Alphabetic Index FY2027

S04

Injury of cranial nerve

FY2027Chapter 19: Injury, poisoning and certain other consequences of external causes/S00–S09 Injuries to the head

Non-billable headerNot valid on its own. Use one of the more specific codes under it.

S04 is a non-billable ICD-10-CM code category for injury of cranial nerve. Report a more specific code from it instead. It is part of the FY2027 code set, effective October 1, 2026. The more specific codes under it are S04.0 Injury of optic nerve and pathways, S04.1 Injury of oculomotor nerve, S04.2 Injury of trochlear nerve, S04.3 Injury of trigeminal nerve and 6 more. Its coding notes include a Code first instruction, a Use additional code instruction, a Code also instruction and 11 Excludes2 entries.

7th characters

Every code below needs one of these.

The appropriate 7th character is to be added to each code from category S04

  • Ainitial encounter
  • Dsubsequent encounter
  • Ssequela

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

Code first

If the underlying condition listed here is present and known, sequence it first.

This code
  • any associated intracranial injury (S06.-)

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.

This code
  • any associated:
Also from chapter/block level (1 note)
Inherited from S00–S09 Injuries to the head
  • for any associated infection

Excludes2

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

Also from chapter/block level (11 notes)
Inherited from S00–S09 Injuries to the head
  • 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)
Inherited from Chapter 19 Injury, poisoning and certain other consequences of external causes
  • birth trauma (P10-P15)
  • obstetric trauma (O70-O71)

Includes

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

Also from chapter/block level (12 notes)
Inherited from S00–S09 Injuries to the head
  • 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

Inclusion terms

Conditions classified to this code.

This code
  • The selection of side should be based on the side of the body being affected

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.

More specific codes under S04 10