S00.542A External constriction of oral cavity, initial encounter

Billable ICD-10-CM code, FY2026.

Built from S00.542 with 7th character A (initial encounter).

Applies from S00 Superficial injury of head

Excludes1 (never code together)

• diffuse cerebral contusion (S06.2-)
• focal cerebral contusion (S06.3-)
• injury of eye and orbit (S05.-)
• open wound of head (S01.-)

7th character note

• The appropriate 7th character is to be added to each code from category S00

7th character required

• A — initial encounter
• D — subsequent encounter
• S — sequela

Code annotations containing back-references to S00.542A

Back-references to S00

• Code Also: G96.00 Cerebrospinal fluid leak, unspecified ("head injury (S00-S09)")
• Code Also: G96.08 Other cranial cerebrospinal fluid leak ("head injury (S00 - S09)")
• Code Also: G96.09 Other spinal cerebrospinal fluid leak ("head injury (S00 - S09)")
• Code First: R65.1 Systemic inflammatory response syndrome (SIRS) of non-infectious origin ("injury and trauma (S00-T88)")

Diagnosis Index entries for S00.542A

• Constriction › external › alveolar process
• Constriction › external › cheek › internal
• Constriction › external › gum
• Constriction › external › head › oral cavity
• Constriction › external › mouth
• Constriction › external › oral cavity
• Constriction › external › palate
• Constriction › external › tongue
• Constriction › external › uvula

Nearby codes

• S00.541 External constriction of lip
• S00.541A External constriction of lip, initial encounter
• S00.541D External constriction of lip, subsequent encounter
• S00.541S External constriction of lip, sequela
• S00.542 External constriction of oral cavity
• S00.542A External constriction of oral cavity, initial encounter (this code)
• S00.542D External constriction of oral cavity, subsequent encounter
• S00.542S External constriction of oral cavity, sequela
• S00.55 Superficial foreign body of lip and oral cavity
• S00.551 Superficial foreign body of lip
• S00.551A Superficial foreign body of lip, initial encounter