What is present in the retropharyngeal space of Gillette?
Retropharyngeal Space is a potential space between the buccopharyngeal fascia and the prevertebral fascia, extending from the base of the skull to the superior mediastinum. 
It permits movement of the pharynx, larynx, trachea, and esophagus during swallowing.
Platysma
Loose areolar tissue and lymph nodes
Vertebrae
Hypoglossal nerve