Final answer:
The safest quadrant for a gluteal intramuscular injection is the upper lateral quadrant. This avoids the sciatic nerve and blood vessels. The injection should be directed into the gluteus medius muscle, away from the sciatic nerve.
Step-by-step explanation:
A gluteal intramuscular injection should be administered in the upper lateral quadrant to avoid damaging the sciatic nerve and major blood vessels which are located in the other regions. The gluteal region is divided into four quadrants, and the upper lateral quadrant is considered the safest area for an intramuscular injection. This area is located by first dividing the buttock with one horizontal and one vertical line to form quadrants, and then using the upper outer quadrant which is generally away from the sciatic nerve and blood vessels.
The gluteal muscles consist of the gluteus maximus, gluteus medius, and gluteus minimus. When administering an injection in the gluteal region, the needle should be injected into the gluteus medius muscle which is situated away from the sciatic nerve. In contrast, the vastus lateralis muscle, located on the lateral aspect of the thigh, is another safe site for intramuscular injections, specifically in infants and small children. Similar precautions should be applied when considering the vastus medialis muscle on the medial aspect of the thigh.