Thoracic Muscles

Question 1

What is the origin of the Pectoralis Major?

Answer 1

Sternum, Clavicle, Costal Margins.

Question 2

What is the insertion of the Pectoralis Major?

Answer 2

Intertubular groove of the humerus

Question 3

What are the actions of the Pectoralis Major?

Answer 3

Flexion, adduction, and medial rotation of humerus.

Question 4

What innervates the Pectoralis Major?

Answer 4

Medial pectoral nerve (C8-T1) and lateral pectoral nerve (C5-C7).

Question 5

What is the origin of the Pectoralis Minor?

Answer 5

Ribs 3-5

Question 6

What is the insertion of the Pectoralis Minor?

Answer 6

Coracoid process of the scapula.

Question 7

What are the actions the Pectoralis Minor?

Answer 7

Stabilizes scapula against posterior thoracic wall.

Question 8

What innervates the Pectoralis Minor?

Answer 8

Medial pectoral nerve (C8-T1).

Question 9

What is the origin of the Serratus Anterior?

Answer 9

Ribs 1-8

Question 10

What is the insertion of the Serratus Anterior?

Answer 10

Medial margin of the scapula.

Question 11

What are the actions of the Serratus Anterior?

Answer 11

Scapular abduction and stabilizer of the scapula against the thoracic wall.

Question 12

What innervates the Serratus Anterior?

Answer 12

Long thoracic nerve

Question 13

What is the origin of the Subclavius?

Answer 13

Medially at Rib 1

Question 14

What is the insertion of the Subclavius?

Answer 14

Laterally at subclavian groove

Question 15

What are the actions of the Subclavius?

Answer 15

Pulls clavicle inferiorly and anteriorly, stabilizes sternoclavicular joint, and depress tip of shoulder.

Question 16

What innervates the Subclavius?

Answer 16

Subclavius nerve

Question 17

What are the superficial thoracic muscles?

Answer 17

Pectoralis Major, and Minor, Serratus Anterior, and Subclavius

Question 18

What are the deep thoracic muscles?

Answer 18

External, Internal, and Innermost Intercostals

Question 19

What is the origin of the external intercostals?

Answer 19

Inferior border of superior rib

Question 20

What is the insertion of the external intercostals?

Answer 20

Superior border of the inferior rib

Question 21

What are the actions of the external intercostals?

Answer 21

Elevates ribs to expand chest capacity during inhalation.

Question 22

What is the origin of the internal intercostals?

Answer 22

Superior border of inferior rib

Question 23

What is the insertion of the internal intercostals?

Answer 23

Inferior border of superior rib

Question 24

What are the actions of the internal intercostals?

Answer 24

Depress the ribs to decrease chest capacity during expiration.

Question 25

What are the actions of the innermost intercostals?

Answer 25

Function of the muscles is expiration because these muscles depress the ribs caudally.

Question 26

What is the innervation of the deep thoracic muscles?

Answer 26

Intercostal nerves