Question 1

Which of the following best describes a third-class lever in the human body, and why are third-class levers most common in skeletal muscle movement?

Accepted Answer

The fulcrum is between the applied force and the load; they maximize speed and range of motion.

Question 2

A patient is unable to abduct their arm at the shoulder joint. Which muscle is most likely impaired?

Accepted Answer

Deltoid

Question 3

Which muscle arrangement allows for the greatest range of motion but the least power?

Accepted Answer

Parallel

Question 4

During chewing, which muscle is primarily responsible for elevating the mandible?

Accepted Answer

Masseter

Question 5

A muscle that assists the prime mover in performing its action is called a:

Accepted Answer

Synergist

Question 6

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

Accepted Answer

The origin is the fixed attachment, and the insertion is the movable attachment.

Question 7

Which group of muscles is primarily responsible for extension at the knee joint?

Accepted Answer

Quadriceps femoris

Question 8

If the phrenic nerve is damaged, which muscle's function would be most directly affected, and what would be the primary consequence?

Accepted Answer

Diaphragm; impaired breathing

Question 9

Which muscle is NOT part of the hamstring group?

Accepted Answer

Rectus femoris

Question 10

A patient presents with difficulty in plantar flexion and eversion of the foot. Which muscle is most likely affected?

Accepted Answer

Fibularis longus

Question 11

Which of the following muscles is responsible for lateral rotation of the thigh at the hip joint?

Accepted Answer

Piriformis

Question 12

Which muscle group is primarily responsible for flexion of the elbow joint?

Accepted Answer

Biceps brachii and brachialis

Question 13

Which of the following best describes the action of the orbicularis oris muscle?

Accepted Answer

Closes and protrudes the lips

Question 14

Which muscle is primarily responsible for flexion and adduction at the shoulder joint?

Accepted Answer

Pectoralis major

Question 15

A patient has difficulty pronating their forearm. Which muscle is most likely impaired?

Accepted Answer

Pronator teres

Question 16

Which of the following is a function of the pelvic diaphragm muscles?

Accepted Answer

Support of pelvic organs

Question 17

Which muscle is responsible for raising the soft palate during swallowing?

Accepted Answer

Palatal muscles

Question 18

Which of the following best describes the role of the trapezius muscle?

Accepted Answer

Affects the positions of the shoulder girdle, head, and neck

Question 19

Which muscle group is most important for stabilizing the scapula during upper limb movements?

Accepted Answer

Rhomboid and serratus anterior

Question 20

Which of the following equations best represents the mechanical advantage (MA) of a lever, and what does a value of $$MA \u003e 1$$ indicate?

Accepted Answer

$$MA = \frac{Length_{effort~arm}}{Length_{resistance~arm}}$$; $$MA \u003e 1$$ means the lever increases force

Chapter 11: The Muscular System – Structure, Function, and Integration

Study Guide - Practice Questions