Structures preserved in functional neck dissection is -

"In contrast to a radical neck dissection, the internal jugular vein, the spinal accessory nerve, the cervical sensory nerves, and the sternocleidomastoid muscle are preserved unless they are adherent to or invaded by tumor"- Schwartz Classical Radical neck dissection  → It involves the removal of following structures Cervical lymphatics and lymph nodes Internal jugular vein Accessory nerve Submandibular gland Sternomastoid muscle The main disability that follows operation is the dropping of the shoulder due to paralysis of the Trapezius muscle as a consequence of excision of accessory nerve. Modified Radical Neck dissection (Functional neck dissection)  → In this operation all the lymphatics and lymph nodes are removed as in radical neck dissection. The difference is that one or more of the following structures are preserved. Accessory nerve Stemocleidomastoid muscle Internal jugular vein