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IGCSE · Cambridge (CIE) · 0973

Identify lungs ribs intercostal muscles and diaphragm in a diagram

Locate the organs and chest-wall structures without assigning air to muscle tissue.

Gas exchange in humans · Cambridge IGCSE 0973 · B11.1
Exam scope and assessment notes

Mapped to the named 0973 section using teaching from the corresponding single-science course. A 0973-specific review of every Core and Supplement objective is still in progress. Written practice is self-checked; it does not demonstrate supervised laboratory competence or award an official Cambridge grade. This qualification reports two grades on the 9–1 scale; confirm the entry route for your zone and exam series.

Before you begin

  • Recall the airway branches inside lungs.

Work on paper. Try each question before revealing help, and explain why your method works.

Quick readiness check

What does intercostal mean in this context?

What you will learn

  • Separate air-containing organs from supporting structures
  • Use label endpoints in the schematic

Identify lungs ribs intercostal muscles and diaphragm in a diagram

E lung, F rib, G between-rib intercostal tissue, H diaphragm. Overlapping anatomy is separated schematically.EFGHOverlapping anatomy separated
E lung, F rib, G between-rib intercostal tissue, H diaphragm. Overlapping anatomy is separated schematically. Original teaching model.

Separate air-containing organs from supporting structures

The lungs lie in the thorax, enclosed by the rib cage. Ribs are curved bones in the chest wall; intercostal muscles lie between them. The diaphragm forms the muscular boundary below the thorax. These are different structures, so an answer should not use rib and intercostal muscle as names for the same band.

Lungs contain the branching airways and alveoli. The diaphragm and intercostal muscles contribute to breathing movements, but air does not normally travel through their muscle tissue. Core identification here concerns position and structure; the Extended lessons explain their coordinated effects on volume and pressure.

Use label endpoints in the schematic

In the original chest diagram, E marks a lung, F a rib, G the intercostal tissue between ribs and H the curved diaphragm below the lungs. The ribs are shown as short bands on each side to avoid concealing the lungs; this does not mean a real rib cage consists only of these small visible segments.

The diagram is not a radiograph or a measurement of a person’s chest. It separates overlapping structures to make the labels readable. In a new view identify the diaphragm by its position below the thorax and distinguish the ribs from tissue spanning their spaces, rather than copying left or right page positions blindly.

Sources for this lesson

Pause and explain

Which structure forms the muscular boundary below the thorax?

Put the idea to work

Worked example

Read E–H in the original chest map.

Show the worked solution
  1. E is within the thorax.
  2. F and G separate bone and between-rib tissue; H is below.

Answer E lung; F rib; G intercostal muscles; H diaphragm.

Try a topic test

Choose Easy, Normal or Difficult. Save your answers and open worked review after finishing.

Test this topic →

From guided practice to a new situation

Write your answer and reasoning first. Use a hint only if you are stuck. The model solution is for self-checking; your written work is not automatically marked.

1 · Guided

Identify E, F, G and H in the chest diagram.

Give me a hint

Read each label’s endpoint.

Compare my reasoning
  1. E is a lung; F is a rib.
  2. G lies between ribs; H is the diaphragm.

E lung; F rib; G intercostal muscles; H diaphragm.

Look for these in your work

  • Identify all four
  • Distinguish bone and muscle
2 · Independent

Describe where intercostal muscles and the diaphragm lie relative to the ribs and lungs.

Give me a hint

Give positional relationships.

Compare my reasoning
  1. Intercostal muscles occupy spaces between ribs.
  2. The diaphragm lies below the lungs at the base of the thorax.

Intercostal muscles lie between ribs; the diaphragm forms the muscular floor below the lungs.

Look for these in your work

  • Locate both muscles
  • Use the correct reference structures
3 · Transfer

A student draws inspired air moving through the diaphragm into an alveolus. Correct the route.

Give me a hint

Muscle moves the chest boundary; it is not an air passage.

Compare my reasoning
  1. Air reaches alveoli through airways.
  2. The diaphragm is a muscle contributing to ventilation.

Air travels through trachea, bronchi and bronchioles to alveoli; the diaphragm is not an air passage.

Look for these in your work

  • Correct the airway route
  • Keep the muscle role distinct

Common mistakes

  • Calling intercostal tissue a rib.
  • Drawing the diaphragm inside an alveolus.
Recall without your notes

What can you explain now?

Which structure forms the muscular boundary below the thorax?

Compare with the explanation

Diaphragm

It lies beneath the lungs.

After trying it yourself, choose your next review. This is your self-assessment.

Your review choice appears on Today. Sign in to sync it across devices.

Make it stick

Draw the chest outline, place the four structures and mark which carry air.

If you needed the solution, close it and solve the problem again from a blank page. A correct answer is stronger when you can explain the reason for each step.

Keep learning Sciences — Co-ordinated (9-1)

Course scope and assessment

This 9–1 pathway maps all 152 detailed subject-content sections in the published 0973 syllabus for exams in 2028 and 2029. The course map follows the same 2028–2029 section codes as Cambridge's A*–G 0654 syllabus, while keeping 0973's grading and entry rules separate. It adapts lessons from the related single-science courses and excludes clear single-science-only topics. A 0973-specific objective-by-objective review, Core/Supplement audit, human subject-teacher review, supervised laboratory experience and cumulative assessment remain in progress. Written practice is self-checked and does not predict an official grade. The separate 2025–2027 syllabus has not been reconciled here. Cambridge lists 0973 only in a limited number of administrative zones: June in zone 3 and centres in Oman and the UAE; November in zone 3 only. Confirm entry with your centre.

StudyForA · Learn with understanding

Original teaching content and links to official sources. Check your exam year and qualification before using a resource.