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.
The PewResearch Center suggests that the middle income range is 75 percent to 150 percent of the median income. This would make the middle class income range $37,675 to $75,350. To most, this range seems small, and surveys conducted by the PewResearch Center find that many who fall outside this range still consider themselves middle class.