 The hilum is an indent on the concave surface of the lymph node where lymphatic vessels leave and blood vessels enter and leave.Lymph enters the convex side of a lymph node through multiple afferent lymphatic vessels and from here flows into a series of sinuses.After entering the lymph node from afferent lymphatic vessels, lymph flows into a space underneath the capsule called the subcapsular sinus, then into cortical sinuses.