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    Trachea

    Reviewed by our medical team

    Tube that carries air to bronchi.

    1. Overview

    The trachea, commonly known as the "windpipe," is a large tubular structure that forms a crucial part of the lower respiratory tract. It functions as the main airway conduit, transporting inhaled air from the larynx to the bronchi. Structurally reinforced by cartilage, the trachea plays a vital role in maintaining airway patency, filtering inhaled air, and facilitating effective ventilation.

    2. Location

    The trachea is located in the anterior neck and superior mediastinum, extending from the cricoid cartilage (C6) to the carina (T4–T5 intervertebral disc level), where it bifurcates into the right and left primary bronchi.

    • Anteriorly: Lies deep to the skin, sternohyoid and sternothyroid muscles

    • Posteriorly: Lies against the esophagus

    • Laterally: Flanked by the lobes of the thyroid gland, carotid arteries, and recurrent laryngeal nerves

    3. Structure

    The trachea is approximately 10–12 cm long and about 2 cm in diameter in adults. Its wall is composed of several layers:

    • Mucosa: Lined by pseudostratified ciliated columnar epithelium with goblet cells that trap and move debris

    • Submucosa: Contains seromucous glands and connective tissue

    • Cartilaginous layer: Consists of 16–20 C-shaped hyaline cartilage rings that prevent airway collapse; the open part of the ring faces posteriorly

    • Trachealis muscle: A band of smooth muscle connecting the open ends of cartilage posteriorly, allowing for esophageal expansion during swallowing

    • Adventitia: Outer connective tissue layer anchoring the trachea to nearby structures

    4. Function

    The trachea performs several essential functions in the respiratory system:

    • Air conduction: Serves as the main passageway for air to travel from the larynx to the bronchi

    • Mucociliary clearance: Ciliated epithelium and mucus-producing goblet cells trap inhaled particles and move them upward toward the pharynx

    • Structural integrity: Cartilage rings keep the airway open during inhalation and exhalation

    • Air humidification and warming: The mucosa helps warm and moisten incoming air before it reaches the lungs

    5. Physiological Role(s)

    In pulmonary physiology, the trachea plays critical roles such as:

    • Airflow resistance regulation: Trachealis muscle can contract or relax slightly to modulate airflow resistance

    • Protective reflexes: Inhaled irritants stimulate cough reflexes originating from the trachea to expel harmful particles

    • Immune surveillance: Mucosal immune cells and lymphatic tissue help detect and respond to pathogens

    • Pressure buffering: Helps maintain stable airway pressure during high-flow respiratory events (e.g., coughing, sneezing)

    6. Clinical Significance

    Tracheitis

    Inflammation of the tracheal lining, typically caused by bacterial or viral infections. Presents with:

    • Stridor (high-pitched breathing)

    • Hoarseness

    • Fever and productive cough

    May lead to airway narrowing, especially in children.

    Tracheomalacia

    A condition characterized by weakness and collapse of the tracheal wall, especially during expiration. Can be congenital or acquired. Symptoms include:

    • Wheezing

    • Chronic cough

    • Recurrent respiratory infections

    Treatment depends on severity and may include CPAP, stenting, or surgery.

    Tracheal Stenosis

    Abnormal narrowing of the trachea due to inflammation, trauma, prolonged intubation, or tumors. Can lead to:

    • Dyspnea

    • Stridor

    • Exercise intolerance

    Treated with dilation, laser therapy, or tracheal resection.

    Tracheostomy

    A surgical procedure where an opening is made into the trachea to establish an alternate airway. Commonly performed in:

    • Prolonged intubation

    • Upper airway obstruction

    • Neuromuscular disorders affecting breathing

    The trachea is the target structure for insertion of the tracheostomy tube.

    Foreign Body Aspiration

    Inhaled objects may lodge in the trachea, especially in children, causing:

    • Sudden coughing

    • Choking

    • Stridor or cyanosis

    Requires urgent bronchoscopy for removal.

    Tracheal Tumors

    Rare but serious; may be benign (e.g., papillomas) or malignant (e.g., squamous cell carcinoma, adenoid cystic carcinoma). Symptoms often appear late and include:

    • Persistent cough

    • Hemoptysis

    • Dyspnea and stridor

    Management involves imaging, biopsy, and surgical or oncologic treatment.

    Did you know? Breathing rates slow down during sleep, but the lungs continue to provide oxygen and remove carbon dioxide from the blood.