Posterolateral Neck Dissection is a surgical procedure, within the genus of neck dissection techniques, that specifically entails the removal of lymph node levels II through V along with preservation or selective resection of non-lymphatic structures such as the spinal accessory nerve, internal jugular vein, and sternocleidomastoid muscle, distinguished by its focused approach to the posterolateral cervical lymphatic basins in the management of metastatic head and neck malignancies.