During the acute operation of a patient after a

traffic accident and after repeated unsuccessful intubation, an acute coniotomy

is performed (cutting the conic ligament and securing the airway through this

opening in the larynx). This is subsequently replaced by a tracheotomy due to

the expected long-term artificial lung ventilation. During this procedure, 2-3

cartilaginous rings of the trachea are cut. What type of cartilage is here?