Thorax & Resp System (Exam 3) Flashcards
The ___ rib inserts at the Sternal Angle (Manubriosternal)
Second
At what level does the Second Rib insert at the Sternal Angle? A. T2-T3 B. T1-T2 C. T4-T5 D. T3-T4
C. T4-T5
The Sternal Angle separates the ___ from the Inferior Mediastinum
Superior
The Sternal Angle is at the level of Tracheal Bifurcation which is also the ___
Carina
The Sternal Angle is an important landmark for many other features and separates…
- Superior limit of Pericardium and of the Pulmonary Trunk
- Where Arch of the Aorta begins
- Where Superior Vena Cava begins to enter the RA - Central Venous Pressure determination
The top of the Manubrium (Suprasternal Notch) is at the level of?
T2-T3
The Mediastinum is divided into what 5 areas?
- Anterior
- Middle
- Posterior
- Superior
- Inferior
What are the 4 contents of the Anterior Mediastinum?
- Thymus (behind Manubrium)
- Internal Mammary vessels
- Lymph nodes
- Loose Connective Tissue
Think Ant “TILL”
What are the 5 main contents of the Middle Mediastinum?
- Pericardia (Fibrous, Serous [Visceral and Parietal])
- Heart
- Great Vessels (Aorta, SVC, IVC, Pulmonary aa and vv)
- Nerves (Vagus, sympathetics, Phrenics)
- Trachea
What are the 6 main contents of the Posterior Mediastinum?
- Descending Aorta
- Esophagus
- Intercostal aa and vv
- Thoracic Duct
- Azygos
- Hemiazygos vv
The Thoracic Duct carries ___ from below the diaphragm up into the ___ veins.
lymph
Subclavian
What are the 10 main contents of the Superior Mediastinum
- Thymus
- Brachiocephalic vv
- SVC
- Aortic Arch and Branches
- Trachea
- Esophagus
- Phrenic nn
- Vagus nn
- L Recurrent Laryngeal n
- Thoracic Duct
What is the significance of buffalo not having a mediastinum?
Having no mediastinum creates an open pneumothorax (air pressure is much higher outside) - air rushes in and the lungs collapse.
Both lungs will collapse at the same time due to no mediastinum
What is the significance of the cervical plexus?
C3, 4, 5 keep you alive
Phrenic nerves originate here
Diaphragm Innervation:
The Phrenic Nerves take a “___ ___” through the Middle Mediastinum
“Vascular route”
Diaphragm Innervation:
The R Phrenic follows the ___. The L Phrenic follow the ___ ___.
R follows Veins (SVC, RA, and IVC)
L follows Arterial blood (PA, LV)
*Phrenic Nerves take a Vascular Route through the Middle Mediastinum
The L Vagus takes the ___ route through the Superior Mediastinum, then takes the ___ route through the Posterior Mediastinum
arterial
food
The R Vagus takes the ___ route (next to Trachea) in the Superior Mediastinum then takes the ___ route in the Posterior Mediastinum
air
food
The Vagus nerve is located ____ to the phrenic nerve. In the Mediastinum it passes posterior to the ___ ___.
posterior
hilar roots
What happens in unilateral Phrenic Nerve paralysis?
The phrenic nerve provides the primary motor nerve to the diaphragm. Injury to either side of the diaphragm = loss of the ability to contract and allow proper inspiration.
This can impact daily living by causing dyspnea, sleep disturbances, or in severe cases decreased life expectancy.
Leading cause of unilateral paralysis is iatrogenic (from surgery…or trauma)
What innervates the diaphragm?
Phrenic nerve
Caput Medusae is a sign of what?
Portal hypertension
Caput Medusae is created by distension of the Superior and Inferior Epigastric veins and this extends into the ___ ___ ___
Thoraco-epigastric anastomosis (collaterals)
What are the Primary Muscles of breathing?
- Diaphragm (75% of inspiration, quiet respiration, Phrenic n (C3,4,5)
- External Intercostals (move ribs up and out - T1-T11 - “hands into pockets”)
- Interchondral portion of the Internal Intercostals (T1-T11 - at 90 degrees to external)