Neuro Swallow (09-14-26 *M) Anatomy and Physiology of Swallowing: Oral Cavity, Pharynx, and Larynx

Vocabulary flashcards covering the key structures, cavities, cartilages, and physiological mechanisms involved in healthy swallowing as presented in the lecture.

Head of the bolus

The leading edge or foremost part of the bolus as it travels during swallowing.

Tail of the bolus

The trailing rear end of the bolus where driving pressure is applied to move it forward and downward.

Positive pressure

The pushing force applied to the tail of the bolus—comparable to squeezing the end of a toothpaste tube—that propels the bolus through the oral cavity and pharynx.

Negative pressure

The suction force created when drinking through a straw that pulls liquid upward rather than pushing it.

Mastication

The physiological process of chewing to physically manipulate and prepare food within the oral cavity.

Hard palate

The rigid bony roof of the mouth that forms the anterior two-thirds of the superior border of the oral cavity.

Soft palate

The muscular posterior one-third of the palate that rests lowered during breathing and elevates during swallowing to seal off the nasopharynx.

Mylohyoid muscle

The largest muscle located under the chin area that constitutes the floor of the mouth and forms the inferior border of the oral cavity.

Mandible

The lower jaw; identified as the only movable bone in the oral region, which allows mouth opening and mastication.

Maxilla

The rigid upper jaw bone that forms part of the superior border of the oral cavity and the anterior hard palate.

Anterior facial pillars

The forward arches shaped like the letter M in the oral cavity that serve as a critical anatomical landmark for swallow initiation.

Posterior facial pillars

The muscular arches located behind the anterior facial pillars; the palatine tonsils are situated between the anterior and posterior pillars.

Sulcus (plural: sulci)

The anatomical space formed between the alveolus (teeth and gums) and the cheeks (lateral or buccal sulcus) or lips (anterior or labial sulcus) where food residue often collects.

Muscular hydrostat

A specialized biological structure comprised entirely of muscles without skeletal bony support, exemplified by the human tongue.

Oral tongue

The visible anterior portion of the tongue that operates under volitional (voluntary) neural control and is active during speech and the oral phase of swallowing.

Base of the tongue (BOT)

The posterior, pharyngeal portion of the tongue that operates predominantly under involuntary neural control during swallowing.

Sublingual salivary glands

Bilateral salivary glands located underneath the tongue that contribute to bolus formation and chemical digestion.

Submandibular salivary glands

Bilateral salivary glands situated beneath the mandible that wrap around the mylohyoid muscle.

Xerostomia

Severe dry mouth caused by reduced or absent saliva production, frequently occurring as a side effect of radiation therapy for head and neck cancers.

Nasopharynx

The superior region of the pharynx located directly behind the nasal cavity.

Oropharynx

The middle region of the pharynx located directly behind the oral cavity.

Hypopharynx

Also called the laryngopharynx; the lowermost division of the pharynx connecting to the esophagus, splitting anteriorly into the larynx and trachea.

Posterior pharyngeal wall (PPW)

The muscular back wall lining the pharyngeal tube that assists in squeezing and propelling the bolus downward.

Vallecular space (Wallicular space)

Bilateral pharyngeal pockets situated between the base of the tongue and the epiglottis where swallowed material commonly pools as residue.

Piriform sinuses

Bilateral recesses situated at the inferior boundary of the pharynx right above the esophageal entrance where bolus residue frequently collects.

FEES

Fiberoptic endoscopic evaluation of swallowing; an assessment method where an endoscope is inserted transnasally to view the pharynx and larynx from above.

Whiteout period

A brief obstruction of the camera view during a FEES examination caused by epiglottic movement and pharyngeal closure during the swallow itself.

Hyoid bone

A mobile, hook-like anchor bone that is not articulated with any other bone; it provides attachment for numerous muscles and moves upward and forward during swallowing.

Pharyngeal esophageal segment (PES)

Also termed the upper esophageal sphincter (UES); the muscular opening between the pharynx and esophagus that stays closed at rest and opens briefly during swallowing.

Glottis

The anatomical opening or space located directly between the true vocal folds.

Supraglottic area

The anatomical division of the larynx situated above the level of the glottis.

Subglottic area

The anatomical division of the larynx situated below the level of the glottis.

Thyroid cartilage

The largest, unpaired, shield-shaped cartilage of the larynx featuring the prominent thyroid notch (Adam's apple).

Cricoid cartilage

A complete ring-shaped cartilage located directly below the thyroid cartilage that is narrower anteriorly and larger posteriorly.

Epiglottis

A flexible, leaf-shaped elastic cartilage attached to the anterior thyroid cartilage that projects over the pharynx and deflects during swallowing to protect the airway.

Arytenoid cartilages

Paired, pyramid-shaped cartilages that rest on the posterior cricoid cartilage and tilt to regulate vocal fold closure for phonation and airway protection.

Facial Skeleton

The anterior skeletal framework of the skull that forms the structural support for the organs of mastication, speech, respiration, and the muscles of facial expression.

Cranium

The portion of the skull composed of rigidly joined bones that houses and protects the brain.

Mylohyoid Muscle

The muscle that forms the floor of the mouth and constitutes the inferior anatomical boundary of the oral cavity.

Sulcus (Oral)

The anatomical pocket or space formed between the alveolus and the cheek or lip musculature, divided into anterior (labial) and lateral (buccal) spaces located both superiorly and inferiorly.

Muscular Hydrostat

A biological muscular organ that lacks rigid skeletal support and allows for fine, intricate, three-dimensional movements (such as the tongue and the pharynx).

Oral Tongue

The anterior functional division of the tongue (comprising the tip, blade, front, center, and back) ending at the circumvallate papillae; operates under cortical/voluntary neural control during speech and the oral stage of swallowing.

Base of Tongue (BOT)

The posterior functional division of the tongue extending from the circumvallate papillae down to the hyoid bone; active during the pharyngeal phase under involuntary control coordinated by the medullary swallow center in the brainstem.

Lingual Stripping

The sequential propulsive movement of the tongue pressing against the palate to drive the bolus posteriorly through the oral cavity.

Deciduous Dentition

The initial set of primary baby teeth, comprising a full set of 20 teeth present from the first year to 7 years of age.

Permanent Dentition

The adult set of teeth, comprising a full set of 32 teeth divided into incisors (slice/bite), canines (puncture), premolars (crush/grind), and molars (crush/grind).

Parotid Gland

The largest bilateral salivary gland, positioned anterior to the ear and superficial to the masseter muscle.

Sublingual Gland

The bilateral salivary gland situated beneath the tongue in the floor of the mouth.

Submandibular Gland

The bilateral salivary gland located medial to the mandible that wraps around the posterior border of the mylohyoid muscle.

Pharynx

A muscular tube functioning as a muscular hydrostat that propels the bolus through the pharyngeal stage of swallowing; connects superiorly with the Eustachian tube and adenoids in the nasopharynx.

Pyriform Sinus

A bilateral recess or space situated in the hypopharynx lateral to the laryngeal opening through which food and liquids travel.

Hyoid Bone

The only bone in the human body not articulated with any other bone; serves as a vital muscular attachment site and structural anchor for the tongue and laryngeal complex.

Velum (Soft Palate)

The muscular posterior continuation of the hard palate; rests in a lowered position for nasal breathing and elevates during swallowing to seal the velopharyngeal port and prevent nasal regurgitation.

Laryngeal Vestibule

The superior anatomical entryway or opening leading directly into the laryngeal cavity.

Laryngeal Ventricle

The lateral space or sinus located between the false (ventricular) vocal folds and the true vocal folds.

Thyroid Cartilage

An unpaired, shield-shaped hyaline cartilage consisting of two lateral laminae that meet anteriorly, forming the thyroid notch, angle, oblique line, and superior and inferior horns.

Thyroid Angle

The angle at which the two thyroid laminae join anteriorly, demonstrating sexual dimorphism: approximately $90^\circ$ in adult males (forming the visible Adam's apple) and $120^\circ$ in adult females.

Cricoid Cartilage

An unpaired, complete signet ring-shaped laryngeal cartilage located immediately superior to the trachea, consisting of a narrow anterior arch and a broad posterior lamina.

Epiglottis

An unpaired, leaf-shaped elastic cartilage attached to the inner surface of the thyroid cartilage that inverts during swallowing to help protect the airway.

Arytenoid Cartilages

Paired, pyramid-shaped laryngeal cartilages perched atop the posterior lamina of the cricoid cartilage, each possessing three distinct landmarks: an apex, a muscular process, and a vocal process.

Vallecula

The bilateral pocket or recess located in the hypopharynx between the base of the tongue and the anterior surface of the epiglottis.

Carina

The cartilaginous ridge located at the inferior base of the trachea where it bifurcates into the left and right main bronchi.

Esophagus

A muscular tube measuring $18\text{ to }25\,\text{cm}$ in adults, transitioning from striated muscle superiorly to smooth muscle inferiorly; positioned directly posterior to the trachea, sharing the tracheoesophageal party wall.

Upper Esophageal Sphincter (UES)

Also called the pharyngoesophageal segment (PES); a functional muscular valve composed of the inferior pharyngeal constrictor, cricopharyngeus muscle, and proximal esophagus that maintains tonic contraction at rest and relaxes/opens to allow bolus passage.

Lower Esophageal Sphincter (LES)

The muscular sphincter located at the gastroesophageal junction that maintains tonic contraction at rest to prevent reflux and relaxes to permit bolus entry into the stomach.

Peristalsis

Coordinated, involuntary sequential muscular contractions along the esophageal body that transport the ingested bolus from the upper esophageal sphincter to the lower esophageal sphincter.

Pediatric Swallowing Anatomy

The structural arrangement in infants characterized by no dentition, flatter palate, buccal sucking pads, relatively large tongue filling the oral cavity, elevated hyoid and larynx, epiglottic contact with the soft palate, and obligate nasal breathing until approximately 6 months of age.

Logemann's Tubes and Valves Concept

A biomechanical swallowing model conceptualizing the aerodigestive tract as a system of tubes (oral and pharyngeal cavities) and valves (lips, tongue, velopharyngeal port, larynx, UES, LES) whose primary objective is generating pressure differentials to propel a bolus.