7 ⇓- 9 Long-term adverse effects from radiation or chemotherapy and high morbidity from traditional surgery through external mandibulotomy can reduce the quality of life, particularly in young patients who have to live with the consequences for far longer. The treatment protocol for HPV-positive SCC has shifted toward a “deintensification” approach to maintain favorable oncologic outcomes while minimizing treatment-related morbidity. 3 ⇓- 5 Surgery, radiation, and chemotherapy are the main treatment methods for oropharyngeal SCC and can be used alone or in combination depending on the cancer stage. 1, 2 HPV-positive oropharyngeal SCC is known for its excellent prognosis with substantially improved survival compared with HPV-negative SCC. Oropharyngeal squamous cell carcinoma (SCC) is a head and neck cancer with increasing prevalence as a consequence of rising human papillomavirus (HPV) infections. A focal weakness or deficiency in this area of the pharyngeal wall is termed a Killian dehiscence and can produce a pulsion-pseudodiverticulum, known as a pharyngeal diverticulum or pouch (Zenker diverticulum).ABBREVIATIONS: AUC area under the curve cN clinical node cT clinical tumor HPV human papillomavirus pN pathologic node pT pathologic tumor ROC receiver operating characteristic SCC squamous cell carcinoma TORS transoral robotic surgery The area of the pharyngeal wall at the junction between the thyropharyngeus and the cricopharyngeus is a potentially weak area. The middle and superior constrictors are enclosed by the thyropharyngeus fibers that wrap around to the midline raphe.The recurrent laryngeal nerve and inferior laryngeal vessels pass upwards deep to the lower border of the cricopharyngeus.It is always closed except for momentary relaxation during swallowing. Its closure prevents air from being sucked into the upper esophagus when intrathoracic pressure falls, allowing air to be sucked only into the permanently open trachea. It is physiologically in a tonic state, constricting the distal end of the pharynx (in coordination with the superior pharyngeal constrictor and the middle pharyngeal constrictor muscles). The cricopharyngeus has an important sphincteric function. It acts as a sphincter at the lower end of the pharynx and is always closed except for momentary relaxation during swallowing. Its muscle fibers are continuous with the circular muscular coat of the esophagus. Its fibers run continuously from one side of the cricoid arch to the other side around the pharynx without inserting into a midline raphe posteriorly. The cricopharyngeus muscle is rounder and thicker than the other constrictor muscles.

The lower fibers are horizontal and lie edge to edge with those of the cricopharyngeus component.

Its fibers curve around posteriorly and insert into the midline raphe. The thyropharyngeus muscle arises from the (a) thyroid cartilage at the oblique line and (b) the tendinous arch that spans the cricothyroid muscle. The inferior pharyngeal constrictor muscle is one of the pharyngeal constrictor muscles. The muscle is described as having two main parts, thyropharyngeus and cricopharyngeus, which originate from the oblique line of the thyroid lamina and lateral aspect of the cricoid cartilage respectively.

Pharyngeal constrictor muscles origin