After the stratosphere come the mesosphere and thermosphere. First is the mesosphere, which extends upward to 50 miles above the surface. After the mesosphere, we have our layer thermosphere, which extends from about 50 miles above the surface of Earth to about 600 miles above our planet. Beyond that is the exosphere, which is the layer that turns into outer space at the edge. What Do We Know About the Mesosphere?
Calf and hamstring pain can be caused by sciatica, a condition in which your sciatic nerve is irritated. A pulled hamstring muscle near your knee joint or a pulled calf muscle near the knee induces pain. The bursas lubricating and cushioning your knee joint and the pelvic attachment of your hamstring muscle can become irritated and swollen, causing pain.
But there are other reasons your calf may suddenly cause you pain. Namely cramps and Achilles injuries: Calf Muscle Cramp -A far less severe, but often painful, cause of calf pain is the muscle cramp or spasm. This involuntary contraction of a muscle is short-lived, but in may be so strong that it causes a bruise.