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%).
Sternocleidomastoid Muscle. Anatomy and supply. The sternocleidomastoid muscle is a two-headed neck muscle. It is innervated by the accessory nerve (cranial nerve XI) and direct branches of the cervical plexus (C1-C2). The sternal head originates from the manubrium sterni, the clavicular head from the middle part of the clavicle.