Spinal pa of accessory nerve supplies: (A) Platysma, (B) Sternocleidomastoid, (C) Stylohyoid, (D) Diagastric
Answer is B. Sternocleidomastoid and trapezius are supplied by spinal accessory nerve. Both of them develop from brachial arch mesoderm.It is tested by turning the neck against resistance.B D Chaurasia 7th edition Page no: 65 ( refer head and neck volume )