1.
Injection site: Anterolateral thigh
Muscle: Vastus lateralis
Origin: Intertrochanteric line and gluteal tuberosity
Insertion: Tibial tuberosity (via patellar ligament) and Patella
Action: Extends the leg
How to locate: Divide the thighs into three categories. That being the greater trochanter being in the upper anatomical landmarks and patella being on the lower anatomical landmarks. The middle part is where you’ll be able to locate the Vastus lateralis.
2.
Injection site: Upper Arm
Muscle: Deltoid
Origin: Lateral 1/3 of Clavicle (clavicular part), Acromion (acromial part), Spine of Scapula (spinal part)
Insertion: Deltoid tuberosity of humerus
Action: The deltoid muscle is the principal abductor of the arm at the glenohumeral joint. Clavicular (anterior) fibers of deltoid help with flexion of the arm. Furthermore scapular spinal (posterior) fibers, together with the latissimus dorsi assist in the extension of the arm.
How to locate: Expose the whole arm (shoulder to elbow) and locate the upper anatomical landmark which is the acromion (shoulder tip). Below that you will locate the muscle insertion of the deltoid (deltoid tuberosity). Once found, imagine an inverted triangle below the acromion and halfway between the shoulder tip and deltoid is the point of insertion.
Source: Muscles of facial expression. (2020). Kenhub. https://www.kenhub.com/en/library/anatomy/orbicularis-oris-muscle