This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Head and neck, Subject name: Anatomy
Structures preserved in in functional neck dissection 
Select and explain. 
A. Carotid aery , Vagus nerve, B. Sternocleidomastoid muscle , Internal jugular vein, C. Neck nodes, D. Spinal accessory nerve , Submandibular salivary gland
B: Sternocleidomastoid muscle , Internal jugular vein
Answer: B: Sternocleidomastoid muscle , Internal jugular vein 
Explanation: "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"- Schwaz 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 Ref : Love & Bailey 25/e p733