Anatomy of the Pharynx and Palate

SPSC161

Pharynx

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* Shared space for breathing and eating
* From the posterior aspects of oral and nasal cavities to the esophagus
* Epiglottis
* Nasopharynx - top small red circle
* Oropharynx - middle small red circle
* Laryngopharynx - bottom small red circlr
* AKA hypopharynx
* The large encasing circle surrounds the whole of pharynx

Pharyngeal muscles

* Outer circular layer 
* Superior constrictor
* Middle constrictor
* Inferior constrictor
* Thyropharyngeus
* Cricopharyngeus

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* Constrict the pharynx and propel the bolus downwards

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* Inner longitudinal layer
* Stylopharyngeus
* Salpingopharyngeus
* Palatopharyngeus(commonly referred to as strap muscles, their job is to elevate the pharynx and also shorten the pharynx)
* Shorten and dilate/widen the pharynx

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Bolus refers to food or fluid which has been masticated in the oral cavity which has travelled down to either the larynx, pharynx or eosophagus 

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Pharyngeal constrictors

Superior and middle constrictor

Superior

* Originates in the Pterygomandibular raphe and inserts into the median pharyngeal raphe

Middle

* hyoid bone to median pharyngeal raphe
* Pulls posterior pharyngeal wall forward
* Narrows pharyngeal lumen during swallowing

Inferior constrictor

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* Strongest of the 3
* Two sections
* Thyropharyngeus
* Thyroid lamina to median pharyngeal raphe
* Lower/ depress the pharynx
* Similar action to upper and middle

Attachments pt. 1

Cricopharyngeus

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* Cricoid cartilage to median pharyngeal raphe
* Fibers more horizontal
* Cricopharyngeus muscle
* Upper esophageal sphincter - closes off the esophagus, closes tightly to stop stomach acid coming up the other way

### Upper esophageal sphincter (UES)

* Made up of cricopharyngeus muscle and cervical esophageal muscle
* Zone of high pressure that separates the pharynx from the esophagus (3-4 cms vertically)
* Sits tonically contracted at rest
* Stops air entering esophagus
* Stops stomach contents entering pharynx
* Innervated by vagus nerve and pharyngeal plexus
* Lots of negative pressur underneath the UES

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Salpingopharyngeus

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* Origin: Eustachian tube
* Insertion: lateral walls of the pharynx
* Elevates the pharynx during swallowing
* Innervated by pharyngeal plexus
* Little tubes located laterally to our velum, reason our ears pop on planes

Stylopharyngeus

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* Origin: Styloid process of temporal bone
* Insertion: pharyngeal constrictors
* Elevates and dilates the pharynx
* Innervated by CN IX, glossopharyngeal

Palatopharyngeus

* Alsoconsideredavelarmuscle
* Forms the posterior faucial pillar (palatopharyngeal arch) 
* Origin: aponeurosis of the soft palate
* Insertion: thyroid cartilage and inferior pharynx

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*  Two purposes:
* Elevates the pharynx and larynx
* Lowersthesoft palate
* Pharyngeal plexus

Inner longitudinal muscles

Tonsils

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* Palatine
* Between anterior faucial pillar (palatoglossal arch) and posterior faucial pillar (palatopharyngeal arch)
* Lingual
* Oropharynx
* Pharyngeal
* AKA adenoid
* Nasopharynx

### The palate and velum

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Hard palate

* Anterior 2/3rds of palate
* Palatine process of the maxilla

Soft palate/velum

* Posterior 1/3rd of the palate
* Connective tissue, muscular fibers, mucosa

Uvula

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* Dangly portion of the soft palate
* When it contracts it helps elevates the soft palate

Velar muscles

Velar (soft palate) muscles

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Elevators

* Levator veli palatini: forms bulk of the soft palate
* Musculus uvulae: only intrinsic muscle of the soft palate

Depressors

* (Palatopharyngeus)
* Palatoglossus
* Tensor veli palatini (trigeminal)

All innervated by pharyngeal plexus EXCEPT tensor veli palatini

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Levator veli palatini - (elevate the palate)

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* Origin: temporal bone and near the eustachian tube
* Insertion: aponeurosis of the soft palate/ velum
* Pulls soft palate towards the posterior pharyngeal wall
* Innervated by pharyngeal plexus (CN 9&10)

### Musculus uvulae

* AKA Uvula
* Muscle within the uvula
* Origin:aponeurosis of the soft palate
* Insertion:uvula
* Small role in elevation of the soft palate
* Innervated by pharyngeal plexus
* Goes along for a ride with the other muscles

Palatoglossus

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* Forms the anterior faucial pillar (glossopalatal arch)
* Origin:aponeurosisof the soft palate
* Insertion:lateral posterior tongue on which is fixed:
* Elevates the base of tongue
* Depresses the palate • Innervated by pharyngeal plexus
* Tensor veli palatini • Origin: sphenoid bone,
* Insertion: aponeurosis of soft palate • “tenses” the palate
* Innervated by CN V trigeminal
* Glossopalateal seal, stops the food from falling back in to our throat before we are ready to swallow

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Tensor veli Palatini

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* Origin: sphenoid bone, 
* Insertion: aponeurosis of soft palate
* “Tenses” the palate
* Innervated by CN V trigeminal