Question 1

Which muscle group is primarily responsible for extending and laterally flexing the vertebral column, and is composed of the iliocostalis, longissimus, and spinalis muscles?

Accepted Answer

Erector spinae muscles

Question 2

A patient presents with difficulty abducting their arm at the shoulder. Damage to which muscle or its innervation is most likely responsible?

Accepted Answer

Deltoid (axillary nerve)

Question 3

Which muscle originates from the occipital bone and spinous processes of C7-T12, and is responsible for elevating, retracting, and depressing the scapula?

Accepted Answer

Trapezius

Question 4

The main action of the latissimus dorsi muscle is best described as:

Accepted Answer

Adduction and extension of the humerus

Question 5

Which muscle is responsible for compressing the abdomen, depressing the ribs, and flexing the spine?

Accepted Answer

External oblique

Question 6

A torn pectoralis major muscle would most likely impair which of the following actions?

Accepted Answer

Flexion, adduction, and medial rotation at the shoulder

Question 7

Which nerve innervates the trapezius muscle?

Accepted Answer

Accessory nerve

Question 8

A patient with a lesion of the thoracodorsal nerve would have difficulty performing which movement?

Accepted Answer

Adduction and extension of the humerus

Question 9

Which muscle is primarily responsible for protracting the scapula, as seen in a punching motion?

Accepted Answer

Serratus anterior

Question 10

Which of the following best describes the insertion of the pectoralis major muscle?

Accepted Answer

Greater tubercle and intertubercular groove of humerus

Question 11

Which muscle, when contracted, elevates the ribs and assists in forced inspiration?

Accepted Answer

External intercostals

Question 12

A patient is unable to retract their scapula. Which muscle is most likely weakened?

Accepted Answer

Rhomboid muscles

Question 13

Which muscle originates from the acromion and spine of the scapula and inserts on the deltoid tuberosity?

Accepted Answer

Deltoid

Question 14

Which of the following muscles is NOT part of the erector spinae group?

Accepted Answer

Quadratus lumborum

Question 15

Which muscle is responsible for the main action of adduction and medial rotation of the humerus, and is innervated by the thoracodorsal nerve?

Accepted Answer

Latissimus dorsi

Question 16

Which of the following best describes the action of the external oblique muscle?

Accepted Answer

Compresses abdomen, depresses ribs, flexes spine

Question 17

A patient with a torn pectoralis major muscle would have difficulty with which of the following activities?

Accepted Answer

Pushing open a heavy door

Question 18

Which muscle is responsible for elevating the scapula and is innervated by the accessory nerve?

Accepted Answer

Trapezius

Question 19

Which muscle, when contracted, depresses and protracts the shoulder?

Accepted Answer

Pectoralis minor

Question 20

Which muscle is most likely to be involved in a case of winged scapula due to nerve injury?

Accepted Answer

Serratus anterior

Muscles of the Torso and Shoulder: Structure, Function, and Clinical Relevance

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