Anatomy of the thorax Flashcards
What does the thorax contain?
Lungs heart oesophagus trachea major vessels e.g. aorta
What is the thoracic wall made up of?
12 pairs of ribs costal cartilages sternum nerves and arteries that supply it intercostal muscles thoracic vertebrae
What is the sternum made up of?
Manubrium
Body
Xiphoid process
What are the true ribs?
Ribs 1-7
Their cartilage is directly attached to the sternum
what are the false ribs?
ribs 8-10
their cartilage attaches to the cartilage above, rather than directly to the sternum
what are the floating ribs?
ribs 11 and 12
they don’t attach to the sternum at all
What is the superior thoracic aperture?
region just above the first rib, it is a thoracic opening.
What does inferior thoracic aperture do?
it connects the thorax with the abdomen
what attaches at the inferior thoracic aperture?
diaphragm
what is the diaphragm, what is is the principal muscle for and where does it project upto?
a dome shaped, sheet of muscle which is the principal muscle of respiration. it extends up to the level of the 5th rib
What are the attachments of the diaphragm?
Attachments:
• Inferior 6 costal cartilages and adjacent ribs
• Xiphoid process
• L1-L3 vertebrae (extends down to attach to top 3 lumbar vertebrae)
What is the nerve supply of the diaphragm
Nerve supply:
• Phrenic nerve (C3-C5)
C3,4 ,5 – Keep the diaphragm alive !!!
what is an aperture?
an opening to allow vessels to pass through
What are three diaphragmatic apertures?
Caval opening (IVC)
Oesophageal hiatus
Aortic hiatus
What drains through each diaphragmatic aperture and at what level
Caval: IVC at T8
Oesophagus: Oesophagus at T10
Aortic: Aorta at T12
I 8 10 E (American spelling) A 12!!!
List the apertures form anterior to posterior
Caval/IVC (MOST ANTERIOR)
oesophagus
aorta
What are the 3 intercostal muscle layers?
Three layers: external, internal, innermost
what direction do external muscle fibres run in? What direction do they pull on the ribs?
They run from outwards to inwards and downwards. They lift the ribs below it. (inspiration)
what direction do internal muscle fibres run in? What direction do they pull on the ribs?
they run downwards and outwards. they pull the above rib downwards.
Where is the innermost muscle layer?
Deep to the inner muscle layer, it forms an incomplete layer
Where does the neurovascular bindle lie?
between the internal and innermost layers
what are the primary muscles of inhalation?
diaphragm
external intercostal
what are the accessory muscles of inhalation for when it is active? (4)
sternocleidomastoid
pectoralis minor
scalene
serratus anterior
what are the accessory muscles of exhalation for when it is active? (5)
internal oblique external oblique rectus abdominus transversus thoracis internal intercostal
From superior to inferior what is the order of the NV bundle? What is most exposed/least protected?
Vein
Artery
Nerve
(VAN)
The nerve is most exposed.
What does the Posterior intercostal artery originate from ?
Aorta
What does the Anterior intercostal artery originate from ?
Internal thoracic artery
Where does the internal thoracic artery run?
On either side of the sternum
Where does the internal thoracic artery originate from?
subclavian artery
What does internal thoracic artery bifurcate into?
Superior epigastric
musculophrenic artery
if the proximal aorta is restricted how can blood flow be maintained.
Subclavian – internal thoracic – anterior intercostal - posterior intercostal – aorta
What are the divisions of the thoracic cavity?
Left and right pulmonary cavity
mediastinum
What is the main organ in the mediastinum?
What are some of the other organs?
Heart
Trachea, oesophagus, thoracic duct, lymph nodes, phrenic and cardiac veins
what are the two pleurae of the lungs and which one is outer?
Parietal (outer)
Visceral
both continuous with one another
what are pleural recesses ?
These are potential spaces between the costal and diaphragmatic pleura that the lungs can move into during inspiration.
What is thoracentesis and where is the best lace for it?
Thoracentesis is a procedure to remove fluid or air from around the lungs.
Superior to rib to avoid NV bundle.
