Transoral view of skeletal anatomy. This open mouth perspective provides a broad view of the features of the skull. The opening is bounded inferiorly by the mandible whose condyle or head articulates with the mandibular fossa of the temporal bone. The opening is bounded superiorly by the maxillae, which form the central part of the face. The medial borders of these bones form the principal boundary of the piriform aperture to the nasal cavity. In this view, the perpendicular plate of the ethmoid bone and vomer form the osseous portion of the nasal septum. Below the inferior orbital rims are the infraorbital foramina for transmission of the infraorbital neurovasculature. Through the oral opening, superiorly, is the hard palate formed by the palatine processes of the maxillary bones and the horizontal plates of the palatine bones. Near their union posteriorly are the greater and lesser palatine foramina for transmission of greater and lesser neurovasculature to the hard and soft palate, respectively. The clivus (not labeled) lies anterior to the foramen magnum, a large foramen within the occipital bone. It joins the temporal bone at the petroclival fissure, which leads to the jugular foramen, a space between portions of the petrous temporal bone and occipital bone. The inferior petrosal sinus occupies this fissure and drains into the internal jugular vein through the jugular foramen. Anterior to this opening is the carotid canal for the internal carotid artery. Between the jugular foramen and the foramen magnum is the hypoglossal canal for the hypoglossal nerve. The occipital bone articulates with the atlas, which in turn articulates with the axis. The dens or odontoid process can be seen extending from the body of the axis behind the anterior arch of the atlas. Posterior to the mandibular condyle and fossa is the mastoid process and superior to the mandibular fossa is the zygomatic arch. (Image courtesy of AL Rhoton, Jr.)