This post upload for all medizy members but in the my previous upload post in which describe about heart location in thoracic cavity but not clearly so one person named Shalini senthilnathan comment that show the pulmonory way from heart to lungs.In this image you can see that key chart in which 7th and 8th point for pulmonory artery and also very clearfully in x-ray.If u unavaible to see that chart then download this picture and zoom it then see carefully. Thanks Sanjeev Gupta