10.31.11+-+Pharynx

Pharynx


 * 1. Define the components of the alimentary layer of the cervical viscera.**

This is the throat portion of the neck. It is composed of the pharynx, larynx, and esophagus.


 * 2. Define the boundaries of the pharynx and those of its three components (nasopharynx, oropharynx and laryngopharynx)**

The superior boundary of the nasopharynx and pharynx is the roof of the posterior extension of the nasal canal formed by the body of the sphenoid and the basilar part of the occipital bone. The nasopharynx and the oropharynx are separated by the soft palate. The oropharynx is posterior to the oral cavity. The oropharynx and laryngopharynx are separated by the superior border of the epiglottis. The inferior boundary of the laryngopharynx and the pharynx is formed by the inferior border of the cricoid cartilage anteriorly and the inferior border of the C6 vertebra posteriorly.

The anterior wall is incomplete, having communications with the nasal, oral, and larynx. The posterior wall is formed by the pharyngeal constrictors and fascia.


 * 3. Describe the landmarks (openings and regions) of the interior of the pharynx.**

Internally, the soft palate, uvula, and palatopharyngeal and palatoglossal arches divide the oral cavity from the oropharynx. The pharyngotympanic tube opens into the nasopharynx. The palatine tonsils are visible between the palatopharyngeal and palatoglossal arches. The epiglottis is a cartilaginous flap elevated anteriorly to close off the larynx and trachea.


 * 4. Review the bones of the base of the skull and cervical spine that anchor the soft structures.**

Pharyngeal tubercle: bump on median inferior surface of basilar part of occipital bone Hard palate: anterior 2/3 formed by maxillary bone, posterior 1/3 formed by palatine bone Styloid process: lateral medioinferior facing projection of temporal bone. Site of attachment for 5 structures. Pterygoid hamulus: a lateral curve of the inferior border of the medial pterygoid plate of the lesser wing of the sphenoid bone. Mylohyoid line of mandible: a ridge extending superiorly and posteriorly from the symphysis of the mandible along the body. C1 - Atlas C2 - Axis

(Mad Men Memory device: Sal has a sensitive Palate and refined sense of Style)
 * 5. Describe the origins, insertions, actions and innervations of the three internal (longitudinal) layers of pharyngeal muscles.**
 * **Muscle** || **Origin** || **Insertion** || **Innervation** || **Main Action** ||
 * **Palatopharyngeus** || Hard palate and palatine aponeurosis || Posterior border of lamina of thyroid cartilage and side of pharynx and esophagus || Pharyngeal branch of vagus and pharyngeal plexus || Elevate (shorten and widen) pharynx and larynx during swallowing and speaking ||
 * **Salpingopharyngeus** || Cartilaginous part of pharyngotympanic tube || Blends with palatopharyngeus || Pharyngeal branch of vagus and pharyngeal plexus || Elevate (shorten and widen) pharynx and larynx during swallowing and speaking ||
 * **Stylopharyngeus** || Styloid process of temporal bone || Posterior and superior borders of thyroid cartilage with palatopharyngeus || Glossopharyngeal Nerve || Elevate (shorten and widen) pharynx and larynx during swallowing and speaking ||


 * 6. Describe the origins, insertions, actions and innervations of the external circular layer of pharyngeal muscles.**

These constrictors are all wrapped deeply and superficially by two distinct layers of fascia. Internally they are layered by the pharyngobasilar fascia (thick). Externally they are layered by buccopharyngeal fascia (thin). The pharyngobasilar fascia thickens superiorly to fill openings between cranium and superior constrictor muscles.
 * Muscle || Origin || Insertion || Innervation || Action ||
 * Superior pharyngeal constrictor || Pterygoid hamulus, pterygomandibular raphe, posterior end of mylohoid line of mandible, and side of tongue || Pharyngeal tubercle on basilar part of occipital bone || Pharyngeal branch of vagus and pharyngeal plexus || Constrict walls of pharynx during swallowing ||
 * Middle pharyngeal constrictor || stylohyoid ligament and greater and lesser horns of hyoid || Pharyngeal raphe || Pharyngeal branch of vagus and pharyngeal plexus, plus branches of external and recurrent laryngeal nerves of vagus || Constrict walls of pharynx during swallowing ||
 * Inferior pharyngeal constrictor || Oblique line of thyroid cartilage and side of cricoid cartilage || Cricopharyngeal part encircles pharyngoesophageal junction without forming a raphe || Pharyngeal branch of vagus and pharyngeal plexus, plus branches of external and recurrent laryngeal nerves of vagus || Constrict walls of pharynx during swallowing ||


 * 7. Describe the artery, veins, and lymphatic vessels (including tonsillar ring) supplying this region.**

Arteries: According to his slides, seven arterial branches subserve the pharynx (SALT API). They are underlined.


 * 1) Brachiocephalic Trunk
 * 2) Common Carotid
 * 3) External Carotid
 * 4) __Superior Thyroid__
 * 5) __Ascending pharyngeal__
 * 6) __Lingual__
 * 7) Facial
 * 8) __Tonsillar__
 * 9) __Ascending palatine__
 * 10) Maxillary
 * 11) __Pharyngeal branch__
 * 12) Subclavian
 * 13) Thyrocervical trunk
 * 14) __Inferior thyroid__

The two tonsils to remember are the palatine tonsils (jugulodigastric nodes) and the pharyngeal tonsils (adenoids). There are also the lingual tonsils and tubal tonsils that dontiubte to pharyngeal tonsillar ring.

This is a listing of structures that divide the external muscles of the pharynx in order of superior --> inferior:


 * 1) Cranium
 * 2) Levator veli palatini
 * 3) Pharyngotympanic tube
 * 4) Ascending palatine artery
 * 5) Superior pharyngeal constrictor
 * 6) Stylopharyngeus
 * 7) Glossopharyngeal nerve (runs on belly of stylopharyngeus, its one muscle it innervates)
 * 8) Stylohyoid ligament
 * 9) Middle pharyngeal constrictor
 * 10) Internal laryngeal nerve (pharynx branchial muscular innervation superior to laryngal folds)
 * 11) Superior laryngeal artery
 * 12) Superior laryngeal vein
 * 13) Inferior pharyngeal constrictor
 * 14) Recurrent laryngeal nerve (pharynx branchial muscular innervation inferior to laryngal folds)
 * 15) Inferior laryngeal artery


 * 8. Describe the nervous innervations of the pharynx and cervical esophagus and voluntary and involuntary nature of each of the three stages in coordination movement of the bolus during deglutition.**

The first step is voluntary. The food is pushed up against the palate and then pushed into the oropharynx by the tongue and soft palate (CN - XII and X). That is quickly followed by an involuntary elevation of the soft palate that seals the nasopharynx (CN X). Simultaneously, the pharynx widens and shortens via action of suprahyoid (C1, CN - V and VII, and N. to mylohyoid) and longitudinal pharyngeal muscles (CN X). This action allows passage of the bolus while simultaneously closing the tracheal opening with the epiglottis. Finally, the three constrictor muscles contract sequentially in a superior to inferior direction (CN X) propelling the bolus toward the esophagus.


 * 9. Describe the most common clinical problems arising in this region.**


 * 1) Consequences of discoordination of deglutition
 * 2) Aspiration of food or fluid (bolus pushed into oropharynx without elevation of the soft palate)
 * 3) Swallowing of air (deglutition of bolus of air)
 * 4) Regurgitation through nose
 * 5) Consequences of pathology of palatal arches
 * 6) If they are particularly flaccid, they can oscillate with air movement causing snoring and obstructive apnea. One solution is uvulopalatopharynoplasty (removal of excess tissue in throat).