Pleural cavity: the cavity in the thorax that contains the lungs. Source: WordNet 2.1. Pleural cavity: cavity within the thoracic cavity consisting of the space between the parietal and visceral pleura; normally contains a capillary layer of serous fluid that lubricates the pleural surfaces.
Middle Class Average Income Range: $36,000 â $57,657. On a narrow view, a middle class family is said to have a mean average household income of $46,829 on a yearly basis. The numbers reflected on the 2010 Census showed that middle class average yearly income range from $36,000 â $57,657. Such figures fall on the third quintile.
As of 2013, anyone earning between $40,187 and $65,501 is in the middle 20% of households. Anyone earning between $20,900 and $105,910 is in the middle 60% of households. One popular rule of thumb holds that anyone earning 25% more or 25% less than the median is within the middle class. By that metric, households earning between $38,954 and $64,924 are middle-class.