Paralysis of facial muscles in leprosy patients with lagophthalmos.

The objective of the study was to determine the pattern of involvement of facial muscles in lagophthalmos. Fifty-seven patients with lagophthalmos were examined to assess the degree of paralysis of facial muscles. Eighty-one percent of the patients with lagophthalmos had involvement of at least one other muscle group. In patients with lagophthalmos with a gap at mild closure of 5 mm or more, 27 of 30 (90%) had involvement of at least one other facial muscle. In lepromatous leprosy the pattern of involvement was symmetrical and "patchy," the right and left sides being affected equally. In tuberculoid leprosy, the ipsilateral muscles were more often involved, which is the pattern of involvement of a nerve trunk. The upper and lower facial muscles were affected in the same proportion. Hence, on clinical grounds, there is little support for the often postulated statement that the superficial course of the facial nerve above the zygomatic bone is decisive for exclusive paralysis of the zygomatic branch of the facial nerve.