Intramuscular Injection

Continuing Education Activity

This activity outlines and highlights the role of the interprofessional team in improving care for patients who undergo the intramuscular injection. This activity also summarizes the anatomic landmarks, safety precautionary checklists, the recommended procedural steps, and the complications to be aware of following the procedure.


  • Identify the anatomical landmarks for intramuscular injection.
  • Describe the of intramuscular injections.
  • Summarize the potential complications of intramuscular injection.
  • Review interprofessional team strategies for improving care coordination and communication to advance intramuscular injection and improve outcomes.


Intramuscular injection is the method of installing medications into the depth of the bulk of specifically selected muscles.[1] The basis of this process is that the bulky muscles have good vascularity, and therefore the injected drug quickly reaches the systemic circulation and thereafter into the specific region of action, bypassing the first-pass metabolism.[2] It is one of the most common medical procedures to be performed on an annual basis. However, there is still a lack of uniform guidelines and an algorithm in giving IM among health professionals across the world.[2] 

Drugs may be given intramuscularly both for prophylactic as well as curative purposes, and the most common medications include[2]:

  • Antibiotics- penicillin G benzathine penicillin, streptomycin
  • Biologicals- immunoglobins, vaccines, and toxoids
  • Hormonal agents- testosterone, medroxyprogesterone

Any drugs that are nonirritant and soluble may be given IM during an emergency scenario.

Anatomy and Physiology

Anatomical Landmarks

There are specific landmarks to be taken into consideration while giving IM injections so as to avoid any neurovascular complications. The specific landmarks for the most commonly used sites are discussed below

Dorsogluteal Region[3]

  • 5 to 7.5 cm below the iliac crest.
  • Upper outer quadrant of the upper outer quadrant within the buttocks

Ventrogluteal Region[3]

  • The heel of the opposing hand is placed in the greater trochanter, the index finger in the anterior superior iliac spine and the middle finger below the iliac crest. The drug is injected in the triangle formed by the index, middle finger, and the iliac crest


  • 2.5 to 5 cm below the acromion process

Vastus Lateralis

  • The middle third of the line joining the greater trochanter of the femur and the lateral femoral condyle of the knee[4]


IM is commonly indicated for patients who are [2]:

  • Noncompliant
  • Uncooperative
  • Reluctant 
  • Unable to receive drugs through other commonly utilized routes


  • Active infection, cellulitis or dermatitis at the site of administration
  • Known allergy or hypersensitivity to the drug
  • Acute myocardial infarction- the release of muscle enzymes may provide a confounding bias in making the diagnosis
  • Thrombocytopenia
  • Coagulation defects
  • Hypovolemic shock- the absorption of the drug may be hampered owing to compromised vascularity to the muscle
  • Myopathies
  • Associated muscular atrophy- leads to delayed drug absorption as well as adds up the risk of neurovascular complications


  1. 20-25 gauge syringe with a needle length of 16-38 mm
  2. Filter needle 
  3. Alcohol-based antiseptic solution
  4. The correct drug in an appropriate dose
  5. Dry cotton swab
  6. Self-adhesive bandage
  7. Needle disposal unit


  • A trained nurse or a paramedics
  • The treating physician


Prerequisite- ensure the 5 'Rs'

  • Right patient
  • Right drug
  • Right dose
  • Right site
  • Right timing

Ask for any adverse reactions in previous such procedures.

Counseling regarding the procedure and preparing the patient- to calm them down and also to minimize the pain associated with the procedure


Site selection[2]

  1. Infants- vastus lateralis
  2. Children- vastus lateralis and deltoid 
  3. Adults- ventrogluteal and deltoid

Drug volume[5]

2 ml or less- deltoid injection

2 to 5 ml       - Ventrogluteal injection

Needle length[2]

Vastus lateralis -16 to 25 mm

Deltoid-16 to 32 mm (children), 25 to 38 mm(adults)

Ventrogluteal-38 mm


The sequential method of IM injection can be summarised as follows[2][1][5]

  1. Thorough cleaning of the hands
  2. Application of sterile gloves
  3. Thorough cleansing surrounding the site of injection with an alcohol-based antiseptic solution
  4. Perpendicular insertion of a needle of appropriate sized length[6]
  5. Prepare the drug and then aspirate it from the filter needle
  6. Insure intramuscular positioning of the needle via confirming restricted side to side movement of the needle as opposed to when the needle is in the subcutaneous plane
  7. Aspirate to rule out any egress of blood especially in cases of dorsogluteal injection due to inadvertent vascular puncturing of the gluteal artery during the procedure[7][8]
  8. Slow injection of the drug at 10 sec/ml
  9. Slow withdrawal the needle and then apply gentle pressure over the injected site with a dry cotton swab
  10. Proper disposal of all the equipment used during the procedure[9]
  11. Assessment of  the injected region for probable early and late complications


Common complications  associated with the intramuscular injection can be summarized as [5]:

  1. Muscle fibrosis and contracture
  2. Abscess at the injection site
  3. Gangrene
  4. Nerve injury -the sciatic nerve in gluteal injection, the femoral nerve in vastus lateralis injection
  5. Vascular injury- the superior gluteal nerve in dorsogluteal injection, the femoral nerve in vastus lateralis injection, radial nerve in deltoid injection
  6. Skin slough
  7. Periostitis
  8. Transmission of HIV, hepatitis virus
  9. Persistent pain at the site of injection

Clinical Significance


  • Rapid and uniform absorption of the drug especially those of the aqueous solutions
  • Rapid onset of the action compared to that of the oral and the subcutaneous routes
  • IM injection bypasses the first-pass metabolism 
  • It also avoids the gastric factors governing the drug absorption
  • Has efficacy and potency comparable to that of the intravenous drug delivery system.
  • Highly efficacious in emergency scenarios such as acute psychosis and status epilepticus
  • Depot injections allow slow, sustained and prolonged  action
  • A large volume of the drug can be administered compared to that of the subcutaneous route


  • Expert and a trained person is required for administrating the drug by IM route
  • The absorption of the drug is determined by the bulk of the muscle and its vascularity
  • The onset and duration of the action of the drug is not adjustable 
  • In case of inadvertent scenarios such as anaphylaxis or neurovascular injuries, intravenous (IV) assess needs to be secured
  • IM injection at the appropriate landmarks may be difficult in a child as well as in  patients requiring physical restrain
  • Inadvertent injection in the subcutaneous plane of the fascia can lead to delayed action of the drug
  • Painful procedure
  • Suspensions, as well as oily drugs, cannot be administered
  • Can lead to anxiety to the patient especially in children
  • Self-administration of the drug can be difficult
  • The precipitation of the drug following faster absorption of the solvent may lead to delayed and prolonged action of the drug
  • Unintended prolonged sequelae following delayed drug release from the muscular compartment
  • Need for temporary restraint of the patients especially in cases with children

Enhancing Healthcare Team Outcomes

The formulation of set guidelines and procedural algorithms for IM injections is of paramount importance in assuring effective pharmacokinetics and the pharmacodynamics of the drugs.[7]

The thorough knowledge pertaining to the specific anatomical landmarks helps in minimize the neurovascular complications that harbinger the IM procedures.

The strict adherence to aseptic precautionary measures and timely disposal of the used equipment helps to minimize the transmission of blood-borne infections.

The ventrogluteal site is considered the safest for IM injection owing to the thin plane of subcutaneous tissues as well as the relatively thick bulk of the underlying muscle.[10]

Nursing, Allied Health, and Interprofessional Team Interventions

The pain associated with the intramuscular injection can be reduced by the application of the skin traction and deep pressure over the muscle before the injection.[11]

The simple step of asking the patient to cough vigorously just prior to injection also helps in reducing the pain associated with the procedure. The transmission of the cough impulse is faster than that of the pain impulse traveling through the slow conducting nerve fibers; thereby, it helps in minimizing the impact of the pain threshold perceived by the brain.

(Click Image to Enlarge)
IM Injection, Buttocks, Intramuscular
IM Injection, Buttocks, Intramuscular
Contributed by Steve Bhimji, MS, MD, PhD
Article Details

Article Author

Javier Polania Gutierrez

Article Editor:

Sunil Munakomi


4/7/2021 7:51:32 AM



Shaw H, Intramuscular injection. Nursing standard (Royal College of Nursing (Great Britain) : 1987). 2015 Oct 7;     [PubMed PMID: 26443178]


Nicoll LH,Hesby A, Intramuscular injection: an integrative research review and guideline for evidence-based practice. Applied nursing research : ANR. 2002 Aug;     [PubMed PMID: 12173166]


Soliman E,Ranjan S,Xu T,Gee C,Harker A,Barrera A,Geddes J, A narrative review of the success of intramuscular gluteal injections and its impact in psychiatry. Bio-design and manufacturing. 2018;     [PubMed PMID: 30546922]


Nakajima Y,Fujii T,Mukai K,Ishida A,Kato M,Takahashi M,Tsuda M,Hashiba N,Mori N,Yamanaka A,Ozaki N,Nakatani T, Anatomically safe sites for intramuscular injections: a cross-sectional study on young adults and cadavers with a focus on the thigh. Human vaccines     [PubMed PMID: 31403356]


Rodger MA,King L, Drawing up and administering intramuscular injections: a review of the literature. Journal of advanced nursing. 2000 Mar;     [PubMed PMID: 10718876]


Warren BL, Intramuscular injection angle: evidence for practice? Nursing praxis in New Zealand inc. 2002 Jul;     [PubMed PMID: 12238797]


Sisson H, Aspirating during the intramuscular injection procedure: a systematic literature review. Journal of clinical nursing. 2015 Sep;     [PubMed PMID: 25871949]


Thomas CM,Mraz M,Rajcan L, Blood Aspiration During IM Injection. Clinical nursing research. 2016 Oct;     [PubMed PMID: 25784149]


Al Awaidy S,Bawikar S,Duclos P, Safe injection practices in a primary health care setting in Oman. Eastern Mediterranean health journal = La revue de sante de la Mediterranee orientale = al-Majallah al-sihhiyah li-sharq al-mutawassit. 2006;     [PubMed PMID: 17361692]


Donaldson C,Green J, Using the ventrogluteal site for intramuscular injections. Nursing times. 2005 Apr 19-25;     [PubMed PMID: 15871375]


Salari M,Estaji Z,Akrami R,Rad M, Comparison of skin traction, pressure, and rapid muscle release with conventional method on intramuscular injection pain: A randomized clinical trial. Journal of education and health promotion. 2018;     [PubMed PMID: 30693308]