Craniofacial Muscles

Chapter 16
Spastic Facial Muscle Disorders
Juwan Park , Andrew R. Harrison , and Michael S. Lee
16.1 Introduction
Facial muscles are a group of striated muscles that, among other things, control
facial expression and are innervated by the facial nerve (CNVII). In contrast, the
nearby eyelid retractor muscles and masticator muscles are innervated by the oculomotor
(CNIII) and mandibular branch of trigeminal nerve (CNV), respectively.
Beside facial expression, facial muscles around the eyes are in charge of controlling
eye blink and eyelid closure. A blink is a temporary closure of both eyelids and
normally does not interfere with the continuity of vision. Physiologic blinking helps
keep the cornea moist to maintain a smooth refractive surface for clear vision. Re fl ex
closure of the eyelids is a spontaneous reaction to a corneal irritant. The normal
average spontaneous blink rate is 16 ± 9 times per minute.
Various dystonic or non-dystonic movement disorders, or dyskinesias, in the
facial region cause involuntary contractions of the facial muscles (Table 16.1 ),
which may be debilitating functionally and esthetically. In this chapter, we discuss
the more common facial muscle dystonias, including blepharospasm, hemifacial
spasm, and diverse conditions that cause facial spasms.
J. Park , M.D.
Department of Ophthalmology, University of Minnesota, Minneapolis, MN, USA
A. R. Harrison , M.D. (*) • M. S. Lee , M.D.
Department of Ophthalmology , University of Minnesota ,
420 Delaware Street SE , Minneapolis , MN 55455 , USA
e-mail: harri060@umn.edu
L.K. McLoon and F.H. Andrade (eds.), Craniofacial Muscles: A New Framework
for Understanding the Effector Side of Craniofacial Muscle Control,
DOI 10.1007/978-1-4614-4466-4_16, © Springer Science+Business Media New York 2013
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