Carotid sheath sternum. The four major structures contained in the carotid sheath are: The carotid artery lies medial to the internal jugular vein, and the vagus nerve is situated posteriorly between the two vessels. In the upper part, the carotid sheath also contains the glossopharyngeal nerve (IX), the accessory nerve (XI), and the hypoglossal nerve (XII), which pierce the fascia of the carotid sheath. The ansa cervicalis is embedded in the anterior wall of sheath. It is formed by "descendens hypoglossi" (C1) and "descendens cervicalis" (C2-C3). The three major fascial layers in the neck contribute to the carotid sheath: the investing fascia,
Striate arteries Striate arteries Striate arteries or ganglionic arteries arise from the middle cerebral artery and supply deep structures in the cerebrum, including the internal capsule and reticular formation. Strokes in these vessels are common and can cause extensive damage. This is because emboli are carried up the carotid and tend to be swept into the MCA, sometimes called the "artery of stroke", and are prone to getting stuck at this branch point in the lateral sulcus. The middle cerebral artery (MCA) is a large-diameter vessel that branches at an acute angle from the internal carotid artery. The MCA passes laterally just