Descriptions of Pleural cavity. Pleural cavity: The space enclosed by the pleura, which is a thin layer of tissue that covers the lungs and lines the interior wall of the chest cavity. Source: National Institute of Health. Pleural cavity: the cavity in the thorax that contains the lungs.
These and other retirement income streams produced an average income of $31,742 for people age 65 and older in 2012, according to a recent AARP Public Policy Institute analysis of Census Bureau data. Here's how older Americans are paying their bills in retirement:
Why Pensions are Important: Sources. 1  The average monthly Social Security benefit paid to retired workers in 2015 is $1,335.97, or $16,031.64 a year.