Topography
It begins at the cricoid cartilage and descends along the ventral midline of the neck, with the esophagus dorsal and slightly to the left in the caudal neck, and the lobes of the thyroid gland on either side of its first rings. It enters the thorax through the cranial thoracic aperture, runs through the cranial mediastinum and divides over the heart base into the right and left principal bronchi.
Structure
- Tracheal cartilages: C-shaped rings of hyaline cartilage, open dorsally.
- Trachealis muscle: joins the ends of the cartilages; in carnivores it attaches to their outer surface.
- Mucosa: ciliated pseudostratified epithelium with goblet cells, part of the mucociliary apparatus.
Clinical relevance
- Intubation: the feline larynx is prone to laryngospasm, so topical lidocaine is usually applied before intubation. An overinflated endotracheal tube cuff or moving the intubated cat can tear the trachea, with subcutaneous emphysema and pneumomediastinum days after anaesthesia.
- Feline asthma and chronic bronchitis: tracheal or bronchoalveolar lavage through the endotracheal tube confirms eosinophilic or neutrophilic inflammation.
- Tracheal obstruction: tracheal collapse is rare in the cat (unlike the dog); obstructions are mostly due to intraluminal masses (lymphoma, carcinoma) or foreign bodies.
- Brachycephalic syndrome: in Persians and other brachycephalic breeds the main problem is stenotic nares and nasal conformation; tracheal involvement is far less relevant than in the dog.
3D model
Schematic tube from the larynx, with the principal bronchi (illustrative fidelity), placed from landmarks on the skeleton and the scanned organs. It shows topography, not fine morphology.