The aim of this project is to develop and perform a first evaluation of a software, based on the active contour, which automatically computes the cross-section area of the internal jugular veins through a sequence of 90 ultrasound images. The software is intended to be useful in future research in the field of intra cranial pressure and its associated diseases. The biomechanics of the internal jugular veins and its relationship to the intra cranial pressure is studied with ultrasound. It generates data in the form of ultrasound sequences shot in seven different body positions, supine to upright. Vein movements in cross section over the cardiac cycle are recorded for all body positions. From these films, it is interesting to know how the cross-section area varies over the cardiac cycle and between body positions, in order to estimate the pressure. The software created was semi-automatic, where the operator loads each individual sequence and sets the initial contour on the first frame. It was evaluated in a test by comparing its computed areas with manually estimated areas.  The test showed that the software was able to track and compute the area with a satisfactory accuracy for a variety of sequences. It is also faster and more consistent than manual measurements. The most difficult sequences to track were small vessels with narrow geometries, fast moving walls, and blurry edges. Further development is required to correct a few bugs in the algorithm. Also, the improved algorithm should be evaluated on a larger sample of sequences before using it in research.