Inguinal lymph nodes
There are two layers of inguinal lymph nodes located below the inguinal ligament, which runs from the ilium's anterior superior iliac spine (the front-most portion of the ilium, the largest pelvic bone) to the pubic bone's pubic tubercle (a small, bony projection near the bottom, center of the pelvis). They are the superficial inguinal lymph nodes and the deep inguinal lymph nodes. Lymph nodes are part of the body’s lymphatic system, which helps maintain fluid balance in the bloodstream, filters waste, and plays an important role in immune defense.
The superficial inguinal lymph nodes are located in the femoral triangle of Scarpa, an area of the upper, inner thigh. This area is formed by the sartorius muscle, the adductor longus muscle, and the inguinal ligament. There are about 10 of these lymph nodes in total that form a chain underneath the ligament. The superficial inguinal lymph nodes are located deep under Camper's fascia, one of the abdominal wall's thick layers of connective tissue, and drain into the deep inguinal lymph nodes.
The deep inguinal lymph nodes are located below the cribriform fascia — connective tissue of the upper, inner thigh — and on the medial (closer to the body’s midline) side of the femoral vein. There are about three to five of these nodes. Cloquet's node is the name of the top-most deep inguinal lymph node, which is located below the inguinal ligament.
These nodes drain first to the body's external iliac lymph nodes, second to the pelvic lymph nodes, and finally to the paraaortic lymph nodes.