Ch 3-Thorax: Key features

Question 1

-T4 and T5

Answer 1

• Pass through sternal angle marking rib 2 as a reference
• separates superior mediastinum from inferior mediastinum (DIFFERENT FROM APETURES)
• Marks beginning and end of arch of aorta
• passes site of superior vena cava penetrates pericardium
• level of trachea bifurcates into right/left bronchi
• marks superior limit of pulm. Trunk

Question 2

-Venous shunts from left to right

Answer 2

• On the right side of body is, the right atrium, superior and inferior vena cava.
• Right atrium receives deoxygented blood, and vena cavas drain into it.
• Left brachiocephalic vein carries blood from left side → superior vena cava
• Hemizygos and Accessory hemizygos from left → Azygous vein (on right) → superior vena c

Question 3

Segmental neurovascular supply of thoracic wall

Answer 3

• Arteries to wall from:
  - Thoracic aorta in post mediastinum
  - Internal thoracic arteries each side of sternum
  
  • Post and ant intercostal vessels (with intercostal nerves) from these, pass laterally along inferior ribs
  • Anterosuperior region of trunk: from Anterior ramus of C4 via supraclavicular branches
  • Highest thoracic dermatome: T2
  • Midline: T6 over xyphoid process
  • T7 to T12 follow rib contour.

Question 4

Sympathetic

Answer 4

-Pregang nerve fibers carried out of spinal cord in spinal nerves T1 to L12.

Question 5

Flexible wall and inferior thoracic aperture

Answer 5

• Ribs post attachment is superior to ant attachment:
• When elevated, moves ant thoracic forward (Pump Handle). And inferior middle ribs move out laterally, extending thoracic wall (Bucket handle)

Question 6

-Innervation of diaphragm

Answer 6

• 2 Phrenic nerves coming from ant rami of cervical nerves C3, C4, and C5, on both sides.
  
  • Pass vertically through neck, sup thor aper, and mediastinum. Pass anteriorly to roots of lungs.
  • Tissue that gives rise to diaphragm originates superior to ultimate location of diaphragm.

Question 7

-Lungs-

Answer 7

• Pulmonary arteries: deoxygented to lungs from right ventricle.
• Pulmonary veins: oxygenated returns to left atrium v
• Right lung is big becoz of middle mediastinum with heart.
  
  • Base, apex,
  • 2 surfaces: Costal, Mediastinal
  • 3 borders: Inferior, Anterior, Posterior
  • Root attaches to lung
  • Hilum-covering/encasing of of root.
    
    • Pulmonary artery
    • 2 pulmonary veins
    • main bronchus
    • bronchial vessels
    • nerves
    • lymphatics
  • Pulmonary ligament-inferior to hilum.
  • Vagus nerve posterior, phrenic nerves anterior.

Question 8

Right lung

Answer 8

-3 lobes, 2 fissures
-oblique and horizontal fissures
-inferior, middle, superior lobes
The orientations of fissure determines where should listen for lung sounds from each lobe.

-Medial surface structures:
-Heart -Inferior/Superior vena c
-azygous vein
-esophagus
– Right subclavian artery/vein

Question 9

Left lung

Answer 9

• 2 lobes, 1 fissure
  - Oblique fissure
  
  • Superior, Inferior lobes
  • Anterior lower part of superior is lingula of left lung projects over heart bulge.
• Medial surface structures:
  
  • heart
    - aortic arch
    - thoracic aorta
    - esophagus
    - left subclavian artery/vein