Anatomy - Week 3 - Introduction To Thoracic Cavity Flashcards
What are the 3 intercostal muscles?
External intercostal Internal intercostal Innermost intercostal (Both the external and internal muscles are innervated by the intercostal nerves)
What are external intercostal muscles?
The external intercostal muscles are responsible for forced and quiet inhalation. They raise the ribs and expand the chest cavity.
What is the internal intercostal muscle?
They are responsible for forced exhalation. They depress the ribs and decrease space in the chest cavity.
What are the muscles involved in inhalation?
Sternochloidmastoid
Scalene (fixes first rib)
External intercostal
Diaphragm
What are the muscles involved in exhalation?
Internal intercostals External oblique Internal oblique Transversus abdominis Rectus abdominis
What is included in the neurovascular bundle?
Intercostal vein
Intercostal artery
Intercostal nerve
Where do intercostal nerves arise from?
They arise from the anterior rami of true thoracic spinal nerves from T1 to T11
The ventral ramus of thoracic nerve 12 is the subcostal nerve.
What are the branches of the intercostal nerve?
Collateral branch - runs parallel to the main nerve on the upper border of the rib below
Lateral cutaneous Branch- innervates skin on the side of the thoracic wall by dividing into anterior and posterior branches
Anterior cutaneous branch - is the terminal portion of the intercostal nerves and innervates the skin near the Midline of chest by dividing into medial and lateral branches
Muscular branches - to intercostal muscles
Where does the internal thoracic artery arise?
Arises from 1st part subclavian a. It descends lateral to the sternum. At the sixth intercostal space, it divides into superior epigastric and musculophrenic arteries.
What are dermatomes?
An area of skin innervated by sensory fibres Fromm a single spinal nerve.
What is the definition of the mediastinum?
Is the potential space between the lungs, posterior to the sternum, anterior to the vertebral column, and above the diaphragm
What are the subdivisions of mediastinum?
Superior mediastinum
Inferior mediastinum - anterior mediastinum, middle mediastinum, posterior mediastinum
What are the structures at the sternal angle?
The start and end of the aortic arch
The division between the superior and inferior mediatinum
The upper margin of the superior vena cava
The bifurcation of the pulmonary trunk
The level of the sternal angle
The level of rib 2 where it attaches to the sternum via the 2nd costal cartilage
The body of vertbrae t4
What are the boundaries of the superior mediastinum?
Ant - manubrium sterni
Post - T1 to T4
Sides - mediastinal pleura
Sup - plane of thoracic inlet
What are the contents of the superior mediastinum?
Thymus, right and left brachiocephalic veins, superior vena cava, arch of the aorta with its 3 large branches, trachea, oesophagus, phrenic nerve, vagus nerves, left recurrent laryngeal branch of vagus nerve, thoracic duct.
