1. The sites for the intramuscular injection of these vaccines are located on the anterolateral thighs of the infant. Specifically, the muscle targeted for the injection site is the vastus lateralis thigh muscle. This injection site can be located at the outer portion of the middle third of the thigh.
Origin: Greater trochanter and linea aspera of femur
Insertion: Patella via quadriceps tendon and then tibial tuberosity via patellar ligament.
Action: All four heads extend leg at knee joint; rectus femoris muscle acting alone also flexes thigh at hip joint.
2. The preferred IM injection site for influenza for patients 19 years old and older is the deltoid muscle located in the upper arm. The IM injection site in this part of the body can be located by using the central, thickest portion of the muscle, which is above the level of the armpit and approximately 2–3 fingerbreadths (~2") below the acromion process.
Origin: the lateral part of the clavicle and spine and acromion process of the scapula
Insertion: deltoid tuberosity of the humerus
Action: Arm abduction or raising arm out to the side of the body
References:
Intramuscular injections for neonates | Safer Care Victoria. (n.d.). https://www.safercare.vic.gov.au/clinical-guidance/neonatal/intramuscular-injections-for-neonates#:~:text=The%20anterolateral%20thigh%20is%20the%20preferred%20site%20for%20IM%20injection,middle%20thirds%20of%20this%20muscle.
How to Administer Intramuscular and Subcutaneous Vaccine Injections to Adults. (n.d.). https://www.immunize.org/catg.d/p2020a.pdf.
Seasonal Influenza Vaccine Dosage & Administration. (n.d.). https://www.cdc.gov/flu/about/qa/vaxadmin.htm#:~:text=For%20adults%2019%20years%20of,Deltoid%20site%20cannot%20be%20used.
Tortora, G. J., & Derrickson, B. (2017). Principles of anatomy & physiology. Fifteenth edition; Wiley Loose-Leaf Print Companion. Hoboken, New Jersey, John Wiley & Sons, Inc.