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%).
Relevant Anatomy. The spinal accessory nerve (SAN) is formed by 2 parts. The spinal or motor portion includes fibers that originate in the ventral horn of the upper 4 or more cervical segments of the spinal cord. The fibers may originate from as low as the fifth and rarely the seventh cervical segment.