Swallow Process Flashcards
Lip Closure
Swallow begins once the bolus is present in the oral cavity, the lips prevent escape anteriorly and generate intra-oral pressure that leads to efficient transport. The primary contributor is the orbicularis oris muscle which is innervated by the facial nerve (VII).
Tongue Control during Bolus Hold
is the elevation of the anterior, lateral, and posterior margins of the tongue to the hard and soft palate. The intrinsic muscles of the tongue (superior longitudinal, inferior longitudinal, transverse, and vertical) are innervated by the (CN XII) and shape the tongue to hold the bolus. The tensor veli palatini (CN V) stiffens the soft palate to facilitate posterior oral containment. The extrinsic muscle of tongue, palatoglossus, is innervated by (CN X) and raises the back of the tongue closing the entry to the oropharynx.
Bolus Preparation/Mastication
The bolus is manipulated and mixed with saliva. The muscles of mastication are innervated by the (CN V) and include the masseter, medial pterygoid, and temporalis which elevate the mandible to close the mouth, and the lateral pterygoid which supports side-to-side movement. The intrinsic muscles of the tongue move the bolus to the teeth for chewing and bolus formation.
Bolus transport/ lingual motion
To propel the bolus into the pharynx, the tongue moves in an anterior-posterior, brisk, and coordinated motion that applies pressure to the bolus tail. The intrinsic muscles of the tongue move the bolus posteriorly and maintain the cohesive shape of the bolus.
Oral residue
is a sign of a physiologic impairment with lingual motion regarding the intrinsic muscles of the tongue.
Initiation of the pharyngeal swallow
is a motor response to sensory input (tongue movement, presence of bolus, taste, and temperature), signaled by the first brisk movement of the hyoid. The motor response includes soft palate elevation and retraction, laryngeal elevation, anterior hyoid movement, epiglottic inversion, laryngeal vestibule closure, pharyngoesophageal segment opening, and tongue base retraction. The faucial arches and back of the tongue are innervated by the pharyngeal branch of the CN IX. The base of the tongue, vallecula, epiglottis, pharyngeal wall, aryepiglottic folds, ventricular folds, arytenoids, vocal folds, and pyriform sinuses are innervated by the internal branch of (CN X).
Soft palate elevation
the soft palate engages in elevation and retraction by the levator veli palatini muscle which is innervated by the vagus nerve to prevent retrograde flow of the bolus into the nasopharynx.
Laryngeal elevation
The first line of airway protection is elevation of the larynx. The thyrohyoid muscle elevates the thyroid cartilage and is innervated by (C1). The long pharyngeal mucles (stylopharyngeus muscle innervated by CN IX, the slpingopharyngeus and palatopharyngeus muscles are innervated by CN X) contribute to laryngeal elevation.
Anterior hyoid excursion
Signals the height of the pharyngeal swallow which is attributed to the suprahyoid muscle the geniohyoid muscle which is innervated by C1.
Epiglottic movement
The first stage of epiglottic inversion is achieved by laryngeal elevation; the second stage of complete inferior displacement is achieved by anterior hyoid excursion (geniohyoid C1, mylohyoid CN V, and digastricus anterior belly CN V) and the retraction of the tongue base.
Laryngeal vestibule closure
Early closure of the laryngeal inlet (retracted by BOT muscles: styloglossus innervated by CN XII and palatoglossus CN X) occurs during laryngeal elevation; late closure occurs at the height of anterior hyoid displacement. The intrinsic muscle of the larynx (thyroarytenoid, lateral cricoarytenoid muscle, and interarytenoid muscle) are innervated by the CN X and are associated with laryngeal elevation and adduction of vocal folds and ventricular folds.
Pharyngeal stripping wave
the stripping action of the pharynx is achieved by contraction of the pharyngeal constrictor muscles (superior constrictor muscle, middle constrictor muscle, and inferior constrictor muscle) which are innervated by the CN X and assist with pharyngeal clearance of bolus tail through contractions superiorly to inferiorly to cause contrast material on the PPW.
Pharyngeal contraction
The combined action of the long pharyngeal muscles shortening and widening and the pharyngeal constrictor muscles applying pressure to the bolus tail through sequential contractions superiorly to inferiorly.
PES opening
The onset of the pharyngeal swallow facilitates the opening of the pharyngoesophageal segment by relaxing the cricopharyngeus muscle which is innervated by CN X and contracted at rest but relaxes through biomechanical forces applied to the hyolaryngeal complex and phayrnx.
Tongue base retraction
The tongue proceeds in a posterior direction to the medial pharyngeal wall assisting in shielding the laryngeal inlet and plays a role in pharyngeal clearance, which is retracted by the extrinsic muscles of the tongue (styloglossus muscle is innervated by the CN XII and the palatoglossus is innervated by CN X).
