Intramuscular Injection (IMI)

Last updated 20.09.12



-  Administration of medications deep into muscle tissue


IMI Skin



-  Rapid absorption of large doses of medication

-  Typically longer duration of effect than IV & slower onset of action



-  Vaccination

-  Adrenaline for anaphylaxis

-  Patient without IV access requiring analgesia, antiemetics, etc.

-  Uncoperative patients: antipsychotics, sedatives

-  Preferred route for depo injections: antipsychotics, contraception (Depo-Provera)

-  Antibiotics



-  Non-sterile gloves

-  Alcohol preb/mediswab

-  18-24G needle 2.5cm

-  3ml Syringe

-  Medication

-  Bandaid/gauze/cotton wool

-  Sharps container



-  Consent

-  Parental for childhood immunisations

-  Not required for acute management of psychotic patients

-  Select injection site

-  Postion patient appropriately

-  Clean hands, gloves

-  Clean site with swab & allow to air dry

-  Stretch skin over injection site with non-dominant hand

-  Insert needle at 70-90o angle

-  Aspirate plunger to ensure no blood

-  If blood withdraw needle & discard

-  Repeat process

-  Slowly depress plunger until full dose administered

-  Withdraw needle & release skin

-  Bandaid/gauze/cotton wool to wound

-  Document medication



-  Fibrosis & contracture of muscle

-  Muscle contraction

-  Nerve injury or neuropathy

-  Abscess &/or haematoma

-  Tisseu necrosis or gangrene

-  Local irritation



-  Based on purpose of injection, body size, age, muscle condition & indication

-  Ventrogluteal

-  Free of nerves, greatest thickness, least pain

-   Must avoid sciatic nerve

-  Most common site for Abx & anti-emetics

-  Can inject up to 2.5ml

-  Consistant depth of subcutaneous adipose

-  Location

-   Between ASIS & greater trochanter of femur

-   Place palm of hand on greater trochanter

-   Place index finger on ASIS

-   Extend middle finger towards iliac crest

-   V formed by index & middle fingers indicates site of injection

-   Gluteus medius & gluteus minimus




-  Deltoid

-  Most accessible site

-  Can inject up to 1ml

-  Performed with bent elbow

-  Avoid in children

-  Location

-   Midpoint between acromial process of scapula & midpoint of lateral humerus

-   Approximately 2.5-5cm inferior to acromium process




-  Dorsogluteal

-  Lowest absorption rate

-  Beware of muscular atrophy

-  Overall most common site

-  Patient prone

-  Location

-   5-8cm inferior to liac crest

-   Upper outer quadrant of buttock

-   Superiolateral to line joining PSIS & greater trochanter of femur




-  Vastus Lateralis

-  Can inject up to 5ml

-  Location

-   Anterolateral aspect of thigh

-   Middle third of muscle


Vastus Lateralis



-  Bleeding diathesis including anticoagulation

-  Neutropaenia

-  Inflamed, oedematous, irritated injection site

-  May be less well absorbed with peripheral vascular disease






King Edward Memorial Hospital: Clinical Guidelines: Intramuscular Injections, June 2010

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