#1 2-month old female infant
Injection site: Thigh
Muscle: Vastus lateralis muscle
Origin: Greater trochanter & linea aspera of femur
Insertion: Patella through the quadriceps tendon and tibial tuberosity through the patellar ligament
Action: All 4 heads extend leg at knee joint, rectus femoris muscle acting alone also flexes thigh at hip joint
Location: In order to identify the vastus lateralis, the patient should be lying down or being supported by a parent. Palpate the muscle below the greater trochanter and above the lateral femoral condyle (knee joint), divide it into thirds, and inject the middle third of the muscle in the outer anterolateral aspect, lateral to the midpoint of the thigh.
#2 65-year-old grandfather
Injection site: Upper Arm
Muscle: Deltoid muscle of the shoulder
Origin: Acromial extremity of clavicle, acromion of scapula, and spine of scapula
Insertion: Deltoid tuberosity of humerus
Action: Lateral fibers abduct arm at shoulder joint; anterior fibers flex and medially rotate arm at shoulder joint; posterior fibers extend and laterally rotate arm at shoulder joint.
Location: When the upper arm is exposed, locate the acromion process by palpating the bony protrusion to find the landmark for the deltoid muscle. A few millimeters (2.5–5 cm) below the acromion process, in the middle of the deltoid muscle, is where the injection will take place. Place three fingers below the acromion process and across the deltoid muscle to identify this location. Three finger widths below, in the center of the muscle, is often where the injection will take place.
REFERENCES:
The Royal Children's Hospital Melbourne. (n.d.) Intramuscular Injections. https://www.rch.org.au/rchcpg/hospital_clinical_guideline_index/Intramuscular_Injections/
Tortora, G. J., & Derrickson, B. (2017). Principles of anatomy & physiology. Fifteenth edition; Wiley Loose-Leaf Print Companion. Hoboken, New Jersey, John Wiley & Sons, Inc.
Wisconsin Technical College System. (n.d.). Administering Intramuscular Medications. Nursing Skills - 2e. https://wtcs.pressbooks.pub/nursingskills/chapter/18-6-administering-intramuscular-medications/