2026 ICD-10-CM Diagnosis Code S23.3XXASprain of ligaments of thoracic spine, initial encounter

ICD-10-CM Codes›S00–T88›S20-S29›S23

ICD-10-CM S23.3XXA
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

S23.3XXA is a billable ICD-10-CM diagnosis code for sprain of ligaments of thoracic spine, initial encounter. The 7th character A marks it as an initial encounter code, used while the patient is receiving active treatment. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 551 through 552, 963 through 965. Coders also document this condition as sprain of spinal ligament. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Sprains and strains, initial encounter.

Code Identity

ICD-10-CM Code
S23.3XXA
Billable Status
Yes — Valid for Submission
Code Describes
Sprain of ligaments of thoracic spine, initial encounter
Short Description
Sprain of ligaments of thoracic spine, initial encounter
Same as the full description in the CMS dataset.
Parent Code
S23.3
Sprain of ligaments of thoracic spine

Code Classification

ChapterS00–T88Injury, poisoning and certain other consequences of external causes
SectionS20-S29Injuries to the thorax
CategoryS23Dislocation and sprain of joints and ligaments of thorax
This CodeS23.3XXASprain of ligaments of thoracic spine, initial encounter

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Sprain of spinal ligament
  • Thoracic back sprain

Coding GuidelinesGuidance

The appropriate 7th character is to be added to each code from block Dislocation and sprain of joints and ligaments of thorax (S23). Use the following options for the applicable episode of care:

  • A - initial encounter
  • D - subsequent encounter
  • S - sequela

Source: ICD-10-CM Official Guidelines for Coding and Reporting, FY 2026, published by CMS and the National Center for Health Statistics.

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR INJ024
Sprains and strains, initial encounter
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Spine Injuries and Disorders

Your backbone, or spine, is made up of 26 bone discs called vertebrae. The vertebrae protect your spinal cord and allow you to stand and bend. A number of problems can change the structure of the spine or damage the vertebrae and surrounding tissue. They include:

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert S23.3XXA to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
847.1 Sprain thoracic region
Approximate The match is approximate rather than exact.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About S23.3XXAOverview

Is S23.3XXA (Sprain of ligaments of thoracic spine) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report sprain of ligaments of thoracic spine, initial encounter on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What does the 7th character A in S23.3XXA mean?

The final character A marks the initial encounter: use it while the patient is receiving active treatment for sprain of ligaments of thoracic spine, such as an emergency visit or first evaluation.

What MS-DRG does S23.3XXA group to?

When sprain of ligaments of thoracic spine, initial encounter is the principal diagnosis on an inpatient stay, it groups to MS-DRG 551, 552, 963, 964, 965, with relative weights from 0.9405 to 2.7338 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of S23.3XXA?

Under the General Equivalence Mappings, sprain of ligaments of thoracic spine, initial encounter converts to ICD-9-CM 847.1 (sprain thoracic region). The mapping is approximate, so confirm the match fits the documentation.

Footnotes

[1] Not chronic - A diagnosis code that does not fit the criteria for chronic condition (duration, ongoing medical treatment, and limitations) is considered not chronic. Some codes designated as not chronic are acute conditions. Other diagnosis codes that indicate a possible chronic condition, but for which the duration of the illness is not specified in the code description (i.e., we do not know the condition has lasted 12 months or longer) also are considered not chronic.