Question 1

Which muscle is highlighted in the second image, and what is its primary action?

Accepted Answer

Pectoralis major; flexes, adducts, and medially rotates the arm

Question 2

What is the origin of the muscle labeled 'Biceps femoris' in the fourth image?

Accepted Answer

Ischial tuberosity

Question 3

Which muscle is responsible for closing the eyelids, and what is its insertion?

Accepted Answer

Orbicularis oculi; skin of the eyelids

Question 4

In the third image, which muscle elevates the ribcage during inhalation?

Accepted Answer

External intercostals

Question 5

A patient is unable to flex their elbow. Which muscle is most likely impaired?

Accepted Answer

Biceps brachii

Question 6

Which muscle originates from the pubic symphysis and inserts on the xiphoid process and costal cartilage?

Accepted Answer

Rectus abdominis

Question 7

What is the action of the muscle labeled 'Semitendinosus' in the fourth image?

Accepted Answer

Flexes knee and extends thigh

Question 8

Which muscle is known as the 'kissing muscle' and what is its action?

Accepted Answer

Orbicularis oris; closes and purses the lips

Question 9

A person has difficulty raising their arm sideways (abduction). Which muscle is most likely affected?

Accepted Answer

Deltoid

Question 10

Which muscle originates from the clavicle and sternum and inserts on the greater tubercle of the humerus?

Accepted Answer

Pectoralis major

Question 11

What is the action of the muscle that inserts on the medial border of the scapula and originates from ribs 1-8?

Accepted Answer

Rotates scapula

Question 12

Which muscle is responsible for plantar flexion and inserts on the calcaneus?

Accepted Answer

Gastrocnemius

Question 13

A patient cannot extend their elbow. Which muscle is most likely damaged?

Accepted Answer

Triceps brachii

Question 14

Which muscle originates from the sacrum, coccyx, and ilium and inserts on the iliotibial tract?

Accepted Answer

Gluteus maximus

Question 15

What is the action of the muscle that originates from the anterior iliac spine and inserts on the proximal tibia?

Accepted Answer

Flexes, abducts, and laterally rotates thigh

Question 16

Which muscle is responsible for trunk rotation and inserts on the linea alba?

Accepted Answer

External oblique

Question 17

A patient has difficulty with dorsiflexion of the foot. Which muscle is most likely affected?

Accepted Answer

Tibialis anterior

Question 18

Which muscle originates from the thoracic and lumbar vertebrae, ribs, and iliac crest and inserts on the proximal humerus?

Accepted Answer

Latissimus dorsi

Question 19

What is the action of the muscle that originates from the manubrium and clavicle and inserts on the mastoid process?

Accepted Answer

Flexes and laterally rotates head

Question 20

Which muscle originates from the distal humerus and inserts on the styloid process of the radius?

Accepted Answer

Brachioradialis

Skeletal Muscles: Origins, Insertions, and Actions

Study Guide - Practice Questions