Normal Swallow: From start to finish

Oral Phase (volitional/Voluntary)

Oral Preparation: Before actual Swallow

• Preparation of Bolus: Break down to form a cohesive bolus:

  • lingual manipulation: can break material down that does not require mastication

  • Break down bolus with muscles of mastication: mandible depresses→ to get food in our mouth+ for when we are chewing. Mandible also elevates when chewing!

  • Mix bolus with saliva from salivary glands to moisten food and form into a safe consistency and shape.

    • SALIVA: BREAKS DOWN FOOD SO WE CAN FORM A COHESIVE BOLUS*****

  • Avoid anterior bolus loss

  • Avoid Pocketing: Get out of anterior and lateral sulky by lateralizing the tongue. also tension of buccinator to avoid buccal pocketing.

• Hold Bolus:

  • In a specific tongue position to avoid posterior loss

  • velo-lingual/palato-glossal seal: seals tongue posterior to pharyngeal wall that prevents food or liquid from falling prematurely into the pharynx while normal nasal breathing continue

  • Push bolus posteriorly with our tongue

  • avoid anterior bolus loss: lip seal- Orbicular Oris

• Overall: requires adequate tongue control to hold bolus and avoid premature posterior spillage and labial seal to avoid anterior labial escape. also tension from buccal muscles to prevent pocketing

Oral phase- SULCI

Anterior and Lateral sulci; sight of pocketing. concerned about sulci because of residue

• check for pocketing, especially in stroke patients with weakness on one side

Oral phase- Rotary Mastication

jaw moves laterally, downward, and across midline, upward to close. Food is transferred from side to side and is ground my molars

weak mastication: munching→ only up and down movement of the jaw; often modify diets temporarily for adults who do this in TX

Oral phase: Palato-glossal SEAL

seals tongue posterior to pharyngeal wall until bolus ready to be transported posteriorly.

Oral phase- Intrinsic tongue muscles

All innervated by the hypoglossal nerve; superior/inferior longitudinal, transverse, vertical.

These muscles dynamically change shape of tongue necessary for Oral phase of swallowing: e.g., cupping edges to hold liquid bolus (avoid posterior spillage before swallow trigger can be initiated, holding bolus of surface of tongue before that transport), pressing against hard palate to allow the bolus to roll back posteriorly toward oropharynx, etc.

Oral phase- Lingual manipulation

• moves bolus in mouth and makes sure we get food out of anterior and lateral sulci

Oral phase: lingual propulsion

• once bolus ready to be transported, pallotoglossal seal breaks and

• base of tongue forms ramp posteriorly

• bolus pushed against hard palate

• pressure behind tail

• velum raises to close of nasopharyngeal passageway/velopharyngeal port-closure →prevents nasal regurgitation!!

• bolus is then propelled back

Pharyngeal Phase (mostly involuntary)

• Controlled by brainstem: brainstem + pharyngeal phase go hand in hand; patients with lesion usually have significantly impaired pharyngeal phase. Brainstem lesion/stroke= higher likelihood of dysphagia!→ swallowing center→ coordinates muscles and timing for swallow.

• As the bolus moves posteriorly, it stimulates sensory receptors (NTS in medulla and Nucleus Ambiguous) to produce the pharyngeal swallow**

• Velopharyngeal Closure: Soft palate elevates and moves to close off the nasopharynx (so we don’t have nasal regurgitation)

• Airway Protection:

  • Hyolaryngeal Elevation & Excursion: The hyoid bone and larynx are pulled upward and forward (anteriorly and superiorly) by suprahyoid and long pharyngeal muscles. This movement tucks the larynx safely underneath the tongue base

  • Inversion of the Epiglottis: Covers laryngeal vestibule to protect airway

  • VFs adduct tightly to seal off trachea (true and false)

  • Breathing temporarily stops: Sleep Apnea; swallowing occurs during early or mid exhalation: breath in→ start to breath out→ Swallow→ continue exhaling; helps prevent inhaling material into the airway (aka aspiration)

  • Pharyngeal Contraction: The pharyngeal constrictor muscles contract sequentially from top to bottom, creating pressure behind the bolus, helping it push down the esophagus. There is higher pressure behind the bolus and lower pressure in front of the bolus-That pressure differences is what is pushing it down the esophagus.

Esophageal Phase

• UES/CP (cricopharynxgeus)/PES(Pharyngoesophageal) relaxes and opens to allow bolus to enter; the bolus is propelled down the esophagus via peristalsis

• LES relaxes to allow the bolus to enter the stomach