The glottal source signal conveys very important information about the speech emotions. For example, source parameters have been successfully used in applications of recognition, transformation and synthesis of speech emotions. Often the source parameters are extracted from the speech signal only, without estimating the glottal source component, mainly because of the difficulty to separate this component from speech. This paper aims to improve the knowledge about the acoustic correlates of emotions by using accurate measurements of shape parameters of the glottal pulse. To achieve this, the most relevant glottal pulse instants are estimated using a semi-automatic method based on the analysis of both the electroglottographic and speech signals. Additional source parameters, the strength of excitation and harmonic-to-noise ratio, are also estimated from the speech signal, for comparison with the glottal parameters in our experiment. The average results of analysis of the source parameters show that they generally have a strong correlation with the set of emotions using neutral as reference: angry, disgusted, happy, sad, scared, and surprised. A possible application of this study is to derive parameter scale factors from the average measurements of the glottal parameters for speech emotion transformation.