Antrochoanal polyps arise from the maxillary sinuses and are the much less common; ethmoidal polyps arise from the ethmoidal sinuses. Symptoms of polyps include nasal congestion, sinusitis, anosmia (loss of smell), and secondary infection leading to headache.
Relationship of internal jugular vein to the spinal accessory nerve (SAN). Spinal accessory nerve (SAN) posterior to the internal jugular vein. As the nerve approaches the sternocleidomastoid muscle (SCM), it may perforate the cleidomastoid portion of the SCM (80%) or run posterior to it (20%).
Key Points. 1  Cranial nerve XI is responsible for tilting and rotating the head, elevating the shoulders, and adducting the scapula. 2  Most of the fibers of the accessory nerve originate in neurons situated in the upper spinal cord. 3  Due to its unusual course, the accessory nerve is the only nerve that enters and exits the skull.