Dissection view of the inferior aspect of the skull on the right side. For orientation, the upper border of the image is anterior; the lower border is posterior. Note also the styloid process, and posterolateral to this, the stylomastoid foramen transmitting the facial nerve. Medial to these structures is the jugular foramen, transmitting the internal jugular vein and glossopharyngeal, vagus, and spinal accessory nerves. Just anteromedial to the jugular foramen is the opening of the carotid canal for the internal carotid artery. Removal of a portion of the occipital bone has exposed the sigmoid sinus and, similarly, removal of a portion of the occipital condyle has opened the hypoglossal canal to reveal the hypoglossal nerve and venous plexus. Medial to this is the vertebral artery ascending through the foramen magnum adjacent to the medulla oblongata (spinal dura has been removed). (Image courtesy of AL Rhoton, Jr.)