Deep injury of neck always involves: (A) Platysma, (B) Trapezius, (C) Sternocleidomastoid, (D) Longus colli
Answer is A. Investing layer lies deep to the platysma and surrounds the neck like a collar. The surgeon has to stitch platysma muscle separately so that skin does not adhere to deeper neck muscles otherwise the skin will get an ugly scar. Ref BDC volume 3;sixth edition pg 81