1. The sites of injection: Anterolateral aspect of the thigh
Targeted muscle for injection: Vastus Lateralis
Origin: Upper inter-trochanteric line, base of greater trochanter, lateral linea aspera, lateral supracondylar ridge and lateral intermuscular septum
Insertion: Lateral quadriceps tendon which attached onto the tibial tubercle
Action: Extension of the knee
How do you locate this area?
Divide the thigh into thirds to determine the injection site. Make sure to stay away from blood vessels and bones by injecting into the middle third of the anterolateral side of the thigh.
2. The preferred site for IM injection in the 65-year-old grandfather case is the Deltoid Muscle in the upper arm.
Origin:
- Anterior Fibres/Head: Lateral third, Anterior Surface of the Clavicle (close to the lateral fibres of pectoralis major).
- Mid/Lateral Head: Acromion Process scapula, Superior Surface.
- Posterior Head: Spine of the Scapula, Posterior Border.
Insertion:
- Fibres from all heads converge to insert into the deltoid tuberosity on the humerus.
- The deltoid fascia is continuous with the brachial fascia and connects to the medial and lateral intermuscular septa
Action: Abduct the arm at the shoulder joint. Also plays a role in flexing, extending, and medially rotating the arm.
How do you locate this area?
Deltoid: Give in the central and thickest portion of the deltoid muscle – above the level of the armpit and approximately 2–3 fingerbreadths (~2") below the acromion process (see diagram 1). To avoid causing an injury, do not inject too high (near the acromion process) or too low.
Reference: https://www.physio-pedia.com/Vastus_Lateralis
https://www.physio-pedia.com/Deltoid?utm_source=physiopedia&utm_medium=search&utm_campaign=ongoing_internal
https://www.immunize.org/catg.d/p2020a.pdf