Muscles of the Thorax and Abdomen: Muscles of the Thoracic Wall

Question 1

Pectoralis Major Proximal Attachment

Answer 1

Clavicular head: Medial end of the clavicle

Sternocostal head: Anterior sternum and costal cartilages of the first 6 ribs

Question 2

Pectoralis Major Distal Attachment

Answer 2

Lateral lip of the intertubercular groove of the humerus

Question 3

Pectoralis Major Innervation

Answer 3

Medial and lateral pectoral nerves [C5,C6,C7,*C8,T1]

Question 4

Pectoralis Major Action

Answer 4

All fibers:
Medially rotate the shoulder
Adduct the shoulder
Clavicular head:
-Flexes the shoulder
-Horizontally adducts the shoulder
Sternocostal head:
-Extends the shoulder

Question 5

Pectoralis Minor Proximal Attachment

Answer 5

Ribs 3-5

Question 6

Pectoralis Minor Distal Attachment

Answer 6

Coracoid process of the scapula

Question 7

Pectoralis Minor Innervation

Answer 7

Medial pectoral [C8,T1]

Question 8

Pectoralis Minor Action

Answer 8

Tilts the scapula anteriorly
Depresses the shoulder girdle
Assists with:
-Elevation of ribs during forced inhalation

Question 9

Subclavius Proximal Attachment

Answer 9

Junction of the 1st rib and 1st costal cartilage

Question 10

Subclavius Distal Attachment

Answer 10

Inferior surface of the middle of the clavicle

Question 11

Subclavius Innervation

Answer 11

Nerve to subclavius [*C5,C6]

Question 12

Subclavius Action

Answer 12

Depresses the clavicle

Stabilizes the sternoclavicular joint

Question 13

External Intercostal Proximal Attachment

Answer 13

Inferior border of the ribs above

Question 14

External Intercostal Distal Attachment

Answer 14

Superior border of the ribs below

Question 15

External Intercostal Innervation

Answer 15

Intercostal nerves T1-T11

Question 16

External Intercostal Action

Answer 16

Elevates ribs to assist with inhalation

Question 17

Internal Intercostal Proximal Attachment

Answer 17

Inferior border of the ribs above

Question 18

Internal Intercostal Distal Attachment

Answer 18

Superior border of the ribs below

Question 19

Internal Intercostal Innervation

Answer 19

Intercostal nerves T1-T11

Question 20

Internal Intercostal Action

Answer 20

Depresses ribs to assist with exhalation

Question 21

Innermost Intercostal Proximal Attachment

Answer 21

Inferior border of the ribs above

Question 22

Innermost Intercostal Distal Attachment

Answer 22

Superior border of the ribs below

Question 23

Innermost Intercostal Innervation

Answer 23

Intercostal nerves T1-T11

Question 24

Innermost Intercostal Action

Answer 24

Probably depresses ribs to assist with exhalation

Question 25

Transversus Thoracis Proximal Attachment

Answer 25

Inner surface of the sternum

Question 26

Transversus Thoracis Distal Attachment

Answer 26

Inner surfaces of costal cartilages 2-6

Question 27

Transversus Thoracis Innervation

Answer 27

Intercostal nerves 2-6

Question 28

Transversus Thoracis Action

Answer 28

Depresses ribs to assist with exhalation

Question 29

Diaphragm Proximal Attachment

Answer 29

Xiphoid process, costal margins, fascia over the quadratus lumborum and psoas major mm., and vertebral bodies L1-L3

Question 30

Diaphragm Distal Attachment

Answer 30

Central tendon of the diaphragm

Question 31

Diaphragm Innervation

Answer 31

Phrenic nerve (C3-C5)

Question 32

Diaphragm Action

Answer 32

Draws the central tendon downward during inspiration