Identify the proximal segments of the cranial nerves emerging from the base of the skull.

1. (ON THE RIGHT SIDE ONLY) It may be necessary to remove the sternocleidomastoid muscle and/or external ear to complete sections B through F. Be careful and leave the auriculotemporal, facial and acessory nerves intact.
2. (ON THE RIGHT SIDE ONLY) Identify the stylohyoid, styloglossus and stylopharyngeus muscles attaching to the styloid process. (G 8.28;N 70;Gl 44.28) Return to the dangling facial nerve branch. Trace the facial nerve to the stylomastoid foramen. (G 7.47C;N 71;Gl 40.24) The stylomastoid foramen is typically in the same plane as the posterior border of the external auditory meatus.
3. (ON THE RIGHT SIDE ONLY) Return to the accessory nerve. Trace the accessory nerve in the superior direction until it approaches the jugular foramen. (G 7.47C;N 32;Gl 44.30)
4. (ON THE RIGHT SIDE ONLY) Return to the hypoglossal nerve. Trace the hypoglossal nerve (superficial to the internal and external carotid arteries) in the superior direction until it appears to become a branch of the vagus nerve. (G 7.47C;N 71;Gl 44.30)
   Important Relationship

   • The hypoglossal nerve passes lateral to the internal and external carotid arteries, and medial to the internal jugular vein.
5. (ON THE RIGHT SIDE ONLY) Return to the superior laryngeal (internal laryngeal) nerve. Trace the superior laryngeal nerve (deep to the external and internal carotid arteries) in the superior direction until it branches from the vagus nerve.
   Important Relationship

   • The superior laryngeal nerve passes medial to the internal and external carotid arteries.
6. (ON THE RIGHT SIDE ONLY) Attempt to identify and trace the glossopharyngeal nerve and pharyngeal branch (vagus) in the superior direction until they approach the vagus nerve and the jugular foramen.
   Important Relationship

   • The glossopharyngeal nerve (and pharyngeal branch of the vagus nerve) passes between the internal and external carotid arteries.