The anterior part of the skull and the visceral structures in the neck must now be separated from the vertebral column and the prevertebral muscles. Use great care in making this separation in the region posterior to the jugular foramen, as the structures in the carotid sheath may be damaged. The muscles between the base of the skull and the upper cervical vertebrae will be destroyed by this procedure but the pharynx will remain undamaged if reasonable care is taken. The separation is accomplished by pulling, prying and cutting as necessary. If these muscles are not removed, it will be impossible to see the upper portion of the superior constrictor and its attachments to the skull.
Retropharyngeal Structures Identify and clean the posterior aspect of the internal jugular vein .
Then find the spinal accessory nerve , where it was previously identified entering the sternocleidomastoid , and trace it back to the jugular foramen, noting how it is related to the internal jugular vein. It may pass either anterior or posterior to the vein. Again, identify the superior cervical ganglion and the cervical sympathetic trunk . Look for the superior laryngeal nerve , which is the branch off the inferior ganglion passing medial to the internal carotid artery to enter the gap between the middle and inferior constrictor muscles of the pharynx. The large nerve which appears to branch from the lateral side of the inferior ganglion of the vagus is the hypoglossal nerve , which passes lateral to the internal carotid.