S04.21XD ICD-10-CM Code: Injury of trochlear nerve, right side, subsequent encounter
S04.21XD is the authoritative medical code for Injury of trochlear nerve, right side, subsequent encounter. This classification is used in medical billing and clinical recording to specify the clinical criteria for injury of trochlear nerve, right side, subsequent encounter (ICD-10-CM S04.21XD), ensuring healthcare documentation aligns with current federal coding standards.
Billing Status: YES. This is a valid, specific, and billable ICD-10-CM reference.
Inpatient Payment Groups (MS-DRG)
MS-DRGs this diagnosis helps define, as principal or secondary, per the CMS ICD-10-CM/PCS MS-DRG Definitions Manual v43.0 (FY2026), Appendix B.
- MS-DRG 949 — AFTERCARE WITH CC/MCC (MDC 23)
- MS-DRG 950 — AFTERCARE WITHOUT CC/MCC (MDC 23)
A diagnosis appearing in a group's logic does not by itself determine the DRG assigned to a stay; the grouper uses the full claim.
Code Set: Valid FY2026 and FY2027. FY2026 took effect October 1, 2025.
Official Registry Overview & Definition
Official Tabular Instructional Notes
Sequencing, inclusion, and exclusion notes published for S04.21XD in the official ICD-10-CM tabular list.
Includes
Conditions the official ICD-10-CM tabular list includes under this code.
- injuries of ear
- injuries of eye
- injuries of face [any part]
- injuries of gum
- injuries of jaw
- injuries of oral cavity
- injuries of palate
- injuries of periocular area
- injuries of scalp
- injuries of temporomandibular joint area
- injuries of tongue
- injuries of tooth
Excludes2 — Not Included Here
Conditions not covered by this code, but which may be reported alongside it when both are present.
- burns and corrosions (T20-T32)
- effects of foreign body in ear (T16)
- effects of foreign body in larynx (T17.3)
- effects of foreign body in mouth NOS (T18.0)
- effects of foreign body in nose (T17.0-T17.1)
- effects of foreign body in pharynx (T17.2)
- effects of foreign body on external eye (T15.-)
- frostbite (T33-T34)
- insect bite or sting, venomous (T63.4)
Code First
Underlying conditions that must be sequenced before this code.
- any associated intracranial injury (S06.-)
Code Also
Additional codes that may be required to fully describe the encounter.
- any associated:
- open wound of head (S01.-)
- skull fracture (S02.-)
- for any associated infection
Frequently Asked Questions (FAQ) & Clinical Guidance
Does S04.21XD require a 7th character?
Yes. The appropriate 7th character is to be added to each code from category S04.
Can S04.21XD be reported alongside related conditions?
Per official ICD-10-CM Excludes2 instructions, S04.21XD and the following are not considered part of each other and may both be reported when both conditions are present: burns and corrosions (T20-T32); effects of foreign body in ear (T16); effects of foreign body in larynx (T17.3); effects of foreign body in mouth NOS (T18.0).
Does S04.21XD need to be sequenced after another code?
Yes. Code first: any associated intracranial injury (S06.-).
Nearest Codes in This Family
Official ICD-10-CM classifications closest to S04.21XD in its code family, with their registry titles.
- S04.20XA — Injury of trochlear nerve, unspecified side, initial encounter
- S04.20XD — Injury of trochlear nerve, unspecified side, subsequent encounter
- S04.20XS — Injury of trochlear nerve, unspecified side, sequela
- S04.21 — Injury of trochlear nerve, right side
- S04.21XA — Injury of trochlear nerve, right side, initial encounter
- S04.21XS — Injury of trochlear nerve, right side, sequela
- S04.22 — Injury of trochlear nerve, left side
- S04.22XA — Injury of trochlear nerve, left side, initial encounter
- S04.22XD — Injury of trochlear nerve, left side, subsequent encounter
- S04.22XS — Injury of trochlear nerve, left side, sequela