Pharynx – description, divisions, muscles, syntopy, vascular supply, innervation

The pharynx is the transitional space between the oral cavity and the respiratory and digestive systems. The pharynx is lined by stratified, non-keratinised squamous epithelium. It is divided into three sections: nasophaynx, oropharynx and laryngopharynx.

Nasopharynx

 * Base to C2
 * Respiratory function
 * Superior to the soft palate; posterior expansion of the nasal cavity

Oropharynx

 * C2 to C4
 * Digestive function
 * Superior to the soft palate; inferior to the tongue
 * Lateral to it are the palatoglossal and palatopharyngeal arches

Laryngopharynx

 * C4 to C6
 * Superior border is epiglottis
 * Inferior border is cricoid cartilage

Arteries

 * Ascending pharyngeal artery, external carotid artery medial group
 * Ascending palatine artery, from facial artery of external carotid artery
 * Tonsillar artery ,
 * Maxillary artery
 * Lingual artery

Veins

 * Pterygoid venous plexus
 * Facial vein
 * Internal Jugular Vein

Innervation

 * Motor and most sensory innervation is done by glossopharyngeal nerve

Muscular Innervation
 * Stylopharyngeus - glossopharyngeal nerve
 * All other muscles of the pharynx - pharyngeal plexus

Sensory
 * Nasopharynx - pharyngeal branch of the maxillary nerve
 * Oropharynx - glossopharyngeal nerve
 * Laryngopharynx - vagus nerve

Swallowing Reflex

 * It is the voluntary initiation of swallowing
 * 1) Reflex closure of the airway
 * 2) Reflex transport of food bolus down the oesophagus; through the pharynx