Thoracic Muscles

Question 1

What are the intercostal muscles of the thorax?

Answer 1

-external intercostal muscles
-internal intercostal muscles

Question 2

Which intercostal muscles are used during inspiration?

Answer 2

External intercostals

Question 3

Where are the external intercostal muscles found?

Answer 3

outermost layer of thin muscles sitting in between the ribs

Question 4

Which intercostal muscles are used during expiration?

Answer 4

Internal intercostals

Question 5

Where are the internal intercostal muscles found?

Answer 5

The inner layer of thin muscles sitting in between the ribs (layer behind the external intercostal layer)

Question 6

What muscle is located on the inner wall of the anterior thoracic cage?

Answer 6

Transversus thoracis (TT)

Question 7

What does the transversus thoracis muscle do?

Answer 7

Depresses ribs to help with expiration

Question 8

Where is the diaphragm located in the thoracic cage?

Answer 8

Spans the inferior aperture of the thoracic cage,
“roof” of the abdominal cavity

Question 9

What nerve is the diaphragm innervated by?

Answer 9

Phrenic nerve (C3-5) (right and left!)
descends down on surface anterior scalene on both sides, runs along the heart and plugs into the diaphragm
(the motor/sensory components of diaphragm)

Question 10

Is the diaphragm a major muscle of inspiration or expiration?

Answer 10

INSPIRATION

Question 11

What happens when the diaphragm contracts?

Answer 11

The diaphragm will flatten/pull ribcage out
-pressure changes from this allows for increased airflow into the lungs

Question 12

What are the landmarks of the diaphragm?

Answer 12

-central tendon
-caval foramen
-esophageal hiatus
-aortic hiatus

Question 13

What is the central tendon of the diaphragm?

Answer 13

Connective tissue that is anchored in the middle of all of the muscle fibers of the diaphragm
(not attached/anchored to any kind of bone)

Question 14

What travels through the caval foramen in the diaphragm? What is unique about this opening from the others?

Answer 14

The IVC (inferior vena cava) will travel through this opening to get to the abdomen
**the caval foramen actually opens through the central tendon of the diaphragm
*most anterior opening

Question 15

What travels through the esophageal hiatus in the diaphragm?

Answer 15

The esophagus will travel through this opening to get to the abdomen
*middle opening

Question 16

What travels through the aortic hiatus in the diaphragm? What junction is this opening at?

Answer 16

The aorta will travel through this opening to get to the abdomen
*opening is at junction of vertebral column, connective tissue/diaphragmatic muscle will arch up and over the vertebral column to form this tunnel/opening
*most posterior opening

Question 17

What are the three regions of the diaphragm?

Answer 17

-sternal part
-costal part
-lumbar part

Question 18

What is the attachment point for the sternal region of the diaphragm?

Answer 18

along the sternum *most anterior

Question 19

What is the attachment point for the costal part of the diaphragm?

Answer 19

along the ribs *more lateral

Question 20

What are the attachment points for the lumbar part of the diaphragm?

Answer 20

along quadratus lumborum (posterior wall of the abdominal cavity) and psoas muscle *most posterior