Thoracic Wall And Respiration DLA

Question 1

What are the inferior thoracic aperture boundaries?

Answer 1

• 12th thoracic vertebra
• 11th and 12th pair of ribs
• Costalcartilages of ribs 7th - 10th (costal margin)
• Xiphisternal joint
• Closed by the diaphragm

Question 2

What are the muscles of inspiration?

Answer 2

Accessory:
Sternocleidomastoid (elevates sternum)

Scalenes 
  -anterior
  -middle
  -posterior 
(Elevates and fox upper ribs)

Principal:
External intercostals (elevates ribs, thus increasing width of thoracic cavity)

Interchondral part of internal intercostals (also elevates ribs)

Diaphragm (domes descend , thus increasing vertical dimension of thoracic cavity: also elevates lower ribs)

Question 3

What are the muscles of expiration?

Answer 3

Quiet breathing:
-Expiration results from passive recoil of lungs and rib cage

Active breathing:
-Internal intercostals, except interchondrial part

Abdominals (depress lower ribs, compress abdominal contents, 5hus pushing up diaphragm)

Include: 
Rectus Abdominis 
External oblique
Internal oblique
Transverse Abdominis.

Question 4

Summarize rib movement during respiration

Answer 4

“Pump handle” increases anterior-posterior (AP) dimensions

“bucket handle” increases lateral dimension.

Contraction of diaphragm increases vertical dimension

Question 5

What is the thoracic cavity?

Answer 5

Contains pleural cavities on either side of mediastinum

Question 6

What are the pleural cavities?

Answer 6

Lined by pleura- a double layer serous membrane (parietal and visceral) which surrounds the lung.

The two layers of the pleura meet at the root of the lung- mediastinal pleura meets visceral pleura

Question 7

Where does the neurovascular bundle travel?

Answer 7

Travels in costal groove on inferior aspect of rib all incisions/tubes placed above rib to avoid VAN

Question 8

What is thoracocentesis?

Answer 8

“Pleural trap” to sample fluid from pleural space

Question 9

What is thoracostomy?

Answer 9

Chest tube inserted to drain fluid or air from pleural cavity

Question 10

What arteries supply the parietal pleura?

Answer 10

Supplied segmentally by the vessels associated with the adjacent wall

Diaphragmatic is supplied by superior phrenic arteries

Mediastinal portion is supplied by pericardiophrenic artery

Question 11

What does the Costcocervical trunk supply?

Answer 11

Supplied the first 2 posterior intercostal spaces

Question 12

What does the Subclavian artery supply?

Answer 12

Gives internal thoracic artery

Vertebral artery

Costcocervical trunk

Question 13

What does the descending thoracic artery supply?

Answer 13

Supplied posterior intercostal arteries

Question 14

What does the posterior intercostal artery supply?

Answer 14

Runs in costal groove

Question 15

What does internal thoracic artery supply?

Answer 15

Gives anterior intercostalarteries and terminates into musculophrenic and superior epigastric

Question 16

What does the anterior intercostal artery supply?

Answer 16

Follows the inferior border of the rib and anastomoses with the posterior intercostal arteries

Question 17

What dies the musculophrenic artery supply?

Answer 17

Continues along the costal margin supplies diaphragm, anterior and lateral walls

Question 18

What does the superior epigastric artery supply?

Answer 18

Continues onto the anterior abdominal wall and anastomoses with inferior epigastric artery

Question 19

What veins drain the thoracic wall?

Answer 19

The veins from the upper 2 intercostal spaces Posteriorly join together and may drain into the azygos and accessory hemiazygos or directly into the brachiocephalic vein

Question 20

Describe lymphatic drainage of the thoracic wall

Answer 20

Drainage:
-Anteriorly to parasternal nodes

• Posteriorly to intercostal nodes
• Inferiorly to diaphragmatic nodes

Most lymph nodes from thorax eventually drain into thoracic duct
Upper part of right thorax into right bronchomediastinal trunk