- Cafasso (2023) defined intramuscular injection, as a process where medication is injected into the muscles and quickly absorbed by the blood vessels. In line with this, the preferred site of injection for infants, such as 2-month-old, is on the anterolateral thigh particularly in the vastus lateralis muscle, because it is thicker and more developed compared to their deltoid muscle, which is another site for intramuscular injection. It is also far from any blood vessels or nerves, making it safer as an injection site. The origin of this muscle is on the greater trochanter and linea aspera of the femur, while its insertion is in the patella through the quadriceps tendon and tibial tuberosity through the patellar ligament. On the other hand, its action is all four head legs at the knee joint. Moreover, the injection site of this muscle is the middle third of the lateral thigh between the trochanter major and the knee.
- For a 65- year-old grandfather or adults in general, the preferred injection site would be the deltoid muscle as this is far from any large vessels and within reach of the needle. The origin of this muscle is in the acromial extremity of the clavicle, acromion of the scapula, and spine of the scapula. The insertion, on the other hand, is at the deltoid tuberosity of the humerus. While the action of the lateral fibers at the shoulder joint is abduction; the anterior fibers at the shoulder joint flex and rotate the arm medially; and the posterior fibers at the shoulder joint extend and rotate the arm laterally. To locate this muscle, the vaccinator must first locate the acromion process, which is found on the anterior projection from the lateral end of the scapula’s spine, and then palpate its bony prominence. Then, put 2-3 fingers width down from the acromion process and imagine a triangle, where the base is the acromion process and the apex points toward the elbow, the injection site would be in the triangle’s circle.
References
Anderson, R., & McKenzie, W. (n.d.). 7.4 Intramuscular Injections – Clinical Procedures for Safer Patient Care. BC Open Textbooks. Retrieved September 17, 2024, from https://opentextbc.ca/clinicalskills/chapter/6-8-iv-push-medications-and-saline-lock-flush/
Cafasso, J., & Chastain, M. (2023, April 21). Intramuscular Injection: Definition and Patient Education. Healthline. Retrieved September 17, 2024, from https://www.healthline.com/health/intramuscular-injection
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. Hum Vaccin Immunother. 2020;16(1):189-196. doi: 10.1080/21645515.2019.1646576. Epub 2019 Aug 23. PMID: 31403356; PMCID: PMC7012163.
Tortora, G. J., Derrickson, B., Burkett, B., Peoples, G., Dye, D., Cooke, J., Diversi, T., McKean, M., Samalia, L., & Mellifont, R. (2022). Principles of anatomy and physiology (3rd ed.). John Wiley & Sons Australia, Ltd.