The sternomastoid is innervated by which cranial nerve and is associated with which lymph node?

The sternocleidomastoid muscle, commonly referred to as the sternomastoid, is innervated by the accessory nerve, which is cranial nerve XI. This cranial nerve is responsible for motor function to the sternocleidomastoid and the trapezius muscles, facilitating movements such as head rotation and shoulder elevation.

The superficial cervical lymph nodes are associated with the sternocleidomastoid due to their location in relation to the muscle. These lymph nodes are positioned along the cervical fascia and receive lymphatic drainage from areas such as the scalp, face, and neck, which are in close proximity to the sternocleidomastoid. The positioning of these lymph nodes underlines their functional significance in the immune response and the drainage of lymph from relevant structures in the head and neck region.

In contrast, the other lymph nodes mentioned do not have a direct association with the sternocleidomastoid muscle or its innervation pathway.