The deformity produced by a palsy of the marginal mandibular branch of the facial nerve.
It is a common misconception that damage to the marginal mandibular branch of the facial nerve causes drooping of the corner of the mouth. In fact the opposite is true, as a consideration of the anatomy confirms.
D005152:Facial Muscles / Q000033:anatomy & histology / Q000294:innervation; D005154:Facial Nerve / Q000033:anatomy & histology / Q000503:physiopathology*; D005158:Facial Paralysis / Q000503:physiopathology*; D006801:Humans; D008046:Lip