The Thoracic cage, lungs and pleural cavities Flashcards
How are the true ribs connected to the sternum?
By Costal Cartilages
How many true ribs are there?
Seven pairs of true ribs
How do the false ribs attach to the rib cage?
The costal cartilages of ribs 8-10 fuse together and merge with the cartilages of rib pair 7
where are the origins of the external intercoastal muscles?
Inferior border of each rib
Where are the insertions of the external intercoastal muscles?
superior border of the rib below
What is the action of the external intercostal muscles?
elevate ribs (increase thoracic volume)
What is the innervation of the external and internal intercostal muscles?
intercostal nerves T1-T11
How many external intercostal muscles are there?
11 pairs
what is the origin of the internal intercostal muscles?
superior border of each rib
what is the insertion of the internal intercostal muscles?
inferior border of the preceding rib
What is the action of the internal intercostal muscles?
Depress Ribs
What is the third type of intercostal muscle called?
deeper internal intercostal muscle
What part of the nervous system are the intercostal nerves a part of?
somatic nervous system
What is the somatic nervous system?
it is part of the peripheral nervous system associated with the voluntary control of body movements via skeletal muscles
The Intercostal nerves are the anterior divisions of which spinal nerves?
The first 11 thoracic spinal nerves
where does the 1st intercostal nerve join to?
brachial plexus
what do the first six intercostal nerves innervate (in relation to intercostal space)?
skin, parietal pleura, intercostal muscle, serratus posterior muscle
what do the seventh to eleventh intercostal nerves innervate (in relation to intercostal space)?
skin, pariteal peritoneum, anterior abdominal muscles including: external oblique, internal oblique, transversus abdominus, rectus abdominus
What is the blood supply of the intercostal muscles?
Internal Thoracic artery- they descend lateral to the sternum on either side behind the costal cartilages
What is the internal thoracic artery a branch of?
The Subclavian Artery
What branches does the internal thoracic artery give off?
Anterior and Posterior Intercostal arteries
how many branches of the anterior intercostal artery are there?
12 branches (12 pairs of ribs)
Each intercostal space contains what arteries?
1 posterior and 2 anterior intercostal arteries
What does the thoracic cavity contain?
The lungs and heart; associated organs of the respiratory, cardovascular and lymphatic systems. Also contains the inferior portions of the oesophagus and thymus
What does the Thoracic cavity divide into?
Mediastinum, left and right pleural cavity
the right and left pleural cavities surround the right and left lungs, what does the Mediastinum contain?
Trachea, Oesophagus and other major vessels. It extend from the sternum anteriorly to the vertebrae posteriorly.
What is the pleura and what does it do?
shiny, slippery serous membrane which reduces friction as the lung expands and recoils during breathing
What is the pleura divided into?
the visceral and parietal pleura
What does the parietal pleura cover?
covers the mediastinal surface and the inner body wall
What does the visceral pleura cover?
covers the outer surface of the lung, extends into the fissure between the lobes
What is Mediastinum?
A membranous partition between two body cavities or two parts of an organ
What are the lungs suspended from the mediastinum by?
The lung root
What does the Hilum of each lung contain?
bronchus, 2 pulmonary veins and a pulmonary artery
The lung is connected to the mediastinum by one structure, what is it?
Hilum
How many lobes does the right lung have?
three
how many lobes does the left lung have?
two
Describe the lobes and fissures of the right lung
superior, middle and inferior lobe. With an oblique and horizontal fissure, the horizontal fissure divides the superior and middle lobe whilst the oblique fissure divides the inferior lobe from the superior and middle lobe.
Describe the lobes and fissure of the left lung
superior and inferior lobe. with an oblique fissure. The left lung also has a cardiac notch to accommodate the pericardial cavity.
where is the surface landmark for the apex of the lung?
in the neck 3cm above the medial third of the clavicle
Where are the parietal and visceral pleura connected?
The hilum of the lung
What is the bronchus?
passageway leading into the lungs, conducts air into the lungs.
Where does the trachea divide into the right and left bronchus?
tracheal bifurcation, at the level of the sternal angle and the fifth thoracic vertebra
what are the main differences between the right and left bronchus?
The right bronchus is more vertical, wider and shorter (food is more likely to get stuck down it). The left is smaller and longer in length. The right main bronchus enters the right lung at the level of the 5th thoracic vertebra whereas the left enters the lung at the sixth thoracic vertebra.
What are the three surfaces of the lungs?
Costal surface, mediastinal surface, diaphragmatic surface
What is the diaphragm?
skeletal muscle which separates the thoracic and abdominal cavities. Contracts to enlarge the thoracic cavity snf decrease pressure when breathing
What is the innervation of the diaphragm?
CIII, CIIII, CV keeps the diaphragm alive! the phrenic nerve.
what other effects does the diaphragm have apart from enlarging the thoracic cavity?
if the glottis is open air is drawn into the lungs.
Blood is drawn from the inferior vena cava into the right atrium
Where is the lower extent of the lung (surface anatomy)?
6th rib anteriorly, 8th rib mid-axillary line, 10th rib posteriorly
What is ‘intercostal recession’?
in patients with extreme breathlessness they may need to use accessory muscles to generate much lower pressure within the thorax during inspiration and much higher pressure on expiration. There pressures can sometimes overcome the intercostal muscles which causes the intercostal spaces to suck in during inspiration- this is intercostal recession and is an important sign of respiratory distress.
where are the oblique fissures (surface landmarks)?
sixth rib, mid-clavicular line
where is the horizontal fissure of the right lung (surface landmarks)?
fourth costal cartilage to rib five mid-axillary line
where are the superior lobes (surface landmarks)?
Anterior: 2nd intercostal space mid clavicular line
Posterior: Between C7 and T3
Where are the inferior lobes (surface landmarks)?
Anterior: 6th intercostal space mid-axillary line
Posterior: between T3 and T10
Where is the middle lobe (surface landmark)?
4th intercostal space mid-clavicular line
