Normal Swallow

Normal Swallow

1. Oral Prepartory Phase

   • Step 1: Food is brought into oral cavity. Lips teeth and cheeks grasp food. Lips create anterior oral seal
     • Perioral Muscles
       • Orbicularis oris
       • Buccinator
     • Jaw Depressor Muscles
       • Ant. Digastric
       • Mylohyoid
       • Lateral pterygoid
       • Geniohyoid
     • Facial (VII)
     • Trigeminal (V)
     • Spinal C1
   • Step 2: Bolus formation where jaw moves in rotary lateral pattern, tongue positions food on the occlusion side of teeth, buccal tone keeps food from falling into the lateral sulci, and saliva helps break down food.
     • Muscle of the cheeks
       • Buccinator
     • Muscles of the Tongue
       • Superior longitudinal
       • Inferior longitudinal
       • Transverse
       • Vertical
     • Muscles of Mastication
       • elevators
         • Temporalis
         • Masseter
         • medial pterygoid
       • depressors
         • Ant. digastric
         • Mylohyoid
         • Lateral pterygoid
         • Geniohyoid
     • Facial (VII)
     • Hypoglossal (XII)
     • Trigeminal (V)
     • Spinal (C1)
   • Step 3: Bolus is contained between the tongue and the palate. The Tongue tip contacts the alveolar ridge to keep bolus in front. The lateral sides of the tongue are up against the teeth to hold bolus. The back of the tongue contacts the soft palate to hold bolus and form the retro-oral seal.
     • Muscles of the tongue
       • Genioglossus
       • Styloglossus
       • palatalglossus
     • Muscles of the soft palate
       • Palatopharyngeus
     • Hypoglossal (XII)
     • Vagus (X) and Accessory (XI)

2. Oral Transport Phase

   • Step 1: Tongue uses a "stripping wave" action to move bolus to the back of the tongue.
     • Muscles of the tongue
       • Intrinsic muscles
       • Genioglossus
     • Hypoglossal (XII)
   • 1 sec or less
   • Step 2: Bolus is loaded on to the back of the tongue. The soft palate elevates and the posterior of the tongue lowers, breaking the retro-oral seal. The tongue dorsum moves down and forward to load bolus.
     • Muscles of the Tongue
       • Genioglossus
       • Hyoglossus
     • Palate elevators
       • Levator veli palatini
       • Tensor veli palatini
       • Musculus Uvulae
     • Hypoglossal (XII)
     • Vagus (X) and Accessory (XI)
     • Trigeminal
   • Step 3: Sensory receptors in the anterior faucial pillars, tongue base, and posterior wall are stimulated by the bolus, triggering the pharyngeal phase of the swallow.
     • Muscles of the tongue
     • Hypoglossal (XI)
     • Oropharynx
     • Vagus (X)
     • Glossopharyngeal (IX)

3. Pharyngeal Phase

   • Step 1: Soft palate elevates to contact the posterior pharyngeal wall, forming the velopharyngeal seal and preventing the bolus from escaping into the nasopharynx
     • Soft palate eelavators
       • Levator veli palatini
       • musculus uvulae
       • Tensor veli palatini
     • Vagus (X) and Accessory (XI)
     • Trigeminal
   • Step 2: The tongue base propels bolus into the pharynx with a piston like motion while the mandible is kept stabilized.
     • Muscles of the tongue
     • Muscles of mastication
     • Hypoglossus (XII)
     • Trigeminal
   • Step 3: Laryngeal closure
     • Glottal clossure
       • Muscles of cord adduction
         • Lateral cricoarytnoid
         • Interarytenoids
         • Cricothyroid
     • Vestibule closure
     • Arytenoid cartilages move to touch base with epiglottis
       • muscles to move arytnoids to epiglottic base
         • Thyroarytenoid
         • Supraglottic Muscles
     • Epiglottis deflects to a horizontal position (due to hyolaryngeal elevation, muscular forces, and downward pressure of the bolus!)
       • Muscles of the Larynx
         • elevation
           • Ant./Post. Digastric
           • Geniohyoid
           • Mylohyoid
           • Stylohyoid
           • Spinal (C1)
           • Facial (VII)
     • RLN of X
     • Trigeminal (V)
     • SNL of X
   • Step 4: (HLAE) They hyoid elevates pulling the larynx with it. Once the hyoid reaches max elevation, the thyroid cartilage continues to be in motion, pulling the larynx up with it.
     • Suprahyoid muscles
       • Ant. Digastric
       • Stylohyoid
       • Post. Digastric
       • geniohyoid
       • myohyoid
     • Spinal (C1)
     • Trigeminal (V)
     • Facial (VII)
   • Step 5: The epiglottis deflects into the horizontal position to allow the bolus to empty out of the valleculae and move laterally toward the pyriform sinuses, away from the laryngeal vestibule.
     • Movement due to forces of laryngeal elevation
       • median hyoepiglottic ligament
       • Pre-epiglottic adipose tissue
     • Muscles of the epiglottis
       • aryepiglotticus
       • thyroepiglotticus
     • Movement due to forces of hyoid elevation
       • Lateral hyoepiglottic ligaments
   • Step 6: Opening of the Upper Esophageal Sphincter (UES)
     • (a) Muscle relaxes
       • Muscles of the UES opening
         • Cricopharyngeus
     • (b) Muscle becomes easy to work open
     • (c) UES is kept open by upward movement of the hyolaryngeal complex
       • Muscles elevating hyoid
         • Suprahyoid muscles
     • (d) Bolus helps pushes itself through UES with its own pressure (intrabolus pressure!)
   • Step 7: Bolus is cleared from pharynx
     • (a) Peristalisis (due to contraction of pharyngeal constrictors) move bolus down pharynx
       • Pharyngeal constrictor muscles
         • Superior, Middle, and Inferior pharyngeal constrictors
           • Vagus (X) and Accessory (XI)
     • (b) The pharynx shortens making it easier for bolus to move out of it.
       • Muscles shortening the pharynx
         • Stylopharyngeus
           • Glossopharyngeal (IX)
         • Salpingopharyngeus
           • Vagus (X) and Accessory (XI)

4. Esophageal Phase

   • Bolus is transported from pharynx to stomach
     • Primary Peristalisis: bolus arrives at UES and a persitalic wave moves the bolus to stomach
       • Secondary Peristalisis: Triggered by feeling of left over food in esophagus aka Intraesophageal distention!
       • Muscles of peristalisis
         • outer logngitudinal muscles
         • inner circular muscles
         • Vagus (X) - directed by nucleus ambiguus