Muscles of the Thorax

Question 1

What are the two phases of breathing?

Answer 1

Inhalation: thoracic cavity increases in size
Exhalation: thoracic cavity decreases in size

Question 2

Muscles of the thorax that assist in breathing act primarily during what type of breathing?

Answer 2

relaxed quiet breathing

Question 3

How do the ribs move during inhalation/exhalation

Answer 3

move up during inhalation

move down during exhalation

Question 4

The muscles of the thorax include:

Answer 4

Diaphragm
External Intercostal
Internal Intercostal

Question 5

What does the diaphragm look like?

Answer 5

dome shaped muscle with superior convex surface

Question 6

What are the two portions of the diaphragm

Answer 6

Peripheral muscular portion

central tendon

Question 7

What are the three openings of the diaphragm?

Answer 7

aortic hiatus
esophageal hiatus
caval opening

Question 8

What is the aortic hiatus of the diaphragm for?

Answer 8

arota,
thoracic duct,
azygos veins

Question 9

What is the esophageal hiatus of the diaphragm for?

Answer 9

esophagus

vagus nerves

Question 10

What is the caval opening of the diaphragm for?

Answer 10

foramen for inferior vena cava

Question 11

What is the origin of the diaphragm?

Answer 11

xiphoid process
costal cartilages of rib 7-12
lumbar vertebrae and discs

Question 12

What is the insertion of the diaphragm?

Answer 12

central tendon

Question 13

What is the innervation of the diaphragm?

Answer 13

phrenic nerve

Question 14

What muscle exerts 75% of the effort for relaxed quiet breathing?

Answer 14

diaphragm

Question 15

Does the diaphragm help return blood to the heart?

Answer 15

yes

Question 16

Together with the anterolateral abdominal muscles the diaphragm helps increase the intaabdominal pressure for:

Answer 16

• helping the support of spine when weight lifting

- evacuation of contents in the organs:defecation, urination, childbirth

Question 17

How many pairs of intercostal muscles are there?

Answer 17

eleven

Question 18

What are the three layers of the intercostal muscles?

Answer 18

external, internal, innermost

Question 19

What layer of the intercostal muscles does the external intercostals occupy?

Answer 19

superficial layer

Question 20

What direction does the fibres of the external intercostals run?

Answer 20

obliquely, inferiorly, anteriorly and medially (same direction as external oblique)

Question 21

What is the origin of the external intercostals??

Answer 21

inferior border of the rib above

Question 22

What is the insertion of the external intercostals?

Answer 22

superior border of the rib below

Question 23

What are the actions of the external intercostals?

Answer 23

elevates ribs, relaxation allows the ribs to descend by gravity

Question 24

What muscle exerts 25% of the muscle effort in relaxed quiet breathing?

Answer 24

external intercostals

Question 25

What is the innervation of the external intercostals?

Answer 25

thoracic spinal nerves of T2-T12

Question 26

What layer of the intercostal muscles does the internal intercostals occupy?

Answer 26

intermediate layer

Question 27

In what direction do the fibres of the internal intercostals run?

Answer 27

superiorly, anteriorly, and medially ( same direction as internal obliques)

Question 28

What is the origin of the internal intercostals?

Answer 28

superior border of rib below

Question 29

What is the insertion of the internal intercostals

Answer 29

inferior border of the rib above

Question 30

What is the innervation of the internal intercostals

Answer 30

thoracic spinal nerves T2-T12