Patients with idiopathic facial nerve palsy have flaccid lower facial muscles, disappearance of facial lines, wider than normal cleft of the cervical latissimus muscle, and complete loss of random and synergistic movements of the facial and cervical latissimus muscles. We can make a preliminary diagnosis by their clinical manifestations. Most patients often suddenly find that one cheek movement is not working and the mouth is crooked when washing the face or rinsing the mouth in the early morning. If the facial expression muscles are completely paralyzed, the forehead wrinkles disappear, the eye fissures are enlarged, the nasolabial folds are flattened, the corners of the mouth droop, and the corners of the mouth are skewed to the healthy side when the teeth are exposed. The patient’s side cannot make movements such as forehead wrinkles, frowning, eye closure, puffing and pouting. When puffing the cheeks and whistling, the affected side of the mouth leaks air because the lips cannot be closed. When eating, food residue is often left in the gap between the teeth and cheeks on the affected side, and saliva often flows down from that side. Because the tear dots are turned inward with the lower lid, the tears do not drain normally and spill out.