Question 1

A patient presents with difficulty shrugging their shoulders and turning their head to the opposite side. Which cranial nerve is most likely damaged, and which two muscles are affected?

Accepted Answer

CN XI (Accessory); sternocleidomastoid and trapezius

Question 2

During a biceps curl, which lever class is being used, and what is the arrangement of the fulcrum, effort, and load?

Accepted Answer

Third-class lever; Fulcrum - Effort - Load

Question 3

Which muscle is primarily responsible for initiating the first 15° of shoulder abduction, and why is this clinically significant?

Accepted Answer

Supraspinatus; it is the most commonly torn rotator cuff muscle

Question 4

A patient with Bell's palsy is unable to close their eye and has drooping of the mouth. Which muscle and nerve are affected?

Accepted Answer

Orbicularis oculi and orbicularis oris; CN VII (Facial)

Question 5

Which fascicle arrangement allows for the greatest force production, and what is the trade-off in terms of range of motion?

Accepted Answer

Multipennate; highest force, lowest range of motion

Question 6

If the origin of a muscle is on the scapula and the insertion is on the radius, which movement occurs when the muscle contracts?

Accepted Answer

Elbow flexion, as the radius moves toward the scapula

Question 7

Which muscle acts as a fixator during shoulder abduction, and what is its primary function?

Accepted Answer

Rotator cuff muscles; stabilize the head of the humerus in the shoulder joint

Question 8

A patient is unable to stand on their tiptoes due to an Achilles tendon rupture. Which lever class is affected, and what is the mechanical advantage?

Accepted Answer

Second-class lever; greatest mechanical advantage for force

Question 9

Which abdominal muscle is most important for stabilizing the spine and compressing the abdomen, and what clinical condition can result from its weakness?

Accepted Answer

Transversus abdominis; low back pain and poor posture

Question 10

Which muscle is the primary flexor of the elbow, and how does its function differ from the biceps brachii?

Accepted Answer

Brachialis; produces more force for elbow flexion than biceps brachii

Question 11

Which muscle is responsible for protracting the scapula and holding it against the rib cage, and what clinical sign results from its paralysis?

Accepted Answer

Serratus anterior; winged scapula

Question 12

A patient is unable to rotate their head to the left and flex their neck. Which muscle is most likely affected, and what is its origin and insertion?

Accepted Answer

Right sternocleidomastoid; origin: manubrium and medial clavicle, insertion: mastoid process

Question 13

Which muscle arrangement is best suited for rapid, large movements but produces less force, and what is an example?

Accepted Answer

Parallel; sartorius

Question 14

Which muscle is most active during forced expiration, such as blowing up a balloon, and what is its action?

Accepted Answer

Internal intercostals; pull ribs downward

Question 15

A patient with pelvic organ prolapse and urinary incontinence is advised to perform Kegel exercises. Which muscle group is targeted, and what is its primary function?

Accepted Answer

Levator ani; supports pelvic organs and maintains continence

Question 16

Which muscle is the prime mover for elbow extension, and what is its clinical relevance in daily activities?

Accepted Answer

Triceps brachii; used in push-ups and standing from a chair

Question 17

Which muscle arrangement allows for versatile pulling in different directions, and what is an example?

Accepted Answer

Convergent; pectoralis major

Question 18

Which cranial nerve innervates the muscles of mastication, and what is a clinical sign of its dysfunction?

Accepted Answer

CN V (Trigeminal); jaw pain and difficulty chewing

Question 19

Which muscle is most important for lateral flexion of the trunk and stabilizing the pelvis, and what clinical condition is associated with its weakness?

Accepted Answer

Quadratus lumborum; low back pain and muscle spasms

Question 20

Which muscle assists the prime mover during elbow flexion by preventing unwanted motion, and what is its role called?

Accepted Answer

Brachialis; synergist

Chapter 10 – The Muscular System: Comprehensive Study Guide

Study Guide - Practice Questions

Study Guide - Flashcards