Facial nerve an incorrectly placed dental local-anesthetic (Inferior alveolar nerve block). Although giving the appearance of a hemi-plegic stroke, effects dissipate with the drug. When the facial nerve is permanently damaged due to a birth defect, trauma, or other disorder, surgery including a cross facial nerve graft or masseteric facial nerve transfer may be performed to help regain facial movement. Facial nerve decompression surgery is also sometimes carried out in certain cases of facial nerve compression. Voluntary facial movements, such as wrinkling the brow, showing teeth, frowning, closing the eyes tightly (inability to do so is called lagophthalmos) , pursing the lips
Facial motion capture deformable surface models and other techniques to track the desired facial features from frame to frame. This technology is much less cumbersome, and allows greater expression for the actor. These vision based approaches also have the ability to track pupil movement, eyelids, teeth occlusion by the lips and tongue, which are obvious problems in most computer animated features. Typical limitations of vision based approaches are resolution and frame rate, both of which are decreasing as issues as high speed, high resolution CMOS cameras become available from multiple sources. The technology for markerless face tracking is related to that in a