N3 Anatomy and Physiology AY 2024-2025

2-month old well female infant

1. 1. Site of injection: Anterolateral thigh
   2. Targeted muscle: Vastus lateralis
   3. Origin: Lateral part of collarbone, the scapula’s spine and acromion 
   4. Insertion: Deltoid tuberosity of the humerus
   5. Action: Raising the arm to the side of the body (arm abduction)
   6. How to locate: Patient must be in prone position or held by parent. Palpate the muscle below the greater trochanter and above the lateral femoral condyle (knee joint). Divide the muscle into thirds and administer the injection into the middle third of the muscle, in the outer anterolateral aspect, lateral to the midpoint of the thigh.

65-year-old grandfather

1. 1. Site of injection: Upper arm
   2. Targeted muscle: Deltoid
   3. Origin: Greater trochanter, intertrochanteric line, and linea aspera of the femur 
   4. Insertion: Patella by the quadriceps tendon and tibial tuberosity by the patellar ligament
   5. Action: Extend the knee joint, moving the lower leg forward
   6. How to locate: Patient should be sitting comfortably with their arm visible from the shoulder to the top of the elbow. Palpate the acromion (outer edge of the scapula) and trace an imaginary inverted triangle below the shoulder. The injection should be given 3-5cms below the acromion, in the middle of the triangle.