The trachea, commonly called the windpipe, is the tube that carries air between your throat and your lungs. It runs about 4 inches (10 centimeters) long and roughly 1 inch (2.5 centimeters) wide in adults, sitting just in front of your esophagus (the tube that carries food to your stomach). Despite its simple job description, the trachea is a surprisingly well-engineered structure with built-in defenses against infection and debris.
Where the Trachea Sits in Your Body
The trachea begins at the bottom of the larynx (your voice box), at about the level of the sixth or seventh cervical vertebra in your neck. From there it drops straight down through the center of your chest, passing behind the breastbone. At the level of the fourth or fifth thoracic vertebra, roughly where the upper and lower portions of the breastbone meet, the trachea splits into two branches called the left and right main bronchi. The point where it divides is called the carina, and it sits slightly to the right of the midline.
This means the trachea spans two body regions: the upper portion sits in the neck, while the lower portion descends into the chest cavity. Major blood vessels, nerves, and the esophagus all run alongside it in tight proximity, which is why injuries or swelling in this area can become serious quickly.
How the Trachea Stays Open
If the trachea were made entirely of soft tissue, it would collapse every time you inhaled, much like a drinking straw being sucked shut. To prevent that, 16 to 20 rings of firm cartilage wrap around the front and sides of the tube. These rings are U-shaped (sometimes described as C-shaped), meaning they’re open along the back. Each ring is connected to the next by flexible ligaments, giving the trachea a ridged texture you can feel at the front of your neck just below the Adam’s apple.
The open back of each ring is filled with smooth muscle and connective tissue, which sits against the esophagus. This design serves two purposes: the cartilage keeps the airway from collapsing, while the flexible muscular back wall allows the esophagus to expand slightly when you swallow a large bite of food.
The Lining That Traps and Removes Debris
The inside of the trachea is lined with a specialized layer of cells that functions like a self-cleaning conveyor belt. Three main cell types work together here. Ciliated cells are the most abundant, making up more than half the lining. Each one is topped with 200 to 300 tiny hair-like projections called cilia. Goblet cells are scattered among them, producing a thin layer of sticky mucus that coats the airway surface. Basal cells sit at the base of the lining and act as stem cells, capable of replacing damaged ciliated or goblet cells as needed.
The mucus layer traps dust, pollen, bacteria, and other particles you inhale. Beneath it sits a thinner, watery layer about 7 micrometers deep that lubricates the cilia so they can move freely. The cilia beat in coordinated waves, each one slightly out of phase with its neighbor, creating a ripple effect that pushes the mucus and its trapped debris upward toward the throat. From there, you either swallow it (usually without noticing) or cough it out. This entire system is called mucociliary clearance, and it’s your lungs’ primary built-in defense mechanism. When the watery layer beneath the mucus gets too thin, from dehydration or certain diseases, the mucus collapses onto the cilia and traps them, stalling the whole system.
The Cough Reflex Starts Here
The trachea is one of the most cough-sensitive areas in your entire airway. Nerve endings concentrated in the lining of the trachea, larynx, and the carina (where the trachea splits) respond to mechanical irritation, such as an inhaled crumb or a surge of mucus. These specialized nerve terminals are arranged in complex branching patterns along the walls of the airway, positioned to detect anything that shouldn’t be there. When triggered, they send signals that produce the explosive burst of air you recognize as a cough. Notably, these particular cough receptors exist only in the upper airways (trachea, larynx, and main bronchi), not deeper in the lungs, which rely on different sensory mechanisms.
How the Trachea Changes With Age
A newborn’s trachea is far smaller and softer than an adult’s, which is one reason airway problems in infants can escalate quickly. In children, the trachea’s width tends to be slightly wider side-to-side than front-to-back until around age 6, when the dimensions even out. Boys’ and girls’ tracheas grow at the same rate until about age 14, when growth typically stops in girls. In boys, the trachea continues to widen (though not lengthen) for some time after they stop growing in height. This is one reason adult men generally have noticeably larger airways than adult women.
Common Tracheal Problems
Tracheal stenosis, a narrowing of the trachea, is one of the more significant conditions affecting this structure. It can develop after prolonged use of a breathing tube during hospital stays, after a tracheostomy, or from direct trauma to the airway. Certain autoimmune and inflammatory diseases can also cause the trachea to narrow over time. The hallmark symptom is noisy breathing, particularly a high-pitched sound during inhalation called stridor. As the narrowing worsens, breathing becomes visibly effortful, sometimes with tugging of the skin above the breastbone or between the ribs during each breath.
Other conditions that affect the trachea include tracheomalacia, where the cartilage rings are too soft to hold the airway open properly (more common in premature infants), and tracheal infections like bacterial tracheitis, which can cause rapid swelling of the airway lining.
What a Tracheostomy Does
A tracheostomy is a surgically created opening through the front of the neck directly into the trachea. The procedure of cutting into the trachea is technically called a tracheotomy, while the opening itself is the tracheostomy, though the two terms are often used interchangeably. This opening allows air to reach the lungs while bypassing the mouth, nose, and throat entirely. It may be temporary, used during recovery from surgery or a severe injury, or permanent in cases where the upper airway is permanently blocked or a person needs long-term mechanical ventilation. A small tube is placed into the opening to keep it from closing, and air flows directly through it with each breath.