Intercostal muscles are found in the ------ region

1. Analyze the question The question asks where the intercostal muscles are located in the body.

2. Explain the concept Break the word into parts:

• "Inter" means between
• "Costal" refers to the ribs (Latin costa = rib)

So intercostal muscles are the muscles between the ribs. The ribs form the rib cage, which protects the heart and lungs in the chest (thoracic) region.

3. Step-by-step solution

• Intercostal muscles lie in the spaces between adjacent ribs.
• The ribs make up the thoracic cage, which is the chest.
• Therefore, the intercostal muscles are in the chest region.

Their function in breathing:

• External intercostal muscles contract during inhalation. This raises the ribs upward and outward and increases the volume of the thoracic cavity, so air rushes into the lungs.
• Internal intercostal muscles contract during forced exhalation. This pulls the ribs downward and inward, reducing the chest volume and pushing air out.

(Normal quiet exhalation is mostly passive, as the muscles relax and the diaphragm returns to its dome shape.)

4. Identify the answer The correct option is B. chest.

5. Exam tip Break difficult biological terms into their parts. Inter = between, costal = ribs, so "between the ribs" means chest. You can use the same trick for other terms, such as intercellular (between cells) and subcostal (below the ribs).