where is sentinel lymph node on the head?
<answer> The first lymph node to drain a metastatic tumor cell that drains via the lymphatic route. <context> For more information, see Head and Neck Squamous Cell Carcinoma. The sentinel lymph node (SLN) is the first lymph node to drain a metastatic tumor cell that drains via the lymphatic route. The concept of the SLN is based on the orderly progression of tumor cells within the lymphatic system.