Delivery, vertex means: Vertex Delivery: The baby’s top is delivered via vertex.
Head comes first. Here, the vertex refers to top of head. This word
Latin for “vertex”, “whirlpool”, “whirlwind”, top of the mountain or
The top of your head. The hairs at the top are called the “top of your head”.
The head can form a whorl or whirllike shape.
(in Medical Dictionary)