Carina of trachea

Carina tracheae

RespiratoryOrgansThorax

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What it is

A keel-shaped ridge of cartilage at the tracheal bifurcation, where the trachea divides into the two main bronchi at the level of the sternal angle (T4/T5).

Function

Splits the airflow between the two lungs; its mucosa is the most sensitive trigger zone of the cough reflex.

Size

The bifurcation angle is about 60–75°; the carina lies ~12 cm below the vocal folds and ~25 cm from the incisor teeth.

Clinical note

Widening or blunting of the carina on bronchoscopy suggests enlarged subcarinal lymph nodes or a dilated left atrium.