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. Author manuscript; available in PMC: 2015 Aug 1.
Published in final edited form as: Oral Oncol. 2014 Jun 3;50(8):746–752. doi: 10.1016/j.oraloncology.2014.05.003

Table 1.

Description of OAR Contours

Structures Definition
Cerebellopontine Angle Brainstem visible between the superior most aspect of the facial canal to the superior most aspect of the jugular foramina
Medulla Brainstem visible between the superior most aspect of the jugular foramina to the foramen magnum to include brain stem nuclei of CN IX, X and XII
Ipsilateral and Contralateral Jugular Foramina Entire jugular foramina contoured in bone window to include CN tracts of IX and X
Ipsilateral and Contralateral Cranial Nerve Tracts Carotid artery and jugular vein from the exit of the jugular foramen posterior to the styloid process to include the nerve tracts of CN IX, X, XII
Suprahyoid musculature Combination of musculature (including mylohyoid, geniohyoid) superior and anterior to the hyoid up to the floor of mouth
Base of Tongue Tongue posterior to the retromolar trigone if teeth were visible or the portion of the tongue up until 1 cm anterior to the angle of the mandible if patient was edentulous
Superior Pharyngeal Constrictor Constrictor muscles extending superiorly to the skull base and inferiorly to the most superior surface of the hyoid including the insertions onto the mylohyoid line
Middle Pharyngeal Constrictor Constrictor muscles extending through the levels of the hyoid (from superior to inferior edge of hyoid)
Inferior Pharyngeal Constrictor Constrictor muscles extending superiorly to the most inferior surface of the hyoid and cricoid cartilage
Parotid Glands Parotid glands contoured in the head and neck window
Superior Larynx (i.e., glottic and supraglottic) Larynx from its most superior extent inferiorly to the level of and including the glottis
Inferior Larynx (i.e., subglottic) Larynx inferior to the glottis
Hard Palate Hard palate contoured in bone window
Soft Palate Soft palate contoured in soft tissue window including the uvula
Retropharyngeal space Potential nodal space posterolateral to the pharyngeal constrictors superiorly to the skull base and inferiorly to the level of the hyoid
Intrinsic Tongue Musculature of the tongue excluding the suprahyoid musculature
Anterior and Posterior Oral Cavity Mucosal surfaces of the oral cavity including the buccal mucosa, the lips, the floor of mouth and the tongue divided equally in the sagittal plane