Question

multiple choice question

which muscle is the internal intercostal?

a
b
c
d

Explanation:

Identify the anatomical structures labeled in the diagram

Using the Intercostal Muscles knowledge point

• A points to the deeper layer of muscles between the ribs, where the fibers run downward and backward (obliquely posterior-lateral). This represents the internal intercostal muscles.
• B points to the superficial layer of muscles between the ribs, where the fibers run downward and forward (obliquely anterior-medial). This represents the external intercostal muscles.
• C points to the pectoralis minor muscle (or deep thoracic wall muscles/serratus anterior depending on the layer shown).
• D points to the serratus anterior muscle on the lateral thoracic wall.

Match the target muscle to the correct label

Using the Intercostal Muscles knowledge point

• The question asks: "Which muscle is the internal intercostal?"
• Based on the fiber direction and depth shown on the left side of the rib cage (anatomical left, which is the right side of the image), label A points to the internal intercostals.
• Therefore, the correct option is A.

Answer:

• (A) A (Correct answer)
• (B) B
• (C) C
• (D) D