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.
Small, bean-shaped structures called lymph nodes are found near the lymphatic vessels. There are about 600 lymph nodes throughout the body, some in deep tissues and others closer to the skin. Clusters of nodes are found in the neck, armpits, abdomen and groin.Other nodes are found in the chest, arms, and legs.Those in the neck, underneath the arms, and in the groin can be felt with the fingers.here are about 600 lymph nodes throughout the body, some in deep tissues and others closer to the skin. Clusters of nodes are found in the neck, armpits, abdomen and groin. Other nodes are found in the chest, arms, and legs. Those in the neck, underneath the arms, and in the groin can be felt with the fingers.