Read these threads at this Web address:
Power of imagination - meditationtime | Google Groups
After the throat chakra which covers the thorac region, the next major chakra is the 3rd eye and then there is the crown chakras, but they are other chakras in the head and also they are other mystic organs in the head of the subtle body.
Check my Meditation Pictorial book and you will get more information and clarification about this.