Figure 9. Multiple nodes– secondary nodes versus multiple sentinel nodes. (a) Frontal image from a 26-year-old female with a melanoma on the right calf (injection site not shown) demonstrating nodal uptake in three right inguinal nodes. The right thigh lymphatic vessel drains directly into the lowest node (arrow) which is the sentinel node. Lymph subsequently drains to the two further nodes and these are therefore secondary nodes and need not be marked. (b) Frontal image from a 46-year-old male with a left calf melanoma (injection site not demonstrated) showing two separate lymphatic vessels (arrows) draining into two left inguinal nodes, which are therefore both sentinel nodes and should both be marked for sampling.