Thyroid nodules are the clinical manifestations of nodular goiter, and nodular goiter is the cause of thyroid nodules. Nodular goiter generally occurs in iodine-deficient areas, forming these partial or multiple thyroid nodules. Thyroid nodules are the clinical manifestations of nodular goiter; the nodules in the thyroid can be single or multiple and can cause abnormal thyroid function, although thyroid function can also be normal in the early stages. Therefore, when performing an ultrasound, if thyroid nodules are discovered, it is necessary to further assess thyroid function and dynamically track changes in the size of the thyroid nodules to determine whether it is nodular goiter.