Mastication, Deglutition, and Orofacial Anatomy

Comprehensive vocabulary flashcards covering the stages of deglutition, cranial nerve innervations, cranial bones, dental occlusion, and the musculature of the face, tongue, mandible, velum, and pharynx.

Mastication

The process of chewing, grinding, and crushing food in the oral cavity to prepare it for swallowing.

Deglutition

The act or process of swallowing, moving the bolus from the mouth into the pharynx and propelling it into the esophagus.

Oral Preparation Stage

The voluntary swallowing stage during which food is anticipated, contained by a lip seal, masticated, mixed with saliva, and formed into a cohesive bolus while the velum remains depressed for nasal respiration.

Oral Transport Stage

The voluntary swallowing stage where mastication stops, the posterior tongue drops, the anterior tongue elevates against the hard palate, and the tongue squeezes front-to-back to propel the bolus toward the faucial pillars.

Pharyngeal Stage

The involuntary swallowing stage triggered when the bolus reaches the fauces, characterized by velar elevation, hyolaryngeal elevation, laryngeal closure (airway protection), pharyngeal constriction, and upper esophageal sphincter (UES) opening.

Esophageal Stage

The involuntary, reflexive stage of swallowing wherein the bolus passes through the UES and is propelled down the esophagus to the lower esophageal sphincter (LES) via peristalsis and gravity.

Hyolaryngeal Elevation (HLE)

The upward and anterior movement executed by suprahyoid muscles lifting the hyoid and the thyrohyoid lifting the larynx, essential for epiglottic inversion and pulling open the upper esophageal sphincter.

Penetration

A swallowing dysfunction where a portion of the bolus enters the laryngeal vestibule but does not descend below the level of the true vocal folds.

Aspiration

The passage of bolus material below the level of the true vocal folds into the subglottic space and trachea.

Silent Aspiration

Infiltration of bolus material below the vocal folds into the airway without triggering a protective cough reflex, typically resulting from diminished pharyngeal and laryngeal sensation.

Valleculae

The paired anatomical recesses situated between the base of the tongue and the anterior surface of the epiglottis, which can collect residue during an abnormal swallow.

Carina

The ridge at the base of the trachea separating the openings of the primary bronchi; it is densely innervated by the vagus nerve (CN X) and acts as one of the most sensitive sites for triggering the cough reflex.

Modified Barium Swallow Study (MBSS)

A dynamic fluoroscopic swallowing examination that visualizes all stages of deglutition in real time, including the oral preparation and oral transport phases.

Fiberoptic Endoscopic Evaluation of Swallowing (FEES)

An endoscopic procedure that assesses pharyngeal swallow function directly through the nasopharynx without radiation, characterized by a momentary 'white out' during the swallow and an inability to visualize the oral preparation phase.

Perpendicular Plate of the Ethmoid

The thin bony vertical plate of the ethmoid bone that articulates with the vomer to form the bony nasal septum.

Coronal Suture

The cranial articulation between the frontal bone and the parietal bones.

Foramen Magnum

The large opening in the base of the occipital bone that transmits the spinal cord and provides articulation with the C1 vertebra.

Palatine Bones

Paired L-shaped bones that articulate with the palatine processes of the maxillae to form the posterior $\frac{1}{4}$ of the hard palate.

Class II Malocclusion

A dental malalignment characterized by mandibular molars that are retracted (positioned posteriorly) relative to the maxillary molars.

Class III Malocclusion

A dental malalignment where the mandibular molars are advanced or protruded forward relative to the maxillary molars.

Lingual Surface

The inner aspect of a tooth that faces toward and contacts the tongue.

Coarticulation

The overlapping articulatory influence of one speech sound upon another during continuous speech production.

Sjögren's Disease

An autoimmune disorder causing severe chronic dry mouth (xerostomia), impairing mastication, bolus lubrication, and speech articulation.

Orbicularis Oris

A facial sphincter muscle without bony origin innervated by CN VII that encircles the oral cavity to close, purse, and round the lips for bilabials and vowels such as /u/ and /w/.

Buccinator

A cheek muscle innervated by CN VII originating from the pterygomandibular raphe and alveolar processes that compresses the cheeks and prevents food from pocketing in the buccal cavity.

Mentalis

A facial muscle innervated by CN VII originating from the incisive fossa of the mandible that elevates and wrinkles the chin and pushes the lower lip outward (pouting).

Superior Longitudinal Muscle

An intrinsic lingual muscle innervated by CN XII that elevates the tongue tip and shortens the tongue.

Inferior Longitudinal Muscle

An intrinsic lingual muscle innervated by CN XII that depresses the tongue tip and acts to shorten or retract the tongue.

Transverse Intrinsic Muscle

An intrinsic lingual muscle innervated by CN XII originating from the median fibrous septum that narrows and elongates the tongue.

Vertical Intrinsic Muscle

An intrinsic tongue muscle innervated by CN XII originating from the mucous membrane of the dorsum that flattens the tongue down into the floor of the mouth.

Genioglossus

The prime mover of the tongue, innervated by CN XII; its anterior fibers retract the tip, posterior fibers protrude the tongue, and both act together to depress (cup) the tongue body.

Styloglossus

An extrinsic tongue muscle innervated by CN XII originating from the styloid process of the temporal bone that draws the tongue up and back, elevating the posterior dorsum.

Palatoglossus

A palatolingual muscle innervated by CN X (pharyngeal plexus) forming the anterior faucial pillar, functioning to depress the velum or elevate the back of the tongue.

Palatopharyngeus

A velopharyngeal muscle innervated by CN X (pharyngeal plexus) forming the posterior faucial pillar that depresses the velum and narrows the pharynx.

Masseter

A masticatory muscle innervated by CN V originating on the zygomatic arch and inserting into the lateral ramus and angle of the mandible to elevate the jaw.

Temporalis

A masticatory muscle innervated by CN V arising from the temporal fossa and inserting onto the coronoid process and ramus of the mandible to elevate and retract the jaw.

Lateral Pterygoid

A muscle of mastication innervated by CN V that protrudes the mandible and coordinates side-to-side grinding motions.

Mylohyoid

A muscle innervated by CN V that forms the muscular floor of the mouth, elevates the hyoid and tongue, and depresses the mandible when the hyoid is stabilized.

Levator Veli Palatini

A muscle innervated by CN X (pharyngeal plexus) originating from the petrous temporal bone that constitutes the primary bulk of the soft palate and elevates and retracts the velum to close the velopharyngeal port.

Tensor Veli Palatini

A muscle innervated by CN V whose tendon reflects around the hamulus; it tenses the soft palate and dilates (opens) the eustachian tube.

Cricopharyngeus

The inferior component of the inferior pharyngeal constrictor, innervated by CN X, which forms the upper esophageal sphincter (UES); it remains tonically contracted at rest and relaxes during deglutition.

Superior Pharyngeal Constrictor

A pharyngeal muscle innervated by CN X (pharyngeal plexus) that constricts the upper pharyngeal lumen and draws the posterior pharyngeal wall forward to form Passavant's pad.

Stylopharyngeus

A longitudinal pharyngeal muscle innervated exclusively by CN IX (glossopharyngeal nerve) that elevates and widens the pharynx during swallowing.