Soft Tissue

The tonsillar region is important as this can be a major site for squamous cell cancer including those caused by the human papilloma virus (HPV) subtype 16. The tonsillar pillar is formed anteriorly by the palatoglossus muscle and posteriorly by the palatopharyngeal muscle, with a glossopalatini sulcus inferiorly, this creates a triangulated region that encompasses the tonsillar lymphoid tissues. Above the oropharynx is the nasopharynx separated at the level of the soft palate. 

Nerves that innervate the oropharynx include the trigeminal nerve or CN V,  and the glossopharyngeal nerve or CN IX that innervates the oropharynx, tonsils and posterior 1/3 of the tongue. Pain from CN XI can travel along a branch called Jacobsen’s nerve, that also gives sensation to the inner portion of the tympanic membrane, middle ear mucosa, eustachian tube and mastoid. 

The walls of the oropharynx are formed by fascia and muscles, that includes laterally the tonsillar fossa, superficial mucosa, pharyngobasilar  fascia, superior constrictor  muscle and buccopharyngeal fascia and parapharyngeal space, with the palatoglossus muscle, palatopharyngeus muscle and stylopharyngeus muscles. Located deep to the parapharyngeal space is the carotid space. The posterior margin is made up of mucosa, the pharyngobasilar fascia, superior and middle constrictor muscles, buccopharyngeal fascia, retropharyngeal space, alar fascia, the potential danger space, prevertebral fascia and muscles.