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 how much middle-class families make in different states 10:36 AM ET Fri, 24 March 2017 | 00:53 The American middle class is shrinking and the median income of those considered middle class is decreasing. Nationally, the median income of middle-income households decreased from $77,898 in 1999 to $72,919 in 2014, a loss of 6%, reports Pew Research Center.