Thorax

Question 1

Boundaries of the thorax(superior, inferior, lateral, anterior, and posterior)

Answer 1

Superior;
- 1st rib
- 1st vertebrae
- manubrium

Inferior
- 11th/12th rib
- 12th thoracic vertebra
- xiphoid process
- subcostal arch
- diaphragm

Anterior
- sternum
- ribs
- intercostals

Lateral
- ribs
- intercostals

Posterior
- Vertebrae(&discs)
- Ribs
- intercostals

Question 2

Posterior thoracic wall joints

Answer 2

Interbody joints
- between the vertebrae
- cartilaginous joints

Costovertebral
- rib to vertebrae
- synovial

Costotransverse
- rib to transverse process of vertebrae
- synovial
- (costotransverse ligament also attaches to the superior transverse process)

Question 3

Anterior Thorax Joints

Answer 3

Sternocostal(sternochondral)
- sternum to cartilage
- synovial

Costochondral
- ribs(1-10) to cartilage
- cartilaginous

Interchondral
- ribs 6-10 attached to each other
- synovial

Question 4

Intercostal ‘space’, Innervation & vasculature

Answer 4

Intercostal nerves
- follow BV
- feed into the ventral ramus of spinal nerves
- supply intercostal muscles, skin, and parietal pleura.

Anterior intercostal artery
(subclavian artery –> internal thoracic artery –> anterior intercostal artery

Posterior intercostal artery
- thoracic aorta –> posterior intercostal artery

Anterior intercostal vein
–> internal thoracic vein –> brachiocephalic vein

Posterior intercostal vein
–> azygous system

Question 5

Azygous system

Question 5

Surgical approaches to the thoracic cavity;

Answer 5

Intercostal space
- intercostal muscles
- “thoracotomy”
- skin, superficial & deep fascia, & intercostals.
- Pro: less effect on overall structures.
- con: higher risk to damaging BV and nerves, need to be careful about depth, or the pleural cavity can be damages

Rib Bed
- rib transection
- “Costal resection”
- con: risk compromising the bony stability of the thoracic cage.

Sternum
- sternal transection
- “sternocotomy”
- split the body of the sternum inferior to the manubrium (leave some complete bone)
- risk of many BVs in that area, and damaging pleura and or/pericardium.
- often need wires to reinforce the sternum to hold itself together afterward.

Question 5

Subdivisions of the mediastinum

Answer 5

• sternum –> vertebral column
• sternal angle –>T4

Anterior;
- sternum–> pericardium
medial
- pericardium
posterior
- pericardium–>vertebrae

Question 5

Superior & inferior mediastinum

Answer 5

Superior mediastinum
- below the 1st vertebrae, 1st rib, and manubrium
- above the line continuing from the sternal angle to the interbody disc below T4 vertebrae.

Inferior mediastinum
- below the line
- above the diaphragm, subcostal arch, 11&12 rib and 12th vertebrae

Question 5

Anterior, middle, and posterior mediastinum

Answer 5

Anterior mediastinum
- posterior to the sternum
- anterior to the pericardium.

Middle mediastinum
- the pericardial part.

Posterior mediastinum
- posterior to the pericardium,
- anterior to the vertebrae.

Question 6

Anatomical structures of the superior mediastinum

Answer 6

• thymus, thoracic duct
• internal thoracic blood vessels, greatblood vessels of the heart, ligamentum arteriousum, axygous vein
• vagus n., phernic n., recurrent laryngeal n., sympathetic trunk
• trachea
• oesophagus

Question 7

Anatomical structures of the inferior mediastinum
(Anterior, middle, posterior)

Answer 7

Anterior
- lymph nodes
- vessels

Middle
- pericardium & heart

Posterior
- oesophaugs
- vagus nerve
- thoracic aorta