|MadSci Network: Anatomy|
To my knowledge there have been no experimental studies looking at this question. However, based on reports of the number of foreign bodies that end up in the esophagus vs. in the airway (trachea/bronchi) it seems that the esophagus is the more likely tract by about 2 to 1. A Japanese group specifically reported the location of foreign bodies they have remove over several years. They found that that the most involved sites were the nose (39.4%) and the pharynx (38.4%), followed by the esophagus (12.9%) and the trachea-bronchi (6.5%).
Higo R, Matsumoto Y, Ichimura K, Kaga K. (2003) Foreign bodies in the aerodigestive tract in pediatric patients. Auris Nasus Larynx. 30(4):397-401.
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