The phrase "inch bust" refers to the measurement of a person's chest, specifically the circumference around their bust or the fullest part of their chest. Full definition
[10] Pattern companies sold sheath cuts up to size 22 1/2 and 41 inch bust size. (en.wikipedia.org)
Gianni Versace 1990s Couture Alpaca and Wool Runway and Ad Campaign Suit Labelled size 38 Jacket 32 inch Bust Skirt 24 Inch Waist Excellent Vintage Condition (1stdibs.com)
But let's try: Give this young woman the hands - down award for best impression of Bela Lugosi while hampered by a 38 - inch bust line. (washingtonpost.com)