Lymph nodes in the head and neck region can become enlarged due to infection, malignancy, or systemic disease. The document outlines the key lymph node groups in the head and neck area, including cervical, supraclavicular, axillary, and inguinal nodes. It provides anatomical landmarks and describes how to examine the lymph nodes by palpation, checking each area with moderate pressure using the fingertips. The cervical nodes are most commonly enlarged due to upper respiratory infections.