IM
Abbreviation with 7 meanings
| Stands for | Intramuscular |
|---|---|
| Meanings | 7 |
| Categories | Medical, Geography & Places, Units & Measurements, Sports |
| Also written | Im, im |
IM has seven meanings. The most common are Intramuscular (medication route) and Internal medicine (medical specialty); it can also stand for Intramedullary (nail or rod), Isle of Man, Imaginary part, Individual medley and Image (of a function or linear map).
Meanings of IM at a glance
| # | IM stands for | Context |
|---|---|---|
| 1 | Intramuscular | Medical › Medication Route |
| 2 | Internal medicine | Medical › Medical Specialty |
| 3 | Intramedullary (nail or rod) | Medical › Surgical |
| 4 | Isle of Man | Geography & Places › Country Code |
| 5 | Imaginary part | Units & Measurements › Math |
| 6 | Individual medley | Sports › Other Sports |
| 7 | Image (of a function or linear map) | Units & Measurements › Math |
1. Intramuscular
Medical · Medication Route Abbreviations
Injection into a muscle, commonly the deltoid, ventrogluteal or vastus lateralis site. Muscle tissue is well supplied with blood, so absorption is faster than subcutaneous but slower than IV; vaccines, long-acting antipsychotics and some antibiotics are given IM.
Example: Ceftriaxone 250 mg IM once; Tdap 0.5 mL IM in the left deltoid.
Pronounced "I-M". ISMP warns that the abbreviation "IN" (intranasal) has been misread as IM, and vice versa. IM injections are avoided in patients with very low platelets or on full anticoagulation because of bleeding risk. Infants receive IM vaccines in the anterolateral thigh rather than the deltoid.
2. Internal medicine
Medical · Medical Specialty Abbreviations
Specialty focused on the prevention, diagnosis and nonsurgical treatment of diseases in adults, from outpatient primary care to complex hospital medicine. US internal medicine residency lasts three years and is the gateway to subspecialties such as cardiology, gastroenterology, nephrology and oncology.
Example: IM resident on night float admitted three patients from the ED.
Internists are certified by the American Board of Internal Medicine (ABIM); the word "internist" is often confused with "intern", a first-year resident. Many internists work as hospitalists, caring only for hospitalized patients. On medication orders IM means intramuscular, and in orthopedics it means intramedullary, as in an IM nail.
3. Intramedullary (nail or rod)
Medical · Surgical Abbreviations
Describes a metal rod inserted into the hollow marrow canal of a long bone, most often the femur, tibia or humerus, to stabilize a fracture. IM nailing allows early weight bearing for many shaft fractures and is the standard treatment for adult femoral shaft fractures.
Example: Right femoral shaft fracture: antegrade IM nail with proximal and distal interlocking screws.
German surgeon Gerhard Kuntscher popularized intramedullary nailing in 1939, and its use for wounded soldiers during World War II showed its value. Locking screws through the nail control rotation and length. On medication orders IM means intramuscular, and in hospital medicine internal medicine.
4. Isle of Man
Geography & Places · Country Code Abbreviations
British Crown Dependency in the Irish Sea, with Douglas as its capital, whose parliament, Tynwald, claims to be the oldest in continuous existence, traditionally dated to 979. The island hosts the TT motorcycle races each spring.
Example: Online gaming firms licensed in IM list Douglas as their registered office.
The Isle of Man is not part of the UK or the EU but is a self-governing dependency of the Crown. Its .im domain is popular for instant-messaging apps. Manx cats, which are tailless, come from the island.
5. Imaginary part (Im)
Units & Measurements · Math Abbreviations
The coefficient of i in a complex number: for z = 3 + 4i, Im(z) = 4, itself a real number. It is used in complex analysis, signal processing and physics.
Example: The roots are complex with Im(z) = ±2, so the system oscillates.
Older texts sometimes write the Fraktur letter ℑ. The imaginary unit i has Re = 0 and Im = 1. In control theory, poles with nonzero imaginary parts indicate oscillation, and their real parts determine whether it grows or decays.
6. Individual medley
Sports · Other Sports Abbreviations
Swimming event in which one swimmer covers all four strokes in equal parts, in the order butterfly, backstroke, breaststroke, freestyle. Olympic distances are 200 and 400 meters.
Example: Leon Marchand won the 400 IM in Paris in an Olympic record.
Medley relays use a different order: backstroke, breaststroke, butterfly, freestyle, because backstroke starts in the water. Michael Phelps won the 200 IM at four straight Olympics (2004-2016). In messaging IM means instant message.
7. Image (of a function or linear map) (im)
Units & Measurements · Math Abbreviations
The set of all outputs of a function or linear map, written im T or Im(T); for a matrix it equals the column space. The image of a projection onto a plane is the plane itself.
Example: Since im T is all of R³, the map T is onto.
Image and range are often used interchangeably, though some authors use range for the codomain. The dimension of im T is the rank of T, which the rank-nullity theorem links to the kernel. Capitalized Im more often means the imaginary part of a complex number, so context matters.
Related abbreviations
More medication route abbreviations
- ICV – Intracerebroventricular
- ID – Intradermal
- IJ – Injection
- IL – Intralesional
- IN – Intranasal
- INH – Inhalation
- inj – Injection
- IO – Intraosseous
See all 41 medication route abbreviations →
More medical specialty abbreviations
- GP – General practitioner
- Heme/Onc – Hematology and oncology
- HPM – Hospice and palliative medicine
- IMG – International medical graduate
- IR – Interventional radiology
- Med-Peds – Internal medicine-pediatrics
- MFM – Maternal-fetal medicine
- Nephro – Nephrology
See all 47 medical specialty abbreviations →
This entry is for general education and is not medical advice. Abbreviation use varies between institutions; always confirm in context.