Lipoatrophia semicircularis is a medical condition in humans, commonly known as ribbed thighs. It consists of a semicircular zone of atrophy of the subcutaneous fatty tissue located mostly on the front of the thighs. Skin and underlying muscles remains intact. Semicircular lipoatrophy mainly affects office workers. The ribs in the thighs are typically between 2 and 4 cm high and are typically located at about 72 cm above the ground, which is the standard height of office furniture. Cause
It is not yet clear what exactly causes semicircular lipoatrophy. Some hypotheses are that it is caused by localized pressure or by electromagnetic fields. Diagnosis
Treatment
See also
Lipodystrophy
List of cutaneous conditions

References


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Current records may significantly underestimate the frequency of strong (EF2-EF3) and violent (EF4-EF5) tornadoes, as damage-based intensity estimates are limited to structures and vegetation that a tornado impacts. A tornado may be much stronger than its damage-based rating indicates if its strongest winds occur away from suitable damage indicators, such as in an open field. Outside Tornado Alley, and North America in general, violent tornadoes are extremely rare. This is apparently mostly due to the lesser number of tornadoes overall, as research shows that tornado intensity distributions are fairly similar worldwide. A few significant tornadoes occur annually in Europe, Asia, southern Africa, and southeastern South America. Climatology
The United States has the most tornadoes of any country, nearly four times more than estimated in all of Europe, excluding waterspouts. This is mostly due to the unique geography of the continent. North America is a large continent that extends from the tropics north into arctic areas, and has no major east–west mountain range to block air flow between these two areas. In the middle latitudes, where most tornadoes of the world occur, the Rocky Mountains block moisture and buckle the atmospheric flow, forcing drier air at mid-levels of the troposphere due to downsloped winds, and causing the formation of a low pressure area downwind to the east of the mountains. Increased westerly flow off the Rockies force the formation of a dry line when the flow aloft is strong, while the Gulf of Mexico fuels abundant low-level moisture in the southerly flow to its east.