Figure
3. Asymmetrical smile in a patient following left parotid to my and MRND
with sacrifice of the marginal mandibular nerve (true palsy). 3a.
Paralysis of the lip depressor with apparent drooping of the
contralateral side. 3b. Asymmetrical pouting caused by inability to
evert the left side of the lower lip
Figure 4. Asymmetrical smile of a patient following a right MRND with
preservation of the marginal mandibular nerve (i.e. pseudo-palsy). 4a.
Note weakness of the lip depressors on the right side. 4b. The function
of the marginal mandibular nerve allows bilateral eversion of the lower
lip when pouting. (i.e. pseudo-palsy)