We have selected 43 southern massive star-forming regions to study the spatial distribution of HNCO 4$_{04}$-3$_{03}$, SiO 2-1 and HC$_{3}$N 10-9 line emission investigate their association with dust emission. The morphology 4$_{04}$-3$_{03}$ agrees well tends originate from more compact than 2-1. divided our sources into three groups: those in Central Molecular Zone (CMZ), associated bubbles (...
