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Lines and tubes on the chest X-ray: where each tip should be

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After a breathing tube, feeding tube or central line goes in, an X-ray checks where its tip lies; a wrong place can be dangerous.

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What it is

Many chest X-rays in emergency rooms and intensive care are taken to check a device. Each one has a target and typical wrong places. The endotracheal tube tip should sit in the mid trachea, a few centimetres above the carina, because it moves down when the neck flexes and up when it extends. A central venous catheter from the jugular or subclavian vein, or a PICC from the arm, should end in the lower superior vena cava or at its junction with the right atrium. A nasogastric tube must be confirmed below the diaphragm in the stomach before anything is put through it. The X-ray also looks for the complications of insertion, above all a pneumothorax after a jugular or subclavian line. Always follow the whole course of each device, not just its tip.

What to check

  • Endotracheal tube: tip about 5 cm above the carina (roughly 3–7 cm) with the head neutral; the carina usually projects at about T4–T5.
  • Central venous catheter (jugular or subclavian) and PICC: tip in the lower superior vena cava or at the cavoatrial junction.
  • The carina is a good landmark for the SVC: the cavoatrial junction lies roughly two vertebral bodies below it.
  • Nasogastric tube: stays in the midline down the oesophagus, bisects the carina, crosses the diaphragm and turns left; the tip and side holes lie well inside the stomach.
  • Chest drain: all side holes inside the chest wall, within the pleural space.

Reading it step by step (and why)

  1. List every device on the film first — it is easy to check one and forget another.
  2. ETT: find the carina, then the tip; measure the gap — too low enters the right main bronchus, too high risks extubation.
  3. ETT too low: look for left lung collapse and right lung overinflation — right main bronchus intubation is the classic error.
  4. NG tube: follow it down the midline past the carina and below the diaphragm — a tube that follows a bronchus is in the airway.
  5. NG tube tip: confirm it is in the stomach, well beyond the gastro-oesophageal junction — side holes in the oesophagus risk aspiration.
  6. Central line or PICC: follow it to the tip and locate it against the carina — a tip in the atrium or a vein in the neck is malpositioned.
  7. After a jugular or subclavian line: look carefully at the apex for a pneumothorax — it is the main early complication.
  8. Look for coils, kinks, loops or a tube in an unexpected vessel — a line crossing to the other side or up into the neck needs repositioning.
  9. Write the position of each device in the report — the team acts on it.

Common mistakes

  • Checking only the tip and missing a nasogastric tube that passed through a bronchus into the lung.
  • Missing a right main bronchus intubation because the left lung collapse was not looked for.
  • Calling a line in the SVC when it is in the azygos vein, an artery or the opposite brachiocephalic vein.
  • Forgetting that neck flexion and extension move the ETT tip down and up by a couple of centimetres.

Next step

  • Misplaced NG tube in the airway: do not use it; remove it and replace it, then confirm again on X-ray.
  • ETT in a main bronchus or too high: tell the team at once so it can be pulled back or advanced and rechecked.
  • Central line tip in the atrium, the neck or an artery, or a new pneumothorax: tell the operator or a senior immediately.
  • If the tip or the course is unclear, ask the radiologist; an extra view or a contrast check may be needed.

Test yourself

Think of the answer, then tap the question to see it.

Where should the tip of an endotracheal tube be on a chest X-ray?

In the mid trachea, about 5 cm (roughly 3–7 cm) above the carina with the head in neutral position.

Why is right main bronchus intubation more common than left?

The right main bronchus is wider, shorter and more vertical, so a tube pushed too far tends to enter it.

Where should the tip of a central venous catheter or PICC lie?

In the lower superior vena cava or at the cavoatrial junction, roughly two vertebral bodies below the carina.

What must the X-ray show before a nasogastric tube is used for feeding?

A course in the midline down the oesophagus, through the diaphragm, with the tip clearly inside the stomach, not in a bronchus or the oesophagus.

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Educational content; it does not replace a radiologist's report and is not a clinical instruction. Each study is ordered on the patient's assessment and your institution's protocols.

Sources: Endotracheal Intubation Techniques (StatPearls (NCBI Bookshelf), 2023); Central Venous Catheter Insertion (StatPearls (NCBI Bookshelf), 2025); Peripherally Inserted Central Catheter (PICC) Line Placement (StatPearls (NCBI Bookshelf), 2024); Nasogastric Tube Insertion (StatPearls (NCBI Bookshelf), 2026).

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