Question 1

Which of the following best describes the difference between the origin and insertion of a skeletal muscle?

Accepted Answer

The origin is the fixed end of the muscle, while the insertion is the end that moves during contraction.

Question 2

A patient is unable to raise their eyebrows. Which muscle is most likely impaired?

Accepted Answer

Epicranius (frontal belly)

Question 3

During a sit-up, which muscle is primarily responsible for flexing the vertebral column?

Accepted Answer

Rectus abdominis

Question 4

If the masseter muscle is paralyzed, which action would be most affected?

Accepted Answer

Closing the jaw

Question 5

Which muscle originates from the clavicle and sternum and inserts on the humerus, and what is its primary action?

Accepted Answer

Pectoralis major; flexion of the arm

Question 6

A person is unable to turn their head to the left or right. Which muscle is most likely affected?

Accepted Answer

Sternocleidomastoid

Question 7

Which muscle is responsible for blinking and what is its origin?

Accepted Answer

Orbicularis oculi; maxillary bone

Question 8

A patient presents with difficulty abducting their arm at the shoulder. Which muscle is most likely compromised?

Accepted Answer

Deltoid

Question 9

Which of the following best explains why the external oblique muscle is important for trunk movement?

Accepted Answer

It rotates and laterally flexes the trunk.

Question 10

If a person cannot smile, which muscle is most likely not functioning properly?

Accepted Answer

Zygomaticus

Question 11

Which muscle has its origin on the sternum and temporal bone and is responsible for head rotation?

Accepted Answer

Sternocleidomastoid

Question 12

A patient is unable to close their mouth. Which muscle is most likely affected and what is its insertion?

Accepted Answer

Masseter; mandible

Question 13

Which muscle is primarily responsible for the action of breathing by elevating the ribs?

Accepted Answer

Intercostals (internal/external)

Question 14

A person is unable to perform a sit-up. Which muscle is most likely weak or damaged?

Accepted Answer

Rectus abdominis

Question 15

Which muscle originates from the zygomatic bone and inserts at the skin/muscle at the corner of the mouth?

Accepted Answer

Zygomaticus

Question 16

If the external oblique muscle is damaged, which movement would be most affected?

Accepted Answer

Trunk rotation

Question 17

Which muscle's action would be most directly tested by asking a patient to flex their arm at the shoulder joint?

Accepted Answer

Pectoralis major

Question 18

A patient is unable to blink. Which muscle and its origin are most likely involved?

Accepted Answer

Orbicularis oculi; maxillary bone

Question 19

Which muscle is responsible for closing the jaw and originates from the zygomatic bone?

Accepted Answer

Masseter

Question 20

A patient presents with difficulty flexing their trunk and performing sit-ups. Which muscle is most likely involved, and what is its origin?

Accepted Answer

Rectus abdominis; os coxa

Gross Anatomy of the Muscular System: Origins, Insertions, and Actions

Study Guide - Practice Questions