprain that allows excessive motion can be measured on flexion and extension X-rays against AMA Guides thresholds. A muscle strain cannot be measured on X-ray.
Why does it matter whether my injury is called a sprain or a strain?
Ligament and muscle injuries are coded, tested, and documented differently. Dr. Justin Dick in Charlotte, NC records which tissues were tested so the chart does not imply a ligament injury was excluded when it was not examined.
Where can I get a neck sprain or strain evaluated after a car accident in Charlotte, NC?
Dr. Justin Dick, DC, CNMT, ARRT(N)(CT), evaluates neck sprains and strains at Clear Life Scoliosis and Chiropractic Center, 8814 Rachel Freeman Way, Suite 103, Charlotte, NC 28278, phone 980-368-0766. Personal injury patients are treated on a lien basis, with no out-of-pocket payment at the time of care.
Sources and Evidence Tiers
- American Academy of Orthopaedic Surgeons. Sprains, Strains, and Other Soft-Tissue Injuries. OrthoInfo. LinkEvidence tier: Professional society patient education (expert opinion)
- National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health. Sprains and Strains (patient information booklet).Evidence tier: Government patient education (expert opinion)
- Centers for Disease Control and Prevention, National Center for Health Statistics. ICD-10-CM: codes S13.4 (sprain of ligaments of cervical spine), S16.1 (strain of muscle, fascia and tendon at neck level), S23.3, and S33.5.Evidence tier: Official classification system
- Panjabi MM. A hypothesis of chronic back pain: ligament subfailure injuries lead to muscle control dysfunction. Eur Spine J. 2006;15(5):668-676. PMID 16047209. LinkEvidence tier: Hypothesis paper (mechanistic reasoning)
- Ivancic PC, Ito S, Tominaga Y, et al. Whiplash causes increased laxity of cervical capsular ligament. Clin Biomech. 2008;23(2):159-165. PMID 17959284. LinkEvidence tier: Cadaveric laboratory study (mechanistic)
- Lord SM, Barnsley L, Wallis BJ, Bogduk N. Chronic cervical zygapophysial joint pain after whiplash: a placebo-controlled prevalence study. Spine. 1996;21(15):1737-1744. PMID 8855458. LinkEvidence tier: Placebo-controlled diagnostic prevalence study (68 patients)
- American Medical Association. Guides to the Evaluation of Permanent Impairment, Fourth, Fifth, and Sixth Editions.Evidence tier: Expert consensus (impairment rating guideline)
About the author. Dr. Justin M. Dick, DC, is the owner and treating clinician at Clear Life Scoliosis and Chiropractic Center in Charlotte, NC. He holds dual imaging credentials as a Certified Nuclear Medicine Technologist (CNMT) and as an ARRT-registered technologist in nuclear medicine and CT, ARRT(N)(CT). He is a Senior Fellow of the CLEAR Institute, holds the ISICO World Masters credential, is a SOSORT provisional member, and is a certified DOT medical examiner on the FMCSA National Registry. He has multiple peer-reviewed publications indexed in PubMed and serves as adjunct faculty at Life, Sherman, and Palmer chiropractic colleges.
Service Area
Clear Life Scoliosis and Chiropractic Center sees personal injury and spinal imaging patients from Charlotte NC, Huntersville NC, Ballantyne NC, Matthews NC, Concord NC, Mooresville NC, Rock Hill SC, and Fort Mill SC.
Related Pages
- Personal injury and car accident spinal care in Charlotte
- Dr. Justin Dick's research
- Case report: refractory lumbar pain after a motor vehicle accident
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Clear Life Scoliosis and Chiropractic Center
8814 Rachel Freeman Way, Suite 103
Charlotte, NC 28278
Phone: 980-368-0766
Email: office@clearlifescoliosis.com
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