Many studies on speech acoustics and production use articulatory synthesis as a framework to investigate the relationship between articulatory gestures and acoustic features. Although supraglottal articulatory models are available, usually built from vocal tract imaging acquisitions, glottal gestures are commonly modeled with simple geometric primitives which do not necessarily reflect reality. This study is a first step towards the development of a database of realistic glottal gestures which will be used to design the glottal opening dynamics in articulatory synthesis paradigms. In the first part of this paper, we present experimental measurements of glottal opening dynamics in VCV and VCCV sequences uttered by real subjects, thanks to a specifically designed external photoglottographic device (ePGG). The corpus was designed to highlight the differences in glottis opening between fricatives and stops. The existence of different patterns of glottal opening is evidenced according to the class of the consonants. A numerical study is then used to show the influence of these patterns on the production of sounds and on the coarticulation.