Assertion: trachea's wall | /r/HasProperty | pars membranacea
Facets:
Source sentences:
text: There are about 15 to 20 C-shaped cartilaginous rings that reinforce the anterior and lateral sides of the trachea to protect and maintain the airway, leaving a membranous wall (pars membranacea) dorsally without cartilage where the C-shape is open.