Osseous anatomy of the posterior skull base. The sphenoid, temporal, and occipital bones form the posterior skull base. The squamosal and petrosal parts of the temporal bone articulate anteriorly with the greater wing of the sphenoid to form the floor of the middle cranial fossa. The petrous part articulates medially with the clival part of the occipital bone to form the petroclival fissure. The mastoid part of the temporal bone articulates with the squamosal part of the occipital bone to form the occipitomastoid suture. The petrous part of the temporal and the condylar or lateral part of the occipital bone form the anterior and posterior margins of the jugular foramen, respectively. The jugular tubercle and hypoglossal canal are also located in the condylar or lateral part of the occipital bone. (Image courtesy of JC Fernandez-Miranda)