1. Vastus lateratis muscle
origin: greater trochanter and linea aspera of femur
insertion: patella via quadriceps tendon and then tibial tuberosity via patellar ligament
action: extend leg at knee joint
how to locate: locate the junction of the upper and middle thirds of the vastus lateralis thigh muscle
2. Deltoid muscle
origin: acromial extremity of clavicle (anterior fibers), acromion of scapula (lateral fibers), and spine of scapula (posterior fibers)
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
how to locate: feel for the acromion process (prominent bony part at the top of the arm) with your dominant hand. then use two fingers to landmark under the acromion process to make sure that you are not going into the joint. after that, draw an imaginary line across the axillary fold then place your hand on the arm (make sure it is not under the axillary fold) and inject at the center of the “triangle” created by the landmarks (two fingers below the acromion process and hand placed not under the axillary fold)
Safer Care Victoria. (2017, June). Intramuscular injections for neonates. https://www.safercare.vic.gov.au/clinical-guidance/neonatal/intramuscular-injections-for-neonates
HSE National Immunisation Office, Ireland. (2021, April 9). Landmarking and administration of deltoid injection technique intramuscular [Video]. YouTube. https://www.youtube.com/watch?v=Y7cZZL2MzYo
Tortora, G. J., & Derrickson, B. (2017). Tortora’s Principles of Anatomy and Physiology. In John Wiley & Sons, Inc. eBooks. https://ci.nii.ac.jp/ncid/BB23861293