Identify lungs ribs intercostal muscles and diaphragm in a diagram
Locate the organs and chest-wall structures without assigning air to muscle tissue.
Section 11.1 · Gas exchange in humans
Exam scope and assessment notes
Core and Extended · Biology 0970, 2026–2028. Use the stated specimen features and evidence. Diagrams are schematic. Written practice is self-checked; human subject-teacher review, supervised practical competence and cumulative assessment remain pending. Cambridge states that IGCSE 0970 has the same subject content as IGCSE 0610, with 9–1 grading. This StudyForA pathway maps the 2026–2028 syllabus only. This 9–1 graded qualification is available only in a limited number of administrative zones. Confirm that your centre can enter you for this code and exam series with Cambridge International. Cambridge has published a separate syllabus for 2029. StudyForA has not reconciled that version yet; this page supports exams in 2026, 2027 and 2028 only.
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
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.
Pause and explain
Which structure forms the muscular boundary below the thorax?
Worked example
Read E–H in the original chest map.
Show the worked solution
- E is within the thorax.
- F and G separate bone and between-rib tissue; H is below.
Answer E lung; F rib; G intercostal muscles; H diaphragm.
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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.
Identify E, F, G and H in the chest diagram.
Give me a hint
Read each label’s endpoint.
Compare my reasoning
- E is a lung; F is a rib.
- 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
Describe where intercostal muscles and the diaphragm lie relative to the ribs and lungs.
Give me a hint
Give positional relationships.
Compare my reasoning
- Intercostal muscles occupy spaces between ribs.
- 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
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
- Air reaches alveoli through airways.
- 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.
What can you explain now?
Which structure forms the muscular boundary below the thorax?
Compare with the explanation
Diaphragm
It lies beneath the lungs.
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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.