Most commonly, patients describe acute tenderness in the buttock and sciatica-like pain down the back of the thigh, calf and foot. Typical piriformis syndrome symptoms may include: 1  A dull ache in the buttock. 2  Pain down the back of the thigh, calf and foot (sciatica).
We think of ice as snowflakes, ice cubes, snow cones, and dangerous patches on the sidewalk. Scientists have many different ways of categorizing ice too! There are actually fourteen types of ice that exist in different environments.
Only ordinary hexagonal ice is less dense than the liquid. Under increasing pressure, ice undergoes a number of transitions to other allotropic forms with higher density than liquid water, such as ice II, ice III, high-density amorphous ice (HDA), and very-high-density amorphous ice (VHDA).