The Risks of An Incorrect Intramuscular Injection

Incorrect intramuscular injections can cause serious and sometimes permanent injuries—including nerve damage, muscle atrophy, chronic pain, and loss of mobility. While intramuscular (IM) injections are widely used and generally safe when performed properly, even a small error in technique, needle placement, or injection site selection can lead to significant medical complications.

When administered correctly, intramuscular injections deliver medication deep into muscle tissue, allowing for fast and effective absorption into the bloodstream. However, improper administration can damage nerves, injure muscle tissue, introduce infection, or result in the medication being delivered to the wrong anatomical structure. In severe cases, patients may experience long-term disability, reduced range of motion, or ongoing neurological symptoms.

Understanding the risks associated with incorrect intramuscular injections is critical for both healthcare providers and patients. Injuries such as sciatic nerve damage, shoulder injury related to vaccine administration (SIRVA), and localized tissue necrosis are often preventable—yet they continue to occur due to poor technique, inadequate training, or improper site selection.

Intramuscular Injections Explained

An intramuscular injection (IM injection) is a medical technique used to deliver medication directly into muscle tissue, where it can be absorbed quickly into the bloodstream. This method is commonly used for vaccines, antibiotics, hormone therapies, and other medications that require rapid or sustained absorption and are not suitable for oral delivery.

IM injections involve passing a needle through the skin and subcutaneous fat layer to reach the underlying muscle. Proper technique—including correct landmarking, needle length selection, and injection angle—is essential to avoid complications such as nerve injury, muscle damage, or improper medication delivery.

By choosing the appropriate injection site and following established clinical guidelines, healthcare providers can reduce the risk of injury and ensure safe, effective medication administration. When these standards are not followed, however, the consequences can be serious—and in some cases, life-altering.

Dangers of Incorrect Injections

When an intramuscular injection is administered incorrectly, it can lead to serious complications affecting muscle tissue, nerves, and blood vessels. Some of the most common risks include:

• Nerve damage – If the needle penetrates a nerve or blood vessel, it can cause severe pain, tingling, numbness, or even paralysis in extreme cases.
• Muscle damage – An incorrect injection technique may lead to muscle atrophy, scar tissue formation, or long-term weakness.
• Blood vessel injury – Injecting too close to major blood vessels may result in excessive bleeding, hematomas, or localized infections.
• Injection site reactions – Symptoms such as redness, swelling, or increased pain at the injection site may indicate improper technique or an adverse reaction.
• Medication leakage – If the needle does not penetrate deep enough into muscle tissue, the medication administered may leak into fatty tissue, reducing its effectiveness.

Take Control of Your Injury Today

How to Choose the Right Injection Site

Selecting the correct intramuscular injection site is important in preventing serious complications such as nerve damage, tissue damage, and injection site infections. The appropriate site depends on factors like age, muscle mass, and the type of medication administered. The most commonly used intramuscular injection sites include:

• Deltoid muscle (upper arm) – Frequently used for vaccine administration and small volume injections. However, improper placement can increase the risk of hitting a nerve or blood vessel.
• Vastus lateralis muscle (thigh) – Often the preferred site for infants and young children due to its large muscle mass and fewer major blood vessels.
• Gluteus medius muscle (buttock muscle) – Typically used for larger medication volumes, but incorrect injection technique can lead to sciatic nerve injury if the needle is placed incorrectly.

How to Avoid Injection Mistakes

Avoiding incorrect injections requires a combination of proper training, site selection, and adherence to medical guidelines. Healthcare providers play an important role in ensuring safe medication administration by implementing the following best practices:

• Proper training – Medical professionals should undergo regular training on injection techniques to stay updated on best practices and avoid incorrect injection technique errors.
• Accurate site selection – Choosing the appropriate intramuscular injection site based on muscle mass, age, and medication type helps prevent complications like sciatic nerve injury or blood vessel penetration.
• Using the correct needle length – The needle length should be selected based on the patient’s muscle tissue and fatty tissue to ensure the medication administered is properly absorbed and does not leak into surrounding subcutaneous tissue.
• Rotating injection sites – Repeated injections in the same site can cause scar tissue buildup, leading to muscle damage and reduced medication effectiveness.
• Following strict hygiene protocols – Making sure the injection site is clean and using a sterile needle helps prevent localized infections and adverse reactions.

Warning Signs of a Bad Injection

When an intramuscular injection is administered incorrectly, it can cause immediate or delayed complications. Some of the most common signs that an injection may have been misplaced or performed incorrectly include:

• Severe pain at the injection site – While mild discomfort is normal, intense or prolonged pain may indicate nerve damage or improper placement.
• Swelling, redness, or warmth – These symptoms could suggest localized infections, tissue damage, or an adverse reaction.
• Bruising or excessive bleeding – May occur if the needle penetrates a blood vessel instead of muscle tissue.
• Numbness or tingling – A sign that the needle may have hit a nerve or blood vessel, potentially leading to sciatic nerve injury or long-term nerve damage.
• Limited range of motion or muscle weakness – This could indicate muscle damage, scar tissue formation, or improper absorption of the medication administered.
• Medication leakage – If the needle does not penetrate deep enough, the medication may leak into fatty tissue instead of being absorbed into muscle tissue, reducing its effectiveness.

Have an Injury?

Sciatic Nerve Injuries from Injections

The sciatic nerve is the largest nerve in the body, running from the lower back down through the legs. When an intramuscular injection is administered incorrectly in the buttock muscle, it can result in sciatic nerve injury, leading to severe and sometimes permanent complications.

Signs of sciatic nerve damage from an injection include:

• Sharp, radiating pain from the injection site down the leg
• Numbness or tingling in the lower extremity
• Muscle weakness or difficulty walking
• Loss of reflexes in the affected leg
• Chronic nerve pain that may worsen over time

Incorrect placement of an intramuscular injection in the gluteus medius muscle increases the risk of sciatic nerve injury. To minimize this risk, healthcare providers must inject into the upper outer quadrant of the buttock muscle, avoiding the nerve’s pathway.

If sciatic nerve damage occurs, medical attention is necessary to assess the severity of the injury and determine appropriate treatment options. In some cases, physical therapy, pain management, or even surgical intervention may be required to address long-term complications.

What to Do After a Wrong Injection

If you suspect that an intramuscular injection was administered incorrectly, taking prompt action can help minimize complications and prevent long-term damage. Here’s what to do:

Monitor symptoms closely – Pay attention to any signs of severe pain, swelling, numbness, or weakness at the injection site or in the surrounding area.

Seek medical attention – If symptoms persist or worsen, a healthcare professional can assess potential nerve damage, tissue damage, or blood vessel injury.

Report the incident – Inform the healthcare provider who administered the injection to make sure it is documented. This can help prevent future occurrences and may be important for legal or medical follow-ups.

Follow-up with specialists – If sciatic nerve injury or muscle damage is suspected, a neurologist or physical therapist may be needed for further evaluation and treatment.

Avoid repeated injections in the same location – Repeated injections in an area that has already been affected can worsen scar tissue formation and delay healing.

Lasting Effects of Injection Mistakes

When an intramuscular injection is administered incorrectly, the damage may not always be immediate. Some complications develop over time, leading to long-term pain, mobility issues, and functional impairment.

Common long-term effects include:

• Ongoing nerve pain or numbness – If a nerve is damaged, symptoms can persist for months or even become permanent.
• Limited mobility or muscle weakness – Injury to muscle tissue may make it difficult to perform daily activities, especially if the affected area is weight-bearing (e.g., knee joint or upper arm).
• Chronic inflammation and scar tissue – Repeated injections in the same site can cause scar tissue buildup, reducing flexibility and making future injections more painful.
• Medication absorption issues – Improper injection techniques can affect how well medications work, potentially leading to treatment failures.

Managing long-term complications may require:

• Physical therapy to restore strength and mobility
• Pain management for chronic discomfort
• Nerve function testing if symptoms persist
• Medical intervention for severe cases, including surgical repair of damaged tissue

Get Help Today

SIRVA: Shoulder Injuries from Injections

Shoulder Injury Related to Vaccine Administration (SIRVA) occurs when a vaccine injection is given too high or too deep in the deltoid muscle (upper arm), causing nerve damage, inflammation, or joint injury. Unlike typical injection site soreness, SIRVA can lead to long-term pain and restricted mobility.

Common symptoms of SIRVA include:

• Severe, persistent shoulder pain that does not improve with time
• Limited range of motion due to inflammation or muscle damage
• Weakness or numbness in the upper arm, suggesting nerve or blood vessel involvement
• Chronic inflammation affecting the shoulder joint

Because SIRVA results from incorrect injection technique, it is entirely preventable. Healthcare providers must guarantee proper injection site selection and needle placement to avoid causing tissue damage or penetrating too deep into surrounding muscle tissue.

Legal Options for Injection Injuries

An incorrectly administered intramuscular injection can lead to severe pain, nerve damage, and long-term health complications. Whether it’s sciatic nerve injury, SIRVA, chronic pain, or reduced mobility, these injuries can significantly impact daily life. In some cases, they may even require medical treatment, physical therapy, or ongoing pain management.

If you have suffered serious complications due to a misplaced intramuscular injection, you may have legal options. My Vaccine Lawyer specializes in cases involving vaccine-related injuries and medical negligence, helping victims recover compensation for pain, medical expenses, and lost quality of life.

Work With Us At No Cost