Intercostal Spaces Flashcards
What are the three parts of the intercostal muscle?
- External intercostal muscle/Anterior intercostal membrane
- Internal intercostal
- Innermost intercostal
When does the external intercostal muscle turn into the anterior intercostal membrane?
At the sagittal level of the costochondral joint
What passes between the internal and innermost intercostal muscle?
- Intercostal vein
- Intercostal artery
- Intercostal nerve
What direction do external muscle fibres run?
Medial and down
What direction do internal and innermost muscle fibres run?
Lateral and down
With regards to respiration, what is the difference between external and internal intercostal muscles?
External intercostal muscles are responsible for forced and quiet inhalation, where internal intercostal muscles are responsible for forced exhalation
In what order does the neurovascular bundle run?
- Vein
- Artery
- Nerve
Where on the rib is the neurovascular bundle found?
Costal groove
What are 4 the branches of the intercostal nerve?
- Lateral Cutaneous Branch
- Small Collateral Branch
- Anterior Cutaneous Branch
- Muscular branches
Where do intercostal nerves arise from in T1 to T11?
Anterior rami of thoracic spinal nerves
What is the collateral branch of the intercostal nerve?
Runs parallel to the main nerve on the upper boarder of the rib below
What is the function of the lateral cutaneous branch of the intercostal nerve?
Innervates skin on the side of the thoracic wall
What is the function of the anterior cutaneous branch of the intercostal nerve?
Innervates skin near midline of chest
What is the muscular branch of the intercostal nerve?
Goes to intercostal muscles
Where does the internal thoracic artery arise from?
1st part of the subclavian artery
Where does the internal thoracic artery descend to?
Level of the 6th intercostal space
What happens to the internal thoracic artery at the level of the 6th intercostal space?
It bifurcates into superior epigastric and musculophrenic arteries
What is a dermatome?
An area of skin innervated by sensory fibres from a single spinal nerve
What is the mediastinum?
The potential space between lungs, posterior to sternum, anterior to vertebral column and above the diaphragm
What are the 2 sections of the mediastinum?
- Superior mediastinum
2. Inferior mediastinum
Where is the boundary of the superior and inferior mediastinum?
Level of the sternal angle
What are the 3 sections of the inferior mediastinum?
- Anterior mediastinum
- Middle mediastinum
- Posterior mediastinum
What are the 6 structures found at the sternal angle?
- Start and end of aortic arch
- Division between superior and inferior mediastinum
- Upper margin of superior vena cava
- Bifurcation of pulmonary trunk
- Rib 2 attaches to sternum
- Level of body of T4 vertebra
What are the 3 branches of the aorta?
- Brachiocephalic Trunk
- Left Common Carotid Artery
- Left Subclavian Artery
What divides inferior mediastinum into 3 sections?
Heart
What are 4 main features of the superior mediastinum?
- Aortic arch
- Trachea and Oesophagus
- Vagus nerves
- Thoracic duct
What are 2 main features of the anterior mediastinum?
- Mediastinal branches of internal thoracic vessels
2. Sternopericardial ligaments
What is the function of sternopericardial ligaments?
Attaches the heart to the sternum
What is the main feature of the middle mediastinum?
Heart
What are the 4 main features of the posterior mediastinum?
- Azygous and hemizygous veins
- Sympathetic chains
- Descending aorta
- Trachea and Oesophagus
Where is the thoracic duct found?
Left hand side of the azygous vein
At what level does the azygous vein drain into the superior vena cava?
Level of T4 vertebra
What is the anterior cutaneous branch of the intercostal nerve?
The terminal portion of the intercostal nerve
