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Chapters ENES DE

09Diseases of the visual system
Disorders of the ocular adnexa or orbit
Disorders of orbit
9A21Orbital infection

9A21.3 category

Periostitis of orbit

Also indexed as

Periostitis of orbitorbital periostitis

Nearby in Orbital infection

9A21.0Orbital cellulitis
9A21.1Orbital subperiosteal abscess
9A21.2Orbital abscess
4B4YOther specified diseases of the immune system
4B4ZDiseases of the immune system, unspecified

Previous9A21.2 — Orbital abscess Next4B4Y — Other specified diseases of the immune system

Browse ICD-11

01Certain infectious or parasitic diseases
02Neoplasms
03Diseases of the blood or blood-forming organs
04Diseases of the immune system
05Endocrine, nutritional or metabolic diseases
06Mental, behavioural or neurodevelopmental disorders
07Sleep-wake disorders
08Diseases of the nervous system
09Diseases of the visual system
10Diseases of the ear or mastoid process
11Diseases of the circulatory system
12Diseases of the respiratory system
13Diseases of the digestive system
14Diseases of the skin
15Diseases of the musculoskeletal system or connective tissue
16Diseases of the genitourinary system
17Conditions related to sexual health
18Pregnancy, childbirth or the puerperium
19Certain conditions originating in the perinatal period
20Developmental anomalies
21Symptoms, signs or clinical findings, not elsewhere classified
22Injury, poisoning or certain other consequences of external causes
23External causes of morbidity or mortality
24Factors influencing health status or contact with health services
25Codes for special purposes
26Supplementary Chapter Traditional Medicine Conditions
VSupplementary section for functioning assessment
XExtension Codes
9A00-9A4ZDisorders of the ocular adnexa or orbit
9A60-9B3ZDisorders of the eyeball - anterior segment
9B50-9C0ZDisorders of the eyeball - posterior segment
9C20-9C2ZDisorders of the eyeball affecting both anterior and posterior segments
9C40-9C4ZDisorders of the visual pathways or centres
9C60-9C61.ZGlaucoma or glaucoma suspect
9C80-9C8ZStrabismus or ocular motility disorders
9D00-9D0ZDisorders of refraction or accommodation
9D20-9D25Postprocedural disorders of eye or ocular adnexa
6 more
9A00-9A0ZDisorders of eyelid or peri-ocular area
9A10-9A1ZDisorders of lacrimal apparatus
9A20-9A2ZDisorders of orbit
4B4YOther specified diseases of the immune system
4B4ZDiseases of the immune system, unspecified
9A20Displacement of eyeball
9A21Orbital infection
9A22Orbital inflammation
9A23Orbital cyst
9A24Bony deformity of orbit
9A25Soft tissue deformity of orbit
9A26Combined bony and soft tissue deformity of orbit
Neoplasms of orbit
Orbital trauma
2 more
9A21.0Orbital cellulitis
9A21.1Orbital subperiosteal abscess
9A21.2Orbital abscess
9A21.3Periostitis of orbit
4B4YOther specified diseases of the immune system
4B4ZDiseases of the immune system, unspecified

International Classification of Diseases, Eleventh Revision (ICD-11), World Health Organization (WHO) 2019/2021, https://icd.who.int/browse11. Licensed under Creative Commons Attribution-NoDerivatives 3.0 IGO (CC BY-ND 3.0 IGO).

Release 2026-01. View this entity in the official WHO ICD-11 browser.

This page reproduces WHO classification content for reference. It is not medical advice and must not be used to diagnose or treat. For coding decisions, consult the official release and your national coding guidelines.

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