1. Injection Site: Vastus lateralis muscle in the anterolateral thigh
Origin: Intertrochanteric line, greater trochanter, gluteal tuberosity, linea aspera of femur
Insertion: Tibial tuberosity, patella
Action: Extends leg at knee joint
How to locate: make an imaginary box on the upper leg. Find the groin. One hand’s width below the groin becomes the upper border of the box. Find the top of the knee. One hand’s width above the top of the knee becomes the lower border of the box
2. Injection Site: Deltoid muscle
Origin: lateral 1/3 of clavicle, Acromion, spine of scapula
Insertion: Deltoid tuberosity of humerus
Action: Clavicular part: flexion and internal rotation of the arm,
Acromial part: abduction of the arm beyond the initial 15°
Spinal part: extension and external rotation of the arm.
How to locate: Find the knobbly top of the arm (acromion process). The top border of an inverted triangle is two finger widths down from the acromion process