02.1 Lower Respiratory Tract - Anatomy Flashcards
What are the true ribs and why are they true ribs?
1-7
Connected by costal cartilage to sternum
How are ribs 8-12 connected?
8-10 connected to costal cartilage above
11,12 are floating ribs with their ends free in the abdominal muscles
Which ribs are typical?
3-9
What are the features of a typical rib?
Shaft
Costal groove on inferior surface
Articulating process for the transverse process
Neck
Head
2 Articulate facets, for corresponding vertebrae and the one above
Why is rib 1 considered atypical?
Rib 1 is short, broad and the most curved
It has a single articular facet
Why is rib 2 considered atypical?
Poorly marked costal groove
Why are ribs 11-12 considered atypical?
Single facet
No tubercle
Floating
What are the three intercostal muscles in each intercostal space?
External
Internal
Innermost
What direction do the external intercostal muscle fibres run?
Inferiorly and anteriorly
What does contraction of the external intercostal muscles do?
Elevates the ribs.
Elevating upper ribs increases AP diameter.
Elevation of lower ribs increases lateral diameter.
What is the role of the internal and innermost intercostal muscles?
To depress the ribs during forced expiration.
Reduces AP and lateral diameters of the chest.
Where does each rib’s neurovascular bundle run?
In the costal groove of each rib
What nerves are in the neurovascular bundle, where do they run and what do they supply?
Anterior rami of thoracic spinal nerves, T1-T12
Between internal and innermost intercostal muscles
Supply the intercostal muscles, parietal pleura and overlying skin
What arteries supply the intercostal muscles?
Anterior and posterior intercostal arteries.
How many arteries are in each intercostal space?
1x posterior artery from the thoracic aorta
2x anterior artery from the internal thoracic artery
What is the venous drainage of the intercostal spaces?
Primarily into the azygos system.
Some drainage into the internal thoracic vein.
What makes up the azygos system?
Azygos vein - Right aide
Hemiazygos vein and accessory hemiazygos vein - Left side
What nerve supplies the diaphragm?
Phrenic nerve (C3,C4,C5)
At what level is the opening for the vena cava in the diaphragm?
T8
At what level is the opening for the oesophagus in the diaphragm?
T10
At what level is the opening for the aorta in the diaphragm?
T12
What is the level of the diaphragm domes during expiration?
Right - behind 5th rib MCL
Left - 5th ICS, MCL
What is the costodiaphragmatic recess?
The pleura lined gutters that the lungs don’t fill.
What are the borders of the trachea?
Lower border of cricoid cartilage to the carina
What are the most inferior points of the pleura in terms of body markings?
8th rib, mid clavicular line
10th rib, mid axillary line
12th rib, in the scapular line
What are the inferior limits of the lungs in terms of body markings?
6th rib MCL
8th rib Mid axillary line
10th rib Scapular line
Which bronchi is stuff more likely to get stuck in and why?
Right bronchi as it is shorter, wider and more vertical
What can an apical lung tumour involve?
Brachial plexus
Subclavian vessels
Sympathetic trunk
What structures can be found in the superior mediastinum?
Superior vena cava Brachiocephalic veins Arch of aorta Trachea Oesophagus Thoracic duct Thymus Vagus nerve Left recurrent laryngeal nerve Phrenic nerve
What can be found in the middle mediastinum?
Pericardium Heart Roots of the great vessels Azygos vein Main bronchi
What can be found in the posterior mediastinum?
Oesophagus Thoracic aorta Azygos and hemiazygos veins Sympathetic trunks Vagus nerve Splanchnic nerves
What are the three parts of the sternum?
Manubrium
Body
Xiphoid process
