Respiratory Session 2- Anatomy, Ventilation & Mechanics Of Breathing Flashcards
What are the 3 parts of the sternum and what do they articulate with?
Manubrium- 1st & part of 2nd costal cartilages
Body- part of 2nd & 3rd-7th costal cartilages
Xiphesternum
What is the sternal angle?
Junction of the manubrium and body- felt as a transverse ridge on palpating of sternum
How do the ribs articulate with the vertebral column posteriorly?
Costovertebral joints
How do the ribs articulate anteriorly?
Ribs 1-7 are connected to the sternum via costal cartilages
Ribs 8-10 articulate with costal cartilage above
Ribs 11-12 end free in abdominal muscles
Describe the 3 main features of a typical rib
Head- 2 articular facets for articulation with vertebra
Tubercle- 1 articular facet for articulation with transverse process of corresponding vertebra
Shaft- thin, flat and curved. Shaft has a costal groove close to its lower border to protect intercostal vessels and nerves
Describe the 2 synovial joints that connect the ribs with thoracic vertebrae
Joint of the rib head- head of rib articulates with body of corresponding vertebra and vertebra above
Cost transverse joint- articular facet on tubercle of rib articulates with transverse process of corresponding vertebra
Name the 3 intercostal muscles
External intercostal
Internal intercostal
Innermost intercostal
Describe the external intercostal muscles
Fibres run downwards and anteriorly from inferior margin of rib above to superior margin of rib below
What movement are the external intercostal responsible for?
Elevation of ribs in ‘bucket handle’ movement to increase anteroposterior and transverse diameters of the chest
Responsible for 30% of chest expansion in quiet respiration
Describe the internal intercostal muscles and how this relates to their function
Fibres run downwards and posteriorly form the rib above to rib below
Action pulls the ribs down from position of chest expansion
Active during forced expiration
Innermost assist with the movement
What are the contents of the neurovascular bundle from above to below?
Intercostal vein
Intercostal artery
Intercostal nerve
Where is the neurovascular bundle found?
In the intercostal groove of the rib, between internal and innermost intercostal muscles
What do the intercostal arteries supply?
Intercostal muscles
Parietal pleura
Overlying skin
Where does the anterior intercostal artery arise from?
Internal thoracic artery and its continuation, the musculophrenic artery
Where does the posterior intercostal artery arise from?
Aorta and intercostal artery
How many intercostal veins per space?
3
2 anterior and 1 posterior
Where do the intercostal veins drain into?
Anterior veins drain via internal thoracic vein into the subclavian vein
Posterior veins drain via azygos vein on the right and hemiazygos vein on the left into SVC
What are the nerve roots of the intercostal nerves and what do they supply?
Anterior rami of thoracic spinal nerves T1-T12
Supply intercostal muscles, parietal pleura and overlying skin
Describe the shape of the diaphragm and its anatomical position
Dome shaped muscle which divides thoracic cavity from the abdominal cavity. Right dome of the diaphragm lies at level of 5th rib and left dome at 5th intercostal space.
What 2 parts does the diaphragm consist of?
Peripheral muscular part
Central tendon
What are the attachment sites of the diaphragm?
Inner aspects of the xiphisternum
Inner aspects of the 7-12 costal cartilages
Arcuate ligaments
Crura of the diaphragm
Where are the openings in the diaphragm and what are they for?
T8- IVC
T10- Oesophagus
T12- Aorta
What is the innervation of the diaphragm and nerve roots?
Phrenic nerve
C3, 4, 5 (keep the diaphragm alive)
What parts does the thoracic cavity consist of?
2 lateral pulmonary cavities and the central mediastinum
What are the 4 compartments of the mediastinum?
Superior
Middle
Anterior
Posterior
What are the contents of the superior mediastinum?
Arch of aorta SVC Vagus nerve Phrenic nerve Thymus Trachea Thoracic duct Muscles Oesophagus
What are the contents of the middle mediastinum?
Heart Ascending aorta Pulmonary trunk SVC L&R phrenic nerves Cardiac plexus Tracheobronchial lymphnodes
What are the contents of the anterior mediastinum?
Loose connective tissue
What are the contents of the posterior mediastinum?
Oesophagus Descending aorta Thoracic duct Azygos system of veins Thoracic sympathetic trunks
Describe the pleura
Serous membrane consisting of a parietal and visceral layer
Visceral lines outside of lungs
Parietal lines inside of each hemithorax and is continuous at the hilum of the lung with visceral pleura
What is the pleural space and its fuction?
Potential space between the 2 layers of pleura lined with pleural fluid to allow the parietal and visceral pleura to slide on one another
What is the blood supply of the pleura?
Parietal- intercostal arteries and internal thoracic arteries
Visceral- bronchial arteries
What is the nerve supply of the pleura?
Parietal- somatic innervation from intercostal and phrenic nerves
Visceral- only autonomic innervation
What are the boundaries of the trachea?
Lower border of the cricoid cartilage and terminates by dividing into right and left main bronchi at sternal angle