This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Unknown
Retropharyngeal space extends from base of skull to: 
Select and explain. 
A. Hyoid bone, B. Bifurcation of trachea, C. Angle of mandible, D. Cricoid cartilage
B: Bifurcation of trachea
Answer: B: Bifurcation of trachea 
Explanation: Retropharyngeal space: It lies behind the pharynxbetween the buccopharyngeal fascia covering pharyngeal constrictor muscles and the pre vertebral fascia.
It extendsfrom the base of skull to the bifurcation of trachea.
Thespace is divided into two lateral compartments (spaces ofGillette) by a fibrous raphe.
Each lateral spacecontains retropharyngeal nodes which usually disappear at3-4 years of age.
Parapharyngeal space communicates withthe retropharyngeal space.
Infection of retropharyngealspace can pass down behind the oesophagus into themediastinum .