Craniofacial Muscles

The craniofacial musculature, including the extraocular muscles, muscles associated with the
auditory system, the masseter, the tongue, and the laryngeal and pharyngeal muscles, all
participate in functions that are critical to life: vision, intact of nutrition, breathing, and hearing.
Despite their critical importance, the majority of research on skeletal muscle basically has
ignored this collection of muscles. This is most likely due to their complexity in form,
development, fiber types, physiology, and disease profiles. All these make these muscles
extremely difficult to study.
Vision depends on voluntary and reflexive eye movements initiated by the oculomotor system.
The effector arm of this motor system includes the extraocular muscles and their motor neurons.
Mastication, and therefore food intake, depends on the complex movements of the masseter and
tongue musculature. The effector arm of this motor system includes the masseter and tongue
muscles and their motor neurons. Respiration, human phonation, as well as gestation, depend on
the laryngeal and pharyngeal musculature. The effector arm of these motor systems includes the
intrinsic and extrinsic laryngeal muscles and the pharyngeal muscles and their motor neurons.
Recently there has been a renewed interest in understanding the basic cell biology and
pathologies associated with these unusual skeletal muscles. This book will highlight novel
findings on the development of these muscles and their innervation, metabolic design, functional
consequences of their structural organization, and potential reasons for their differential response
to various neuromuscular diseases. In addition, critical areas for future studies will be identified. Of the approximately 640 muscles in the human body, over 10% of them are found in the craniofacial region. The craniofacial muscles are involved in a number of crucial non-locomotor activities, and are critical to the most basic functions of life, including