Ultrasound (US) of the neck is extremely sensitive in detecting thyroid, parathyroid, and cervical lymph node pathology, and is regarded as the most complete and cost-effective imaging method for evaluating the thyroid and parathyroid glands, as well as for the diagnostic evaluation of the cervical lymph node basin. US is widely used in screening high-risk individuals, evaluation of palpable and nonpalpable thyroid nodules, needle guidance for biopsy of nonpalpable and suspicious nodules, and preoperative evaluation of the extent of thyroid neoplasms, as well as in the detection of residual, recurrent, or metastatic thyroid tumors, and in observing nonsurgical cases. It has thus become an important adjunct to the practice of head and neck surgery.