SALC07 Biological Sciences Head & Neck 4: The Typical Adult Swallow Flora Wisdom MCRSLT/HPC

Review of oral & pharyngeal anatomy Cavities of the oropharynx:  Oral  Nasal  Oropharynx, naso- and laryngopharynx  Pharynx

The oral cavity Extends from oral opening (lips) to pillars of fauces at back Teeth and alveolar ridge or maxillae make up lateral margins

Soft palate Uvula Velum Pillars of fauces Anterior Posterior Also known as glossopharyngeal arch

Muscles of the velum MuscleFunction Levator veli palatineElevator *also movement of Eustachian tube Musculus uvulaeElevator/bunching Tensor veli palatineTenses and shortens PalatoglossusDepressor PalatopharyngeusDepressor

The pharynx Divided into areas: 1. Oropharynx 2. Nasopharynx 3. Laryngopharynx

Pharyngeal muscles  Superior pharyngeal constrictor  Middle pharyngeal constrictor  Inferior pharyngeal constrictors

Pharyngeal musculature MusclefunctionInnervation Superior pharyngeal constrictor Velopharyngeal closure Reduces diameter CN XI & X Middle pharyngeal constrictor Reduces diameterCN XI & X Inferior pharyngeal constrictor Reduces diameter: Two parts: CN XI & X 1.Cricopharyngeal muscle *arises from cricoid Muscular orifice of oesophagus 2. Thyropharyngeal muscle *arises from thyroid SalpingopharyngeusElevates lateral pharyngeal wallCN XI & X StylopharyngeusElevates pharynxCN IX

Intrinsic tongue muscles

The epiglottis  Leaf-shaped cartilage  Attached to root of tongue and hyoid

Pharyngeal spaces and places  Valleculae  Laryngeal vestibule  Pyriform sinuses  Upper Oesophageal Sphincter

Anatomical differences infants/adults

The infant pharynx  Pharynx generally curved from nasopharynx to hypopharynx  With growth the gentle curve gradually changes to become closer to 90’ angle seen in adults

Nasal breathing  Small oral cavity  Close proximity of tongue, soft palate and pharynx with the larynx appears to facilitate nasal breathing

The typical adult swallow

Swallowing  Eating and Drinking  Feeding  Swallowing Deglutition: “ a complex process involving neuromuscular control and coordination, sensory perception, integration of the autonomic and somatic nervous systems and respiratory function” (RCSLT 2006)

Label the following Nasal cavity Teeth Lips Pharynx Epiglottis Larynx Vocal Folds Soft Palate Tongue Trachea Oesophagus Lungs Stomach Pharynx

Swallowing Commonly divided into 4 stages: Pre-oral stage Oral stage (Oral preparation and oral transit) Pharyngeal stage Oesophageal stage

Pre-Oral  Anticipation  Hunger  Likes/Dislikes  Mood  Cognitive status  Physical status

Oral phase: 2 Parts; 1.Oral preparatory  To organise food/liquid in the mouth into a coherent bolus ready for swallowing 2. Oral/Oral Transit  To propel the bolus to the back of the mouth and trigger the pharyngeal stage of swallowing

Oral Preparatory  Begins when food/liquid enters mouth at level of lips  Nasal airway dependent-oral closure required  Voluntary control  Time-dependent on range of factors  Ends when bolus is formed and held ready for transit

Oral Stage: Prep

Oral Prep continued  Lips & jaw close, increased buccal tone  Range of complex and integrated tongue movements to form bolus  Liquid bolus cupped  Solid bolus-’tippers’ & ‘dippers’  Larynx & pharynx at rest, airway open  Chewing; as required. Food mixed with saliva  If not chewing, velum pulled anteriorally to rest on base of tongue-prevents spillage into pharynx & allows for variation in intra-oral pressure

Chewing skills  Requires lateral, rotary and grinding movements of tongue and jaw  Lateral and rotary tongue>jaw  Intermittent lip closure-Complete lip seal  Grinding movements

Oral Stage: Transit  Intact labial seal  Anterior to posterior tongue movement, begins ‘stripping’ action  Soft palate elevates and closes nasal airway

Oral stage: Transit

Pharyngeal stage

Pharyngeal Stage Oral Preparatory Phase Esophageal PhaseEsophageal Phase (8-20 sec) transit times can be measured from the point where the bolus enters the esophagus at the crico-esophageal juncture until it passes into the stomach at the gastro-esophageal juncture.crico-esophageal juncture

Oesophageal Stage  Cricopharyngeal sphincter relaxes and is pulled open  Bolus passes into oesophagus  CP sphincter closes  Structures return to resting position  Lower eosophageal sphincter relaxes

Oesophageal stage

Breathing and swallowing  Breath is held during the swallow  This is called APNOEA When something goes wrong:  Airway penetration  Aspiration  Silent Aspiration  Choking

Breathing and swallowing Cough response: – Needs intact sensory input from superior laryngeal nerve (X) and effective glottic closure – Voluntary cough may be present, but if no sensation in laryngeal vestibule, aspiration may still occur

The typical swallow, anatomy again. Why is it like that?

Variations in normal swallowing

Age Related Changes to the Swallow Any metabolic, biochemical and physiological processes change with increasing age. Notably:  Oral/pharyngeal motor function  Dentition  Hunger  Vision  Salivation  Taste

Neural Regulation of Swallowing

Neural control of swallowing Peri Medulla Nucleus tractus solitarius Nucleus ambiguous Cortex Peripheral afferent inputs (CN’s) Motor response (CN’s)

Cranial Nerves – CN V -- Trigeminal contains both sensory and motor fibers that innervate the face important in chewing – CN VII -- Facial contains both sensory and motor fibers important for sensation of oropharynx & taste to anterior 2/3 of tongue – CN IX -- Glossopharyngeal contains both sensory and motor fibers important for taste to posterior tongue, sensory and motor functions of the pharynx

Cranial Nerves  CN X -- Vagus  contains both sensory and motor fibers  important for taste to oropharynx, and sensation and motor function to larynx and laryngopharynx.  important for airway protection  CN XII -- Hypoglossal  contains motor fibers that primarily innervate the tongue

Is that all there is to it?