Question 1

Which of the following best describes the difference between intrinsic and extrinsic back muscles?

Accepted Answer

Intrinsic muscles are located deep and act directly on the vertebral column, while extrinsic muscles are superficial and connect the vertebral column to the upper limb or thoracic cage.

Question 2

Which muscle group is most responsible for generating lateral flexion of the vertebral column, and why?

Accepted Answer

The erector spinae group, because their long, vertically oriented fibers are positioned laterally, allowing effective lateral flexion.

Question 3

Which of the following correctly lists the three columns of the erector spinae from lateral to medial?

Accepted Answer

Iliocostalis, longissimus, spinalis

Question 4

A patient presents with difficulty extending their neck bilaterally. Which intrinsic back muscle group is most likely affected?

Accepted Answer

Spinotransversales (splenius muscles)

Question 5

During forced expiration, which thoracic muscle is primarily responsible for depressing the ribs?

Accepted Answer

Serratus posterior inferior

Question 6

Which abdominal muscle has fibers that run horizontally and is primarily responsible for compressing the abdominal cavity?

Accepted Answer

Transversus abdominis

Question 7

What is the primary action of the diaphragm when its muscle fibers contract?

Accepted Answer

It flattens and descends, increasing thoracic volume and causing inspiration.

Question 8

Which of the following best describes the orientation of the external oblique muscle fibers?

Accepted Answer

They run diagonally downward and medially from the lower ribs to the linea alba.

Question 9

A pneumothorax occurs when air enters the pleural cavity. Which anatomical structure is directly compromised, leading to lung collapse?

Accepted Answer

The parietal pleura is torn, breaking the airtight seal.

Question 10

Which muscle group is most important for stabilizing the vertebrae during movement, especially due to their short, oblique fibers?

Accepted Answer

Transversospinales

Question 11

Which of the following is NOT a function of the axial musculature?

Accepted Answer

Stabilizing or moving the appendicular skeleton

Question 12

Which muscle forms the most anterior wall of the abdomen and has vertically oriented fibers?

Accepted Answer

Rectus abdominis

Question 13

Which of the following best describes the action of the internal intercostal muscles?

Accepted Answer

They depress the ribs during forced expiration.

Question 14

Which muscle group is named according to the pattern 'origin to insertion' and has a superficial layer with fibers running from the spine to the transverse processes?

Accepted Answer

Spinotransversales

Question 15

Which of the following muscles is most involved in lateral rotation of the vertebral column when contracted unilaterally?

Accepted Answer

External oblique

Question 16

Which of the following is a tendinous structure found in the anterior abdominal wall that separates the left and right rectus abdominis muscles?

Accepted Answer

Linea alba

Question 17

If the erector spinae muscles contract eccentrically during trunk flexion, what is their primary function?

Accepted Answer

They control and slow down trunk flexion, preventing sudden collapse.

Question 18

Which muscle group is most likely to be affected if a patient has difficulty stabilizing the vertebral column during twisting movements?

Accepted Answer

Transversospinales

Question 19

Which of the following equations best represents the relationship between pressure and volume in the thoracic cavity during diaphragm contraction (inspiration)?

Accepted Answer

$$P_1$$ $$V_1$$ = $$P_2$$ $$V_2$$

Question 20

Which muscle group is most likely to be involved in both extension and lateral flexion of the vertebral column due to its long, vertically oriented fibers?

Accepted Answer

Erector spinae

Myology of the Vertebral Column & Trunk: Axial Musculature, Back, Thorax, and Abdomen

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