Thyroid and parathyroid ultrasound is a non-invasive examination that explores the morphology of the thyroid, surrounding blood vessels, and adjacent organs. It is necessary when swelling at the base of the neck is noticed, there is a sensation of a foreign body in the throat, changes in the quality and tone of the voice are observed. It is the most effective diagnostic tool for defining thyroid dysfunctions or discovering nodules. Generally, the examination is painless and non-invasive (as with other types of ultrasound, the ultrasound probe is simply placed on the area under investigation), but if the fine-needle aspiration technique is also necessary, the ultrasound probe is used as a guide.