Skip navigation

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Results 1 - 1 of 1 for Collapsing
  1. ... contains rings of cartilage that prevent it from collapsing. Within the lungs, the trachea branches into a ...