Swallowing: Muscle Cont... & Normal Swallowing

Larynx: Extrinsic Muscles - Suprahyoids

Muscles from hyoid & above ELEVATES

Hyoid to mandible

- Anterior belly of digastrics

- Mylohyoid

- Geniohyoid

Hyoid to skull

- Posterior belly of digastrics

- Stylohyoid

Hyoid to tongue

- Hyoglossus

Larynx to skull

- Stylopharyngeus

- Palatopharyngeus

- Salpingopharyngeus

Larynx: Hyoid to mandible - CN?

Trigeminal Nerve - CN V

Larynx: Hyoid to skull

Facial Nerve - CN VII

Cervical Plexus

Spinal nerves (C1-C5)

Larynx: Extrinsic Muscles - Infrahyoids

Muscles from hyoid & below DEPRESSES

Cranial Plexus

- Thyrohyoid : C1

- Sternohyoid : C1 - C3

- Sternothyroid: C1 - C3

- Omohyoid: C1 - C3

Upper Esophageal Sphincter (UES)

Inferior pharyngeal constrictor

- Thyropharyngeus

- Cricopharyngeus

- Tonically contracted

- Relaxes during the swallow

Normal Swallow Events

Apnea onset --> Posterior lingual propulsion --> Swallow --> Velar elevation --> Laryngeal vestibule closure --> Pharyngeal constriction + elevation --> UES opening --> Apnea onset

Goals of Swallowing:

Bolus Efficiency: How safely and effectively the bolus moves into the esophagus

Airway Protection: Preventing material from entering the larynx and/or trachea

Oral Phase

Voluntary

Sequential process: Bolus Acceptance --> Mastication --> Bolus propulsion

Oral Cavity

Bolus containment + Preparation

Containment

- Lips: Closure after intake

- Cheeks: Adequate tension

Preparation

- Teeth: Mastication

- Tongue: Posterior bolus propulsion

- Cheeks: Bolus efficiency, midline

- Soft palate: Depresses for airway protection

Posterior lingual: Propulsion

- Quick pressure build

- Moves bolus into pharynx

- Epiglottic inversion

Pharyngeal Phase

Involuntary

Swallow trigger

- Velar elevation

- Laryngeal vestibule closure

- Pharyngeal constriction + elevation

- Upper esophageal opening

Oropharynx

Propulsion + Velopharyngeal

Propulsion

- Soft palate

- Lateral pharyngeal walls

- Base of tongue

Velopharyngeal

- Soft palate: Elevates as tongue propels

- Tongue: Elevates

Swallow trigger: Approximate zone of initiation

- Separates volitional from reflexive events

- Variability is normal

Young adults typically trigger a swallow SOONER than older adults

Velar Elevation

- Prevents nasal regurgitation

- Build downward pressure

- NOT involved in airway protection

Hypopharynx

Propulsion + Larynx

Propulsion

- Pharyngeal constrictors

- Pyriform sinuses

- Cricopharyngeal function

Larynx

- Closure: Glottis, ventricular folds, epiglottis

- Pharyngeal squeeze

- Hyoid elevation

Laryngeal vestibule closure

Hyolaryngeal excursion

- epiglottis moves higher - BOT

- UES stretching

Arytenoid adduction

- forward movement

Aryepiglottic fold bunching

- forward movement

Epiglottic inversion

- BOT + pharyngeal constriction

Pharyngeal constriction: Elevation

Sequential

1. superior PC

2. middle PC

3. inferior PC

Pharyngeal stripping wave

Laryngeal elevation, epiglottic inversion

Esophageal phase

Involuntary

Final Phase

- UES opening

- Peristalsis

- LES opening

Esophagus

Cricopharyngeus (CP) relaxes

Laryngeal elevation

Bolus passage

Sequential contraction of esophagus

Relaxation empties bolus into stomach

1. UES opening

2. Primary peristaltic wave

3. Secondary peristaltic wave

4. LES opening