S23.3XXA: Sprain of ligaments of thoracic spine, initial encounter
Region: Thoracic injury
By Dr. Daniel Turner, DC · Reviewed September 2, 2026
What does S23.3XXA mean?
S23.3XXA is the ICD-10-CM code for a sprain of the thoracic spine ligaments at the initial encounter, the trauma code for the mid back in collision and lifting injury cases.
Searched as thoracic sprain ICD 10 and mid back sprain diagnosis code.
When does a chiropractor use S23.3XXA?
Completes the three region injury picture on serious collision cases alongside the cervical S13.4XXA and lumbar S33.5XXA sprains. A rear end collision that produces documented findings in all three spinal areas supports all three codes, and together they support the multi region CMT billed during the active phase of the case.
Coding rules that matter
- ✓Seven characters mandatory, with the A, D, S encounter sequence
- ✓Code only regions with documented injury findings; a three sprain claim needs a three region exam
- ✓Thoracic strain of muscle codes separately in the S29 family when documented
The codes around S23.3XXA
| Code | Description |
|---|---|
| S23.3XXA | Thoracic sprain, initial encounter (this code) |
| S23.3XXD | Thoracic sprain, subsequent encounter |
| S23.3XXS | Thoracic sprain, sequela |
| S23.41XA | Sprain of ribs, initial encounter |
| S13.4XXA | Cervical sprain, initial encounter |
| S33.5XXA | Lumbar sprain, initial encounter |
When S23.3XXA is the wrong code
Not a reflexive third member of every collision claim: three regional sprains require three regions of documented findings, and reviewers on PI files count. Rib sprains have their own code at S23.41. Non traumatic mid back pain stays on M54.6.
How does S23.3XXA work on Medicare chiropractic claims?
Secondary behind M99.02 in the rare Medicare trauma claim; in the usual PI context it supports the thoracic portion of multi region CMT and the therapy performed there.
Where claims go wrong
Reflexively coding all three spinal sprains on every collision case regardless of findings; seventh character drift as the case matures.
How Cervica helps with S23.3XXA
Cervica validates diagnosis pointers line by line before a claim goes out, checks the Medicare subluxation pairing and region agreement automatically, and carries diagnoses forward from the SOAP note so the claim always matches what the documentation actually says.
Related codes
Quick answers
What does S23.3XXA mean?
S23.3XXA is the ICD-10-CM code for a sprain of the thoracic spine ligaments at the initial encounter, the trauma code for the mid back in collision and lifting injury cases.
When does a chiropractor use S23.3XXA?
Completes the three region injury picture on serious collision cases alongside the cervical S13.4XXA and lumbar S33.5XXA sprains. A rear end collision that produces documented findings in all three spinal areas supports all three codes, and together they support the multi region CMT billed during the active phase of the case.
How does S23.3XXA work on Medicare chiropractic claims?
Secondary behind M99.02 in the rare Medicare trauma claim; in the usual PI context it supports the thoracic portion of multi region CMT and the therapy performed there.
General information for billing teams, not medical, legal, or coding advice for any individual claim. ICD-10-CM is maintained by CMS and the National Center for Health Statistics; the official code set and guidelines control. Payer policies vary.