Craniofacial Muscles

9 Structure and Function of the Laryngeal and Pharyngeal Muscles
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Fig. 9.8 High-resolution manometry data showing pressure changes across time and spatial position
with 5 mL bolus swallow using head turn. Upper esophageal sphincter is plot’s upper border and
plot’s lower border is nasopharynx. Used with permission from McCulloch et al. ( 2010 )
weakening of the pharynx (Belafsky et al. 2010 ) . Maneuvers such as the effortful
swallow have been found to elicit longer UES relaxation durations and improve
swallow function impacted by CP dysfunction (Hiss and Huckabee 2005 ) . Recently,
Belafsky ( 2010 ) determined that manual control of the UES was possible by placing
a traction suture around the cricoid cartilage’s anterior edge and speci fi cally
placing an implant near the cricoid cartilage. This implant would then open up the
UES when an external magnet was placed on the neck. This Swallow Expansion
Device (SED) reportedly improved UES opening in patients with oropharyngeal
dysphagia. Testing of the suture in sheep and cadavers before implantation into
humans did not result in any cricoid abrasion but did improve opening of the UES
by over 1 cm and prevent aspiration in an ovine model. Thus, there is the possibility
of using novel devices in the treatment of dysphagia related to CP muscle dysfunction
as new technology emerges.
While pharyngeal muscles primarily subserve deglutition, there is some evidence
that they may be active under some respiratory conditions. These muscles are not
typically recruited during rest breathing, but there have been reports of pharyngeal
muscle activity with airway obstruction and high respiratory drive (van Lunteren
and Strohl 1986 ) . Likewise, the superior constrictor muscle may adjust air fl ow
resistance during expiration (Collett et al. 1986 ) .