Reconstructive surgery for facial nerve palsies is not recommended beyond two to three years after a degenerative facial nerve lesion. Since the time course of muscle atrophy is variable, this timeline is a rough guideline. The only assessment method currently used is needle electromyography (EMG). This paper describes a fast, non-invasive, and reliable method to evaluate the condition of the facial muscles and the degree of atrophy. The authors used a 3D ultrasonographic (US) acquisition system driven by a motorised linear mover combined with conventional US probe to acquire 3D data sets of several facial muscles on both sides of the face in a healthy subject and in seven patients with different types of unilateral degenerative facial nerve lesions. The US results were correlated to the duration of palsy and the EMG results. The facial muscles on the side of the paralysis, with the exception of the frontal muscle, were much smaller than on the healthy side in patients with severe facial nerve injuries. This new 3D ultrasonographic tool seems to be a promising innovation for the quantitative evaluation of facial muscles in patients considering reconstructive surgery or conservative treatment.