A prepositional phrase is comprised of two parts, a preposition and an object of the preposition. Together, they form the prepositional phrase that is then inserted in a sentence to modify some noun or verb.
The epiglottis is a flap made of elastic cartilage tissue covered with a mucous membrane, attached to the entrance of the larynx. It projects obliquely upwards behind the tongue and the hyoid bone, pointing dorsally. It stands open during breathing, allowing air into the larynx.
Ear, Nose and Throat. The epiglottis is a small flap of cartilage attached to the end of the tongue which closes during swallowing. This prevents food particles and secretions from entering the trachea and lungs. Epiglottitis is an infection of the epiglottis and surrounding tissue. The onset and progression of epiglottitis are rapid in children.