Injection Technique and Route Questions

Giving injections safely means matching the route to the right angle and site, and handling the sharp without harming yourself or others. The CBT tests both the technique and the safety around it.

Route, angle and site

Three injectable routes come up most often, and each has its own depth:

• Subcutaneous, into the fatty layer just under the skin, at 45 to 90 degrees. Used for insulin and low molecular weight heparin, with sites like the abdomen and thigh rotated to protect the tissue.
• Intramuscular, into a large muscle, at 90 degrees so the needle passes through the fat to the muscle. Common sites are the deltoid and vastus lateralis, with the ventrogluteal site preferred for larger volumes.
• Intradermal, just within the skin, at a very shallow 10 to 15 degrees for tiny volumes such as skin tests.

Questions often give you a drug or a purpose and ask for the route, angle or site. Insulin subcutaneous, a large-volume medicine intramuscular, a skin test intradermal: those anchors handle most of them.

Why site and rotation matter

Depositing a drug in the wrong layer changes how it is absorbed. An intramuscular drug given too shallow ends up subcutaneous, which can affect absorption and cause irritation. And repeated injections into the same subcutaneous spot cause lumpy tissue that alters absorption, which is why rotation matters, especially for insulin.

Sharps safety

The safety point the exam always checks is what you do with the needle afterwards. You do not re-cap it. Re-capping is one of the most common causes of needlestick injury. The person who used the sharp disposes of it immediately into a sharps bin, which is not overfilled. Leaving a needle on the trolley, or handing it to someone else to deal with, puts others at risk. Next: oxygen therapy. Five injection scenarios first.