Question 1

Which muscle is primarily responsible for closing the eyes, and what is its origin and insertion?

Accepted Answer

Orbicularis oculi; origin: frontal bone and maxilla, insertion: eyelids

Question 2

A patient is unable to flex their neck when both sides of a certain muscle contract. Which muscle is most likely affected?

Accepted Answer

Sternocleidomastoid

Question 3

Which muscle is the prime mover for jaw closure and what is its insertion?

Accepted Answer

Masseter; insertion: mandible

Question 4

The pectoralis major muscle is responsible for which of the following actions?

Accepted Answer

Arm flexion, adduction, and medial rotation

Question 5

Which muscle is the prime mover for protracting and holding the scapula against the chest wall?

Accepted Answer

Serratus anterior

Question 6

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

Accepted Answer

Rectus abdominis

Question 7

Which muscle is responsible for compressing the abdominal contents and is the deepest of the abdominal muscles?

Accepted Answer

Transversus abdominis

Question 8

The deltoid muscle is primarily responsible for which movement of the arm?

Accepted Answer

Abduction

Question 9

Which muscle is the antagonist to the biceps brachii and what is its primary action?

Accepted Answer

Triceps brachii; arm extension

Question 10

A patient presents with difficulty extending their fingers. Which muscle is most likely impaired?

Accepted Answer

Extensor digitorum

Question 11

Which muscle initiates abduction of the humerus and is part of the rotator cuff?

Accepted Answer

Supraspinatus

Question 12

A baseball pitcher injures a muscle responsible for lateral rotation of the arm. Which muscle is most likely affected?

Accepted Answer

Infraspinatus

Question 13

Which of the following best describes the action of the platysma muscle?

Accepted Answer

Tenses skin of neck and pulls corners of mouth inferiorly

Question 14

Which muscle is a powerful wrist flexor and inserts on metacarpals 2 and 3?

Accepted Answer

Flexor carpi radialis

Question 15

A patient has difficulty abducting their arm after a shoulder injury. Which muscle is most likely damaged?

Accepted Answer

Deltoid

Question 16

Which muscle is responsible for tensing the skin and fascia of the palm?

Accepted Answer

Palmaris longus

Question 17

Which of the following muscles is classified as a multipennate muscle based on its fascicle arrangement?

Accepted Answer

Deltoid

Question 18

Which muscle is the prime mover for arm adduction, extension, and medial rotation, and originates from the thoracic and lumbar vertebrae?

Accepted Answer

Latissimus dorsi

Question 19

A patient is unable to rotate their head to the opposite side. Which muscle is most likely affected?

Accepted Answer

Sternocleidomastoid

Question 20

Which muscle is responsible for compressing the abdominal wall and also assists in rotation and lateral flexion of the trunk?

Accepted Answer

External oblique

Muscles of the Body: Structure, Function, and Key Anatomical Features

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