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.
Here's the breakdown of how much you have to earn each year to qualify as middle-income, depending on the size of your family: Household of one: $24,042 to $72,126. Household of two: $34,000 to $102,001. Household of three: $41,641 to $124,925. Household of four: $48,083 to $144,251.