The trachea is a flexible tube that connects the upper airways (mouth and nose) to the lower airways (lungs).The trachea is composed of incomplete cartilage rings throughout its length. A thin membrane connects the rings to complete the circle. Commonly in small breeds, this membrane may be exuberant and hang into the lumen of the trachea and impede air flow. Other patients with collapsing trachea have a trachea that is too long and folds upon itself. The impaired airflow caused by both of these situations causes inflammation manifested by a loud, honking cough. Diagnosis of collapsing trachea is based on history (cough often occurs after exercise or periods of excitement), physical examination and demonstration of tracheal collapse on radiographs. Specialized x-ray equipment may be necessary for definitive diagnosis. Patients may have different degrees of severity of tracheal collapse. All patients with collapsing trachea must maintain an ideal body weight to minimize the pressure on the weakened trachea. Persistent collapse of the trachea predisposes patients to infections; treatment with antibiotics and cough suppressants may be necessary. Severely affected patients may require surgery for stent placement inside the trachea to prevent its collapse.