Trachea Anatomy: From Larynx to Main Bronchi—Structure, Relations, and Clinical Relevance

The trachea (windpipe) is a 10–12 cm fibroelastic tube connecting the larynx (C6 level) to the carina (T4–T5 / sternal angle), where it bifurcates into the right and left main bronchi.

Structural Features

• 16–20 C‑shaped hyaline cartilage rings: Prevent collapse during inspiration; open posteriorly (membranous wall) adjacent to esophagus.
• Trachealis muscle: Smooth muscle bridging posterior gap; contracts during coughing to narrow lumen and increase expiratory flow.
• Mucosa: Pseudostratified ciliated columnar epithelium with goblet cells → mucociliary escalator.
• Adventitia: Connective tissue anchoring to surrounding structures.

Key Anatomic Relations

• Anterior: Thyroid isthmus (2nd–3rd rings), thymus (inferior), brachiocephalic veins, aortic arch, manubrium.
• Posterior: Esophagus (entire length), recurrent laryngeal nerves (in tracheoesophageal grooves).
• Right lateral: Right lung/pleura, azygos vein, right vagus nerve.
• Left lateral: Left lung/pleura, aortic arch, left common carotid, left subclavian, left recurrent laryngeal nerve.

Clinical Correlates

• Tracheostomy: Usually between 2nd–4th rings; avoid cricoid (subglottic stenosis risk).
• Tracheomalacia: Cartilage softening → expiratory collapse; stridor, recurrent infections.
• Tracheoesophageal fistula: Congenital or post‑intubation; communication with esophagus.
• Thyroid surgery risk: Recurrent laryngeal nerve injury → vocal fold paralysis.

Bronchoscopy visualizes tracheobronchial tree; CT angiography evaluates vascular compression.