8.3 Thoracic walls and diaphragm

Question 1

What is the pump handle movement?

Answer 1

The pump handle movements moves the ribs in a posterior to anterior motion, so the ribs move slightly forward.

Question 2

What is the bucket handle movement?

Answer 2

The bucket handle movement is the change in the lateral aspect of the ribs (the width of the ribs changes

Question 3

Where can the thorax can be changed at:

Answer 3

• Vertical dimension by movement of the diaphragm
• Anteroposterior (AP) dimension by movement of upper ribs
• Lateral (transverse) dimension by movement of middle ribs

Question 4

Where do the posterior intercostal arteries originate?

Answer 4

aorta

Question 5

Where do the anterior intercostal arteries originate?

Answer 5

internal thoracic

arteries

Question 6

Where do the intercostal nerves originate?

Answer 6

Origin from anterior rami of spinal nerves (T1 T11)

• Between internal and Intercostal nerve innermost intercostal muscles

Question 7

Which intercostal muscles are most active and describe it.

Answer 7

External intercostal muscles
• inferomedial: bottom part of the rib above attaches to superior part of the rib below
• anteriorly replaced by external intercostal membrane
• most active in inspiration

Question 8

Describe the internal intercostal muscles.

Answer 8

expiration-passive, follows pressure gradient
Intermediate layer-internal, perpendicular to external
no major role , fibre direction

Question 9

Describe the inner most intercostal muscles.

Answer 9

• discontinuous

Question 10

What is the role of the phrenic nerve?

Answer 10

motor innervation

sensory: phrenic & others (s for share)
motor: phrenic nerve only

Question 11

Describe the right diaphragm in relation to the left diaphragm

Answer 11

right dome is slightly higher than left bc of liver
pushes it right down higher
right dome-firmer attachment to lumbar region
right crus longer than the left crus
R 1-3 L1-2

Question 12

Describe the diaphragm

Answer 12

arises from the bottom of the thoracic cage, peripherally

Muscular part:

• has circumferenial origins
• inserts into the central tendon
• No bony attachments in the central tendon

Question 13

Describe the Thoracic apertures

Answer 13

Boundary of the Inferior Aperture:
Anterior: the xiphoid process and costal margin
Lateral: 11-12th pairs of ribs
Posterior: vertebra T12