S16.1XXA: Strain of muscle, fascia and tendon at neck level, initial encounter
Region: Cervical injury
By Dr. Daniel Turner, DC · Reviewed September 2, 2026
What does S16.1XXA mean?
S16.1XXA is the ICD-10-CM code for a strain of the muscles, fascia, or tendons of the neck at the initial encounter. It is the muscular counterpart to the ligament sprain code S13.4XXA and the two frequently travel together on collision cases.
Searched as neck strain ICD 10, cervical muscle strain code, and pulled neck muscle diagnosis code.
When does a chiropractor use S16.1XXA?
Documents the muscular component of a neck trauma: guarding, spasm, and the palpable hypertonicity a DC finds on day one after a collision. Coding both the sprain and the strain when both are documented paints the fuller injury picture, supports the soft tissue work billed under 97140 and 97124, and reads as a more complete clinical assessment in the PI file.
Coding rules that matter
- ✓Seven characters required, with the same A, D, S encounter progression as all S codes
- ✓Distinct from the ligament sprain S13.4XXA; code both only when the exam documents both
- ✓Muscle spasm without trauma belongs on M62.830 instead; S16.1 asserts an injury mechanism
The codes around S16.1XXA
| Code | Description |
|---|---|
| S16.1XXA | Neck muscle strain, initial encounter (this code) |
| S16.1XXD | Neck muscle strain, subsequent encounter |
| S16.1XXS | Neck muscle strain, sequela |
| S13.4XXA | Cervical ligament sprain, initial encounter |
When S16.1XXA is the wrong code
Not for chronic muscle tightness with no event, which is M62.838 or myalgia in M79.1. Not a substitute for the ligament sprain S13.4XXA; on collision cases with both findings, both are coded. Sprain is ligament, strain is muscle, and payers notice when the words are swapped.
How does S16.1XXA work on Medicare chiropractic claims?
A secondary diagnosis behind the regional subluxation code when Medicare is ever the payer. In the usual PI context it supports therapy service lines on the same claim as the CMT codes.
Where claims go wrong
Using it for non traumatic muscle pain; letting it point at nothing, with no therapy line tied to the muscular finding; seventh character drift.
How Cervica helps with S16.1XXA
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 S16.1XXA mean?
S16.1XXA is the ICD-10-CM code for a strain of the muscles, fascia, or tendons of the neck at the initial encounter. It is the muscular counterpart to the ligament sprain code S13.4XXA and the two frequently travel together on collision cases.
When does a chiropractor use S16.1XXA?
Documents the muscular component of a neck trauma: guarding, spasm, and the palpable hypertonicity a DC finds on day one after a collision. Coding both the sprain and the strain when both are documented paints the fuller injury picture, supports the soft tissue work billed under 97140 and 97124, and reads as a more complete clinical assessment in the PI file.
How does S16.1XXA work on Medicare chiropractic claims?
A secondary diagnosis behind the regional subluxation code when Medicare is ever the payer. In the usual PI context it supports therapy service lines on the same claim as the CMT codes.
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.