Thoracic Wall 2

Question 1

Function of pectoralis major

Answer 1

Abducts and medially rotates humerus (flexion)

Question 2

Function of pectoralis minor

Answer 2

stabilises scapula

Question 3

Function of serratus anterior

Answer 3

holds scapula against thoracic wall

Question 4

How many pairs of intercostal spaces are there?

Answer 4

11

Question 5

Where are the external intercostal muscles located?

Answer 5

Extend from inferior edge of the rib above to the superior edge of the rib below

Question 6

Function of the external intercostal muscles

Answer 6

Raise ribs in inspiration

Question 7

Where are the external intercostal muscles replaced by membrane

Answer 7

Anteriorly (upper edge is closer to vertebral column

Question 8

Where are the internal intercostal muscles located?

Answer 8

Extend from lateral edge of rib above to superior edge of rib below

Question 9

Function of the internal intercostal muscles

Answer 9

Prevent indrawing; aid elastic recoil in expiration

Question 10

Where are internal intercostal muscles replaced by membrane?

Answer 10

Posteriorly (lower attachment is closer to vertebrae)

Question 11

Name 3 other muscles of the thoracic wall

Answer 11

Innermost intercostal muscle, transverus thoracis, subcostalis

Question 12

What passes through the intervertebral foramen?

Answer 12

spinal nerve

Question 13

What nerves don’t form a plexus?

Answer 13

Anterior rami of thoracic spinal nerve – maintain their segmental orientation

Question 14

Where do the intercostal nerve, artery and vein lie?

Answer 14

Costal groove at the inferior edge of the rib between the internal and innermost intercostal muscles

Question 15

What other nerves supply the anterior thoracic wall?

Answer 15

Supraclavicular (C3-4); descend over clavicle as far as the 2nd CC

Question 16

What thoracic nerve is at risk during breast surgery?

Answer 16

T2, intercostobrachial  supplies thorax wall in the axilla and upper, medial part of upper limb

Question 17

What does the ventral ramus of T1 supply?

Answer 17

Small muscles of the hand, skin if the medial aspect of the arm and forearm and muscles of the 1st intercostal space

Question 18

What does the ventral ramus of T2-T11 supply?

Answer 18

Motor fibres of intercostal muscles and abdominal muscles and sensory supply to the skin and parietal pleura

Question 19

What does the subclavian artery split into?

Answer 19

Vertebral artery (supplies CNS), thyrocervical trunk, costo-cervical trunk, internal thoracic artery

Question 20

What level is the thoracic aorta at?

Answer 20

T4-T12 (T4/5 = sternal angle)

Question 21

What does the thoracic aorta split into?

Answer 21

Posterior intercostal arteries (3rd-11th), subcostal artery and superior phrenic artery

Question 22

What does the internal thoracic artery split into?

Answer 22

Superior epigastric and musculophrenic arteries (anterior)

Question 23

Where do the 1st and 2nd intercostal arteries arise from?

Answer 23

Supreme intercostal branch of costo-cervical trunk

Question 24

Where do the anterior intercostal arteries arise from?

Answer 24

• Internal thoracic artery (1-6)

- 7-10 = branch from musculophrenic

Question 25

Where do the anterior intercostal veins drain to?

Answer 25

Internal thoracic vein –> brachiocephalic vein

Question 26

Where do the posterior intercostal veins drain to?

Answer 26

Brachiocephalic or superior vena cava via azygos system

Question 27

Where does the azygos system pass?

Answer 27

Behind diaphragm with the aorta and thoracic duct

Question 28

What does the azygos vein connect to

Answer 28

Superior and inferior vena cava

Question 29

Where does the hemiazygos vein cross to the right?

Answer 29

T9 to join azygos

Question 30

Where does the hemiazygos vein pass?

Answer 30

Through or behind left crus of diaphragm

Question 31

What does the accessory hemiazygos vein drain?

Answer 31

5-8 of left side

Question 32

Name the anterior lymph nodes of the thoracic wall

Answer 32

Parasternal node and broncho-mediastinal trunks

Question 33

Name the posterior lymph nodes if the thoracic wall

Answer 33

Intercostal nodes, thoracic duct (inferior) and broncho-mediastinal trunks (superior)

Question 34

What does the hemiazygos vein drain?

Answer 34

Left posterior intercostal veins of ribs 9-12