| A | B |
| iliac crest | Upper part of the pelvis |
| immune response | A series of reactions that are the body's defense mechanism against invading viruses, bacteria, and toxins |
| impaled object | An object that pierces the skin |
| implied consent | Used for unconscious or mentally incompetent patients requiring emergency intervention; based on the assumption taht the patient would give permission to treat lift-threatening conditions |
| incident management system (IMS) | A system designed to control, direct, and coordinate emergency responders and resources in case of a disater |
| indication | A sign, symptom, or condition for which a specific medication or treatment is given |
| indirect force | A transmitted force that causes injury some distance away from the point of impact |
| inferior | Below or beneath another structure |
| ingested poison | A liquid or solid toxic substance that is swallowed |
| inhaled poison | A toxic substance such as a gas, fumes, vapor, or spray that is breathed in |
| initial assessment | Conducted after scene size-up in order to find and manage any life-threatening conditions |
| injected poison | A toxic substance that enters the body through a puncture in the skin; injection may be by needle, animal bite, or insect sting |
| inspiration | Taking air into the lungs (inhalation) |
| insulin | Hormone secreted by the pancreas that regulates blood sugar levels |
| intercostal muscles | Muscles located between the ribs; involving in breathing |
| interventions | Procedures done in an effort to improve the patient's condition |
| involuntary muscle | Muscles that carry out the automatic muscular functions of the body |
| ischium | One of the bones forming the pelvis |