Craniofacial Muscles

Chapter 15
Facial Nerve Innervation and Facial Palsies
Adriaan O. Grobbelaar and Alex C. S. Woollard
15.1 Introduction
There are a myriad of causes of facial palsy. Identifying the etiology in each case is
of vital importance to the choice of management pathway, either as an emergency
or in terms of long-term intervention. Most patients at the time of presentation are
convinced that they are suffering from either a stroke (50%), an intracranial tumor
(25%), or do not know but are nonetheless anxious (25%) (Peitersen 2002 ) . In a
review of the literature, Schaitkin and May identi fi ed over 100 possible diagnoses
but the overwhelming majority (50–66%) of cases were Bell’s palsies (Schaitkin
et al. 2000 ) . The dif fi culty of this diagnosis of idiopathic paralysis is that it is one of
exclusion. Any case of new onset palsy must be thoroughly examined, and the history,
as always, is vital in ascertaining the cause. The onset, progression, concurrent
symptoms, and localization all assist the physician in deciding what further investigations
are required.
Whatever the cause of the facial palsy, this is a devastating condition. The complete
or partial loss of function of the seventh cranial nerve results in a spectrum of
both functional and esthetic problems that plague the lives of sufferers. The
American Medical Association Guide to the Evaluation of Permanent Impairment,
which rates disabilities on a scale of “percentage of whole body impairment,” scores
unilateral facial palsy as 10–15% and bilateral as 30–45% (Cocchiarella and
Andersson 2001 ) . Communication, social interaction, vision, eating, and drinking
can all be affected. In children, it is a detrimental to their development and leaves
them introverted and shy. The lack of subcutaneous muscular tension exacerbates
the aging process such that the affected side of the face falls, causing long-term
problems with eye and mouth closure. Tears can run from the loose lower lid and
A. O. Grobbelaar (*) • A. C. S. Woollard
Institute for Plastic Surgery Research and Education , Royal Free Hospital ,
Pond Street , London NW3 2QG , UK
e-mail: aog@talk21.com
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_15, © Springer Science+Business Media New York 2013
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