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.
1 Popliteal artery: A branch of the femoral artery, the popliteal artery branches further to supply blood to the knee, thigh, and calf. 2  It ends at the anterior and posterior tibial arteries. 3  Posterior tibial artery: This branch of the popliteal artery supplies oxygenated blood to the leg and sole of the foot.n Depth: Vessels. Once blood is oxygenated in the lungs, it returns to the heart and is then pumped throughout the body. A web of blood vesselsâarteries, veins, and capillariesâcirculate blood to organs, muscles, bones, and other tissues.