This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Dental
Which of the following is not a structural element of TMJ? 
Select and explain. 
A. Sigmoid notch, B. Articular disc, C. Capsular ligament, D. Joint cavities
A: Sigmoid notch
Answer: A: Sigmoid notch 
Explanation: Sigmoid notch (or) mandibular notch forms the sharp upper border of the ramus the condyle and coronoid process.