Average column density profile of the Musca filament from the Herschel data (Cox et al. 2016), corrected to a distance of 140 pc. The blue horizontal line indicates the column density associated with the ambient cloud ( ~ 0.8 × 10²¹ cm⁻²). The dashed blue line shows the fitted Plummer profile to the column density (excluding the strands). The vertical lines indicate the location of column density excess with respect to the Plummer fit close to the filament crest, the so-called strands. The dashed horizontal black line indicates = 3 × 10²¹ cm⁻², which is the minimal column density used to define the filament crest.