E, The superior and inferior oblique have been exposed by reflecting the more superficial muscles. The C1 transverse process and rectus capitis lateralis rest against the posterior surface of the internal jugular vein. The rectus capitis lateralis attaches to the jugular process of the occipital bone at the posterior margin of the jugular foramen. Retracting the levator scapulae exposes the segment of the vertebral artery ascending through the C2 transverse foramen in front of the ventral ramus of the C2 nerve root. The vertebral artery, as it passes medially along the upper surface of the posterior arch of the atlas, is situated in the floor of the suboccipital triangle located between the superior and inferior oblique and rectus capitis posterior major. F, The internal carotid artery has been displaced posteriorly to expose the branches of the ascending pharyngeal, which pass through the foramen lacerum, jugular foramen, and hypoglossal canal to supply the surrounding dura. The chorda tympani exits the skull in the medial part of the condylar fossa by first passing through the petrotympanic and then along the squamotympanic sutures. G, The tympanic bone forming the lower and anterior margin of the external meatus has been removed, but the tympanic sulcus to which the tympanic membrane attaches has been preserved. The surface of the temporal and occipital bones surrounding the jugular foramen and carotid canal have an irregular surface that serves as the attachment of the upper end of the carotid sheath. The mastoid segment of the facial nerve and the stylomastoid foramen are situated lateral to the jugular bulb. The chorda tympani arises from the mastoid segment of the facial nerve and courses along the deep side of the tympanic membrane crossing the neck of the malleus. It exits the skull by passing through the petrotympanic and squamotympanic sutures and joins the lingual branch of the mandibular nerve distally. The carotid ridge separates the carotid canal and jugular foramen. Meningeal branches of the ascending pharyngeal and occipital arteries enter the jugular foramen. The glossopharyngeal, vagus, and accessory nerves pass through the jugular foramen on the medial side of the jugular bulb. H, The tympanic ring and bone lateral to the tympanic cavity have been removed. The internal carotid artery has been displaced forward out of the carotid canal to expose the carotid sympathetic nerves that ascend with the artery. The glossopharyngeal, vagus, accessory, and hypoglossal nerves exit the skull on the medial side of the internal carotid artery and jugular vein. The glossopharyngeal and hypoglossal nerves pass forward along the lateral surface of the internal carotid artery, and the accessory nerve descends posteriorly across the lateral surface of the internal jugular vein. The vagus nerve descends in the carotid sheath. (Images courtesy of AL Rhoton, Jr.)