The mechanism causing breaks in the radial surface brightness distribution of spiral galaxies is not yet well known .
Despite theoretical efforts , there is not a unique explanation for these features and the observational results are not conclusive .
In an attempt to address this problem , we have selected a sample of 34 highly inclined spiral galaxies present both in the Sloan Digital Sky Survey and in the Spitzer Survey of Stellar Structure in Galaxies .
We have measured the surface brightness profiles in the five Sloan optical bands and in the 3.6 \mu m Spitzer band .
We have also calculated the color and stellar surface mass density profiles using the available photometric information , finding two differentiated features : an innermost break radius at distances of \sim 8 \pm 1 kpc [ 0.77 \pm 0.06 R _ { 25 } ] and a second characteristic radius , or truncation radius , close to the outermost optical extent ( \sim 14 \pm 2 kpc [ 1.09 \pm 0.05 R _ { 25 } ] ) of the galaxy .
We propose in this work that the breaks might be a phenomena related to a threshold in the star formation , while truncations are more likely a real drop in the stellar mass density of the disk associated with the maximum angular momentum of the stars .