oral cavity and pharynx

ORAL CAVITY

-part of the oral region
-where the food is ingested
-the voluntary action of swallowing is initiated in oral cavity.
-divided into :

i) oral vestibule : slit-like space between teeth and buccal gingivae and lips and cheek (the area
in front of the teeth)
ii)oral cavity proper : space between upper and lower dental arches (the area behind the teeth up to oropharynx )

PHARYNX

-posterior to nasal and oral cavities
-from cranial base --> inferior border of cricoid cartilage (anteriorly), inferior border of C6
(posteriorly)
-widest ( opposite hyoid)
-narrowest (inferior border of pharynx where it is continuous with esophagus)
-interior of pharnx

i) nasopharynx - choanae --> soft palate (pharyngeal tonsil)
ii)oropharynx- soft palate ---> superior border of epiglottis (palatine tonsil + lingual tonsil)
iii)laryngopharynx - superior border of epiglottis ---> inferior border of cricoid cartilage (C4-C6 posteriorly)

pharyngeal muscles

1) external layers-superior constrictor
-middle constrictor
-inferior constrictor
-function: constrict walls of pharynx during swallowing
2) internal layers-palatopharyngeus
-slapingopharyngeus
-stylopharyngeus
-function: elevate pharynx and larynx during swallowing and speaking

Nerves

-all innervated by pharyngeal branch of vagus nerve and pharyngeal plexus eXCEPT
stylopharyngeus (CNIX) and tensor veli palatini (CNV3)
-inferior constrictor is also innervated by external and recurrent laryngeal nerve of vagus

Artery
-tonsillar artery (branch of facial artery)

Vein
-external palatine vein (paratonsil vein) --> enters pharyngeal venous plexus