1. 2-month old well female infant
- Sites of injection: Anterolateral thigh
- Targeted muscle: Vastus lateralis
- Origin: Greater trochanter and lateral lip of linea aspera of the femur
- Insertion: Patella via the quadriceps femoris tendon
- Action: Extends leg at knee joint
- Steps in locating: Feel for the muscle between the greater trochanter and the lateral femoral knee joint. Divide the muscle into three equal sections and insert the needle on the middle third, specifically in the outer anterolateral area, lateral to the center of the thigh.
2. 65-year-old grandfather
- Sites of injection: Upper arm
- Targeted muscle: Deltoid
- Origin: Lateral one third of clavicle, acromion, and spine of scapula
- Insertion: Deltoid tuberosity of humerus
- Action: Abducts, flexes, extends, and medially and laterally rotates arm at shoulder joint
- Steps in locating: Feel for the bone at the top of the upper arm. Two finger-widths below it is a triangular-shaped muscle. The needle should be inserted into the center of the triangle.