What are the three negative lines?

Pubic tubercle, superior margin of pubic symphysis, posterior margin of pubic symphysis.

1, pubic tubercle: The pubic tubercle is located under the small abdomen of human body and above the pubic symphysis. You can touch the pubic tubercle of human body with your hands.

2, the upper edge of the pubic symphysis: The upper edge of the pubic symphysis is located on the left and right sides of the pubic bone of the human body, and you can feel obvious tenderness by touching it with your hands.

3. Posterior edge of pubic symphysis: The three needles of pubic symphysis have the edge of posterior edge of pubic symphysis on the left and right sides of human pubis, and you can feel obvious tenderness by touching them with your hands.