Classification of incisional hernias
| Type | Hernia gap extent in fascia level:Hernia gap in cm. | Visibility, type of finding, reponibility (restoration to normal position). |
| I | <2 cm | Hardly visible when standing or lying down; sonographic (ultrasound) or palpation (palpation) findings. |
| II | <4 cm | Visible as a protrusion when standing, flat or spontaneously reducible when lying down |
| IIb | <4 cm | Not reducible even by manual reduction |
| III | > 4 cm | Visible as a protrusion when standing, flat or spontaneously reducible when lying down |
| IV | > 4 cm | Visible in standing and supine position, reduction not spontaneous |
| IVb | > 4 cm | Not reducible even by manual reduction |
| V | Total defect of abdominal wall, monstrous prominence in standing and supine position |