Exam 2 - Thorax & Mediastium

Question 1

Major blood vessels of trunk

Answer 1

• Aorta
• Carotid (head)
• Vena Cava
• Femoral Arteries/Veins
• Jugular Veins

Question 2

Femoral Artery location

Answer 2

• Just lateral to femoral vein

- Femoral vein is more medial

Question 3

Thorax consists of:

Answer 3

• Thoracic vertebrae (posterior)
• Ribs (lateral)
• Sternum (anterior)
• Costal cartilage (anterior)

Question 4

Purpose of Thorax

Answer 4

• Protective cage around vital organs
• Supports shoulder girdle and arms (upper limps)
• Lever mechanism for breathing muscles

Question 5

Major landmarks of Thorax

Answer 5

• Clavicles
• Sternum (Manubrium, Jugular notch, Sternal Body, Xiphoid process, Sternal Angle
• Costal Margins
• Midsternal line
• Midclavicular lines (two of them that cut each clavicle in half vertically)

Question 6

Manubrium

Answer 6

• Top portion of Sternum
• Jugular notch (Superior and at T2 level)
• Sternoclavicular joints (only attachment of upper limb to axial skeleton)

Question 7

Sternal Angle

Answer 7

• Junction between Manubrium and Sternal Body
• Marks:
  - Start/end of aortic arch
  - Trachea split into L and R primary bronchi
  - Azygos vein passes over to SVC

Question 8

Mini-sternotomy

Answer 8

• Surgeon only cuts top portion of sternum to expose aortic valve
• Patient has less recovery time and less pain
• Less visibility

Question 9

3 Types of Ribs

Answer 9

• True ribs: 1-7 / Attach directly to sternum
• False ribs: 8-12 / Attach indirectly or not at all
• Floating ribs: 11-12 / No attachment to sternum at all

Question 10

Costal groove

Answer 10

• Small groove in intercostal space where nerves and vessels run
• VAN (vein / artery / nerve –> from superior to inferior)
• VAN run through superior portion of intercostal space

Question 11

Two important nerves in Thorax

Answer 11

• Vagus: innervates heart and diaphragm

- Phrenic: innervates heart and diaphragm / controls breathing

Question 12

Intercostal nerves

Answer 12

• Derived from first 11 thoracic spinal nerves

- Give rise to sensory and motor branches

Question 13

Internal Thoracic Artery (Internal Mammory Artery)

Answer 13

• Very important artery
• Branches from subclavian artery
• One on each side of heart running down
• Used as conduit for CABG procedures (usually LEFT side)

Question 14

Anterior Intercostal Artery

Answer 14

• Arises from ITA
• Perfuses anterior portion of thoracic cavity
• Continuous with Posterior Intercostal Artery

Question 15

Posterior Intercostal Artery

Answer 15

• Arises from Thoracic Aorta

- Connects around to ITA in the anterior region

Question 16

Internal Thoracic Vein

Answer 16

• ITV
• Runs parallel to ITA along the ribs
• Drains into brachiocephalic vein

Question 17

Anterior Intercostal Vein

Answer 17

• Parallel to Anterior Intercostal Artery in intercostal space
• Drains into ITV & muscularphrenic vein -> brachiocephalic vein

Question 18

Posterior Intercostal Vein

Answer 18

• Runs parallel with posterior intercostal artery
• Upper 2 drain into brachiocephalic vein
• Lower 9 are part of Azygos system and drain into SCV

Question 19

Azygos System

Answer 19

• Collects blood from Thoracic Walls and Visceral Structures
  (Lungs / esophagus / thymus)
• Drains into SVC and has NO valves
  (Pressure dependent only –> good for blood storage)

Question 20

Veins of Azygos System

Answer 20

• Azygos Vein
• Posterior Intercostal Veins
• Hemi-Azygos vein
• Accessory hemi -Azygos vein

Question 21

Auscultation Points
(Listening to valves)

Answer 21

• Aortic (right 2nd ICS)
• Pulmonic (left 2nd ICS)
• Tricuspid (lower left Sternal border)
• Mitral (left 5th ICS at mid-clavicle line)

Question 22

Ectopic cordis

Answer 22

• Congenital defect where heart lies outside of sternum externally

Question 23

Pectus excavatum

Answer 23

• Inward funneling of the sternum

Question 24

Flail Chest

Answer 24

• Trauma resulting multiple rib fractures

- Chest wall will move freely with respiration

Question 25

Median Sternotomy

Answer 25

• Sternum split down the midline and retracted for surgical exposure of the heart or mediastinum

Question 26

Mediastinum contains:

Answer 26

• Heart
• Great vessels (SVC, Aorta, Pulmonary artery, etc.)
• Trachea
• Esophagus
• All thoracic organs (except lungs)

Question 27

Mediastinum Regions

Answer 27

• Superior (separated via the Sternal angle to the T4/T5 line)
• Inferior
  - Anterior (ITA, Inferior Thymus, Lymph nodes)
  - Middle (pericardial sac, heart)
  - Posterior (descending thoracic aorta, Azygos system, esophagus, vagus nerve, trachea, lymph nodes)

Question 28

Pericardium

Answer 28

• Confines heart to mediastium but allows for movement
• 2 layers: 5 to 10 cc between
  - Fibrous (superficial, tough, inelastic, protection)
  - Serous (form double layer around heart…parietal/visceral)
  - Visceral - aka epicardium
  - Parietal - fused to fibrous pericardium