Phonetically a very difficult case; diverse phonetic processes are likely due to different patterns of compatibility of root consonants in various languages.
Akkadian
bamtu - chest, front of the chest
(CAD B 78, AHw. 101)
Clear-cut cognates with anatomic meaning are found in Ugr. bmt “back, rump, loin” and Hbr. *bōmät “back” (HALOT 136).