You have just received your flu vaccine in your deltoid muscle explain all of the layer and structure the needle passes through from impact to muscle

The layers that the needle passes through are;

Epidermis Dermis Subcutaneous tissue connective tissue Muscle

The epidermis is composed of flat squamous cells high in keratin content. The layer is watertight. The dermis, below the epidermis, is thicker and replenishes the cells of the epidermis. It contains the hair follicles, glands, nerves, and capillaries that serve the skin. The subcutaneous is mostly composed of fat cells and the layer has blood capillaries that serve the muscle. The connective tissue has collagen and elastin fibers that connect the skin to the muscle.