Alphabetic Index FY2027

S13.111A

Dislocation of C0/C1 cervical vertebrae, initial encounter

FY2027Chapter 19: Injury, poisoning and certain other consequences of external causes/S10–S19 Injuries to the neck

BillableComplete code, valid to report
Care settingsHome Health Primary · Musculoskeletal RehabilitationIRF 60% RuleHospital CCHAC

S13.111A (also written S13111A) is a billable ICD-10-CM diagnosis code for dislocation of C0/C1 cervical vertebrae, initial encounter. It is part of the FY2027 code set, effective October 1, 2026. It is one of the 75 codes in category S13 (Dislocation and sprain of joints and ligaments at neck level). The Alphabetic Index lists it under 7 entries. Its 7th character, A, means initial encounter. Its coding notes include a Use additional code instruction, a Code also instruction and 11 Excludes2 entries.

7th character

Category S13 requires a 7th character.

Assembled code S13.111A Open code

Guidelines tips

From the FY2027 Official Guidelines. ICD10Ref adds no rules of its own.

The 7th character depends on whether the patient is in active treatment, not on who sees the patient. An aftercare Z code is not used for injury aftercare.

Guidelines I.C.19.aInjuries: application of 7th charactersRead the official text

Each injury gets its own code unless a combination code exists, with the most serious injury first. Superficial injuries at the same site as a more severe injury are not coded. Injuries during medical care are coded as complications.

Guidelines I.C.19.bCoding of injuriesRead the official text

Use additional code

Add the listed code as a secondary code, if known.

Also from chapter/block level (1 note)
Inherited from Chapter 19 Injury, poisoning and certain other consequences of external causes
  • code to identify any retained foreign body, if applicable (Z18.-)

Code also

Two codes may be needed to describe the condition. This note gives no sequencing order.

Inherited from S13.1 Subluxation and dislocation of cervical vertebrae
  • any associated:
Inherited from S13 Dislocation and sprain of joints and ligaments at neck level
  • any associated open wound

Excludes2

Not included here. Both codes may be reported if the patient has both conditions.

Inherited from S13.1 Subluxation and dislocation of cervical vertebrae
Inherited from S13 Dislocation and sprain of joints and ligaments at neck level
  • strain of muscle or tendon at neck level (S16.1)
Also from chapter/block level (9 notes)
Inherited from S10–S19 Injuries to the neck
  • burns and corrosions (T20-T32)
  • effects of foreign body in esophagus (T18.1)
  • effects of foreign body in larynx (T17.3)
  • effects of foreign body in pharynx (T17.2)
  • effects of foreign body in trachea (T17.4)
  • frostbite (T33-T34)
  • insect bite or sting, venomous (T63.4)
Inherited from Chapter 19 Injury, poisoning and certain other consequences of external causes
  • birth trauma (P10-P15)
  • obstetric trauma (O70-O71)

Care settings

How CMS programs treat this code. These are CMS claim edits and list entries, not coverage or eligibility rules.

Home Health Primary

Accepted as the primary (principal) diagnosis on a home health claim. The Home Health Grouper assigns it to the Musculoskeletal Rehabilitation clinical group.

Source: CMS Home Health Grouper Software v07.2.26, effective October 1, 2026

IRF 60% Rule

On the CMS list of diagnoses used to determine presumptive compliance with the IRF 60 percent rule.

Source: CMS IRF Presumptive Compliance-3, FY 2027 IRF PPS final rule files, effective for discharges on or after October 1, 2026

Hospital CC

Counts as a complication or comorbidity (CC) when reported as a secondary diagnosis on an inpatient claim. It does not count when the principal diagnosis is one of the 238 codes in its exclusion list. Some MS-DRGs also ignore a CC or MCC that defines the DRG.

Source: CMS MS-DRG Definitions Manual v44, effective October 1, 2026, Appendix C

HAC

On the CMS list of hospital-acquired conditions (HAC 05: Falls and Trauma). When the claim reports it with a present-on-admission (POA) indicator of N (not present) or U (documentation insufficient), CMS does not pay the CC or MCC DRG for it. A POA of Y (present) or W (clinically undetermined) is paid normally.

Source: CMS MS-DRG Definitions Manual v44, effective October 1, 2026, Appendix I; CMS Hospital-Acquired Conditions (HAC) Coding page, POA indicator payment table

Includes

Further defines or gives examples of the content of the category.

Inherited from S13 Dislocation and sprain of joints and ligaments at neck level
  • avulsion of joint or ligament at neck level
  • laceration of cartilage, joint or ligament at neck level
  • sprain of cartilage, joint or ligament at neck level
  • traumatic hemarthrosis of joint or ligament at neck level
  • traumatic rupture of joint or ligament at neck level
  • traumatic subluxation of joint or ligament at neck level
  • traumatic tear of joint or ligament at neck level
Also from chapter/block level (3 notes)
Inherited from S10–S19 Injuries to the neck
  • injuries of nape
  • injuries of supraclavicular region
  • injuries of throat

Notes

Also from chapter/block level (2 notes)
Inherited from Chapter 19 Injury, poisoning and certain other consequences of external causes
  • Use secondary code(s) from Chapter 20, External causes of morbidity, to indicate cause of injury. Codes within the T section that include the external cause do not require an additional external cause code
  • The chapter uses the S-section for coding different types of injuries related to single body regions and the T-section to cover injuries to unspecified body regions as well as poisoning and certain other consequences of external causes.

Alphabetic Index terms

Terms the official Alphabetic Index lists for S13.111. This code adds the 7th character. 7 entries