Thorax 2

Question 1

Name 3 muscles that attach to the coracoid process

Answer 1

Pec minor, coracobrachialis and biceps brachii

Question 2

What muscles of the back are in the thorax

Answer 2

Serratus anterior, serratus posterior superior and inferior.

Question 3

Describe features of the external intercostal muscles

Answer 3

• Extend from rib above to superior edge of rib below.
• Anteriorly fibers are replaced by external intercostal membrane.
• Function is to raise ribs during inspiration

Question 4

Describe features of the internal intercostal muscles

Answer 4

• Extend from lat edge of costal groove to superior edge of rib below.
• Posteriorly fibres are replaced by internal intercostal membrane.
• Prevents indrawing during inspiration and aids eleatic recoil by moving ribs inferiorly

Question 5

Name the other minor muscles of the thorax

Answer 5

Innermost intercostal - though to act with internal intercostal. Deep surface is covered with endothoracic fascia.

• Transversus thoracis, lies posterior to sternum from ribs 3-6, weekly depresses ribs.
• Subcostalis - lies on pos wall, extending two/3 ribs below.

Question 6

Where does the spinal nerves pass out of?

Answer 6

The intervertebral foramenn, made up of the pedicle, articular processes, vertebral body and IV disc

Question 7

Describe how the spinal cord forms the intercostal nerves

Answer 7

The anterior rami of the thoracic spinal nerves maintain their segmental orientation and become intercostal nerves which then run in the costal groove with the intercostal vein and artery (VAN)

Question 8

Describe the cutaneous branches of the intercostal nerves

Answer 8

First gives off a lateral cutaneous branch and then becomes superficial parasternally now being called the anterior cutaneous branch

Question 9

What is the anterior thoracic wall supplied by?

Answer 9

Intercostal nerves and the supraclavicular nerve (only supplies the skin as far down as 2nd costal cartilage)

Question 10

What is the cutaneous branch of T2 called and where does it supply?

Answer 10

The intercostobrachial nerve and it supplies the thorax wall in the axilla and upper medial part of upper limb. At risk during breast surgery.

Question 11

What does the ventral rami of T2-T11 do?

Answer 11

Provide motor fibres to intercostal muscles and abdo muscles and sensory supply to the skin and parietal pleura

Question 12

Describe the arterial supply of the thoracic wall

Answer 12

The subclavian artery gives off major branches; costocervial trunk and internal thoracic.
- The thoracic aorta gives off 3-11 posterior intercostal arteries, subcostal a. and superior phrenic a.

Question 13

Describe the supply of the 10 anterior intercostal arteries

Answer 13

The internal thoracic artery supplies the first 6 anterior intercostal. The 7th to 10th IC arteries are branches off the musculophrenic artery

Question 14

Describe the supply of the 11 posterior intercostal arteries

Answer 14

the 1st and 2nd intercostal arteries are supplied by the supreme intercostal a. which is a branch off the costo-cervical trunk. The 3rd to 11th IC arteries are supplied by the thoracic aorta

Question 15

Briefly describe the venous drainage of the anterior intercostal veins

Answer 15

They drain to the internal thoracic vein and then to the brachiocephalic vein

Question 16

Describe the drainage of the right (R) posterior intercostal (IC) veins

Answer 16

1st IC vein (supreme IC vein) - R brachiocephalic vein

2/3/4 IC veins drain to R superior intercostal vein and then to Azygos.

5/6/7/8/9/10/11 IC veins drain to Azygos.

Question 17

Describe the drainage of the Left (L) intercostal (IC) veins

Answer 17

1st IC vein - L brachiocephalic vein

2/3/4th IC vein drains to L superior intercostal vein then to L brachiocephalic vein.

5-8th IC vein drains to accessory hemiazygos then to azygos.

9-11th IC vein drains to hemiazygos then to azygos.

Question 18

Describe features of the Azygos system, the function and the origin

Answer 18

Drains posterior wall of thorax and parts of posterior abdo wall.
It begins from the lumbar vein and passes behind the diaphragm and opens into the SVC. it conndects the SVC and the IVC

Question 19

Describe features of the hemiazygoz

Answer 19

It has connections with the left renal vein and crosses to the right at T9 to join azygoz.

Question 20

Describe features of the accessory hemiazygos

Answer 20

decends from 4th intercostal space and crosses at T8. It can open into Azygos, Hemiazygos or both.

Question 21

Describe the lymphatic drainage of the anterior thoracic wall

Answer 21

Anteriorly lymph drains to parasternal nodes and the bronchomediastinal trunk.

Question 22

Describe the lymphatic drainage of the posterior thoracic wall

Answer 22

Lymph drains to intercostal nodes and inferiorly to thoracic duct or superiorly to the bronchomediastinal trunk.