Hilum of lymph node

The hilum of a lymph node is a central area where blood vessels and efferent lymphatic vessels enter and exit the lymph node.

on ultrasound it is typically characterized by a linea, echogenic structure, which is continuous with the surrounding fat. The hilum contains nodal vessels and is often visible as a hyperechoic area due to the presence of fatty tissue, known as the fatty hilum. The hilum's vascularity can be assessed using Doppler sonography.