Letter charts are not only used to measure visual acuity, they are also used as targets for subjective refraction. This is the main reason distance acuity is measured more often than near acuity. At a long distance, accommodation is relaxed, so that the refraction can be more accurate.
Popliteal artery. The popliteal artery branches off from the femoral artery. It is located in the knee and the back of the leg. Its courses near the adductor canal and the adductor hiatus, distinctive open areas inside the thigh. At its far end, it splits into the anterior and posterior tibial arteries. During its course, the popliteal artery branches into other significant blood vessels.
The Popliteal Fossa. The popliteal fossa is a diamond shaped area found on the posterior side of the knee. It is the main path in which structures move from the thigh to the leg. In any anatomical area such as this, it is important to look at the borders, contents, and any clinical relevance.