system
Medical AI Inquiry: You were designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.
user
In erect posture commonest siteof foreign body in bronchus
assistant
The correct answer is  Foreign bodies like pins,coins entering the trachea pass into the right bronchus,which is wider,more veical & is in line with trachea.Most of the human beings want to take the path of least resistance,so the foreign bodies in the trachea travel down into right bronchus and then into posterior basal segments of the lower lobe of the lung. Reference:B D Chaurasia's Human anatomy-Volume 1,5th edition,page no:288