one of several charts used in testing visual acuity. Letters, numbers, or symbols are arranged on the chart in decreasing size from top to bottom. A wall chart developed by a Dutch ophthalmologist Hermann Snellen in the 19th century, which is still used today to measure visual acuity.
Popliteal Nodes. The popliteal nodes, or popliteal lymph nodes, include six or seven nodes and are located in the legs near the knees at the popliteal fossa.They service the lower legs and feet for the lymphatic system.opliteal Nodes. The popliteal nodes, or popliteal lymph nodes, include six or seven nodes and are located in the legs near the knees at the popliteal fossa.
1. Know where the lymph nodes are located. You have the highest concentration of lymph nodes in your neck, around your collarbone, in your armpits, and in your groin. 1  Lymph nodes are present in groups, and are about the size of a pea or bean.2  Lymph nodes located in the groin are also called inguinal lymph nodes.. Know where the lymph nodes are located. You have the highest concentration of lymph nodes in your neck, around your collarbone, in your armpits, and in your groin. 1  Lymph nodes are present in groups, and are about the size of a pea or bean.