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ICD-10-CM 2027 diagnosis code

M84.331Stress fracture, right ulna

Not billable — use a more specific codeRequires 7th character

M84.331 is a header code, so it can't be reported by itself. Choose one of the 6 more specific codes beneath it and add the required 7th character.

Code unchanged since ICD-10-CM took effect on October 1, 2015. Source: official FY2027 ICD-10-CM release from CDC/NCHS and CMS. Page updated September 29, 2026. About our data

About M84.331

M84.331 is the ICD-10-CM diagnosis code for stress fracture, right ulna. It belongs to category M84 (disorder of continuity of bone), block M80-M85 (disorders of bone density and structure) and chapter 13 (diseases of the musculoskeletal system and connective tissue). It is a header code, so it can't be reported by itself; one of its 6 subcodes must be used instead.

Within M84.33 (stress fracture, ulna and radius), M84.331 is specifically for stress fracture, right ulna. Related codes cover left ulna (M84.332), right radius (M84.333), left radius (M84.334) and unspecified ulna and radius (M84.339).

Codes in this range require a 7th character: A for initial encounter for fracture, D for subsequent encounter for fracture with routine healing, G for subsequent encounter for fracture with delayed healing, K for subsequent encounter for fracture with nonunion, P for subsequent encounter for fracture with malunion and S for sequela. Use placeholder "X" characters to fill any empty positions before the 7th character.

It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.

7th character

The appropriate 7th character is to be added to each code from subcategory M84.3:

  • Ainitial encounter for fractureM84.331A
  • Dsubsequent encounter for fracture with routine healingM84.331D
  • Gsubsequent encounter for fracture with delayed healingM84.331G
  • Ksubsequent encounter for fracture with nonunionM84.331K
  • Psubsequent encounter for fracture with malunionM84.331P
  • SsequelaM84.331S

Notes that apply from higher levels

Instructions written at a parent level also apply to M84.331.

› From M84.3 Stress fracture
Excludes1
Excludes2
  • personal history of (healed) stress (fatigue) fracture (Z87.312)
  • stress fracture of vertebra (M48.4-)
Use additional code
  • external cause code(s) to identify the cause of the stress fracture
› From M84 Disorder of continuity of bone
Excludes2
  • traumatic fracture of bone-see fracture, by site

Broader instructions also apply from Chapter 13: Diseases of the musculoskeletal system and connective tissue.

Code history

  1. 2016
  2. 2017
  3. 2018
  4. 2019
  5. 2020
  6. 2021
  7. 2022
  8. 2023
  9. 2024
  10. 2025
  11. 2026
  12. 2027
  • FY2016 (effective 10/1/2015): Added (first year of ICD-10-CM)
  • No changes since FY2016.

Common questions about M84.331

Is M84.331 billable?

No. M84.331 is a header code. Report one of its more specific subcodes instead.