Thoracic Cavity Flashcards
What major organs and tissues are contained within the thoracic cavity?
Heart Lungs Major blood vessels Part of the trachea Oesophagus
What is the thoracic wall comprised of?
Sternum
Thoracic vertebrae
Twelve pairs of ribs and costal cartilages
Intercostal muscles
What are the three parts of the sternum?
Manubrium
Body
Xiphoid process
At what age does the xiphoid process ossify?
40 years
Which ribs are the true ribs?
1-7
Which ribs are the false ribs?
8-10
Which ribs are the floating ribs?
11 and 12
What is the direction of fibres of the three intercostal muscles?
External intercostals run anteriorly and inferiorly and medially
Internal intercostals run anteriorly and laterally
Innermost intercostals have the same fibre direction as the internal intercostals
Where do the arteries, veins and nerves which supply the intercostal muscles exist?
Immediately inferior to the rib between the internal and innermost intercostal muscle layer
Which nerves supply the intercostal muscles?
The anterior rami of T1-11 spinal nerves form the intercostal nerves and the anterior rami of the T12 spinal nerve forms the subcostal nerve
What is the origin of the posterior intercostal artery?
Aorta
What is the origin of the anterior intercostal artery?
Internal thoracic artery
Which veins drain the anterior and posterior intercostal Arteries?
The azygous vein drains the posterior intercostal artery
The internal thoracic vein drains the anterior intercostal artery
Which rib surrounds the superior thoracic aperture?
Rib 1
Which muscle separates the thoracic and abdominal cavities?
Diaphragm
What nerve innervates the diaphragm?
Phrenic nerve
Where do the three apertures of the diaphragm exist and what structures travel through these apertures?
Inferior vena cava passes through diaphrgam at level of T8
Oesophagus travels through the diaphragm at the level of T10
Aorta pierces the diaphragm at the level of T12
From which artery does the internal thoracic artery originate?
Subclavian artery
What arteries does the internal thoracic artery bifurcate into?
Musculophrenic artery and superior epigastric artery
What is pectus excavatum?
A pectus deformity where the chest is hollowed in the centre
What is pectus carnium?
A pectus deformity where the chest sticks outwards
How can pectus deformities be treated?
With a Nuss bar
The sternal angle is a useful surface landmark which corresponds to the level of which costal cartilage?
Second
Between which two points is the transverse thoracic plane drawn?
Sternal angle and T4 vertebrae
The transverse thoracic plane indicates the boundary between the superior and inferior mediastinum and passes through which structures?
Carina
Superior limit of pericardium
Start and end of aortic arch
Superior vena cava
What parts of the vertebrae does the head of the typical rib articulate with?
The superior demi facet if the corresponding vertebra and the inferior demi facet of the vertebra superior to it
What part of the rib articulates with the transverse process of the corresponding vertebra?
The tubercle
How does the first rib differ in its articulations with the vertebrae?
It only articulates with T1
How do the tenth to twelfth ribs differ in its articulations with the vertebrae?
They only articulate with their corresponding vertebrae
How do the eleventh and twelfth ribs differ in its articulations with the vertebrae?
They only articulate with their corresponding vertebrae and they do not articulate with the transverse processes
The intraarticular ligament in the crest on the head of the rib attaches to which structure to hold the articulation steady?
Intervertebral disc
What structures does the diaphragm attach to?
L1-3
Inferior 6 costal cartilages and adjacent ribs
Xiphoid process
How far does the diaphragm move in quiet breathing as opposed to forced breathing?
Quiet 1-2cm
Forced 6-10cm
What is paradoxical breathing?
It is when the ribs move inwards during inspiration. And outwards during expiration which greatly reduces the ability of the thoracic cavity to expand during inspiration
Where does the azygous vein originate and where does it drain to?
It originates from the IVC and drains into the SVC
What is a hiatus hernia?
A protrusion of the stomach through the oesophageal hiatus
How is a congenital diaphragmatic hernia distinct from a hiatus hernia?
A congenital diaphragmatic hernia is a congenital malformation of the diaphragm and differs from a hiatus hernia where the stomach is pushed through an already existing opening
Where in the thorax does the sympathetic chain exist?
The posterior thoracic wall, lateral to the vertebral bodies
Where dies the thoracic duct originate?
In The abdomen as the cisterna chyli
In which aperture of the diaphragm does the cisterna chylii traverse to become the thoracic duct?
Aortic aperture
Where does the thoracic duct drain?
The venous angle of the left subclavian and internal jugular veins
