chest and lungs Flashcards
what are 5 features of a rib?
head = end of a rib, where it connects to thoracic vertebrae, has two articular facets to connect with vertebrae above and of same number
neck = between head and body, has the tubercle
tubercle = a nub for the articulation to transverse process of vertebrae
body = shaft/main bit
costal groove = houses neurovascular bundle, between inner and innermost int. cost. muscles
what are the true ribs?
ribs 1 to 7 as their costal cartilage attaches directly to the sternum in the anterior
they also articulate posteriorly with the vertebrae
what are false tibs?
ribs 8-10
attach indirectly to the sternum, they attach to costal cartilage of rib above them
What are floating ribs?
don’t articulate to the sternum, only articulate posteriorly to the vertebrae, the ends are found free in the abdominal wall connected to their costal cartilage
what are the typical ribs?
ribs 3-9
typical head with two costal facets, include a neck, and have all the other stuff
which ribs are irregular and how so?
1st rib = shorter and fatter and only has one articular facet as there is no above thoracic vertebrae
2nd rib = long and thin and has a notch on its superior surface to connect to the serratus anterior
10th rib = only one facet to connect to corresponding vertebrae
11th and 12th rib = no neck and only one facet for articulation with their corresponding vertebrae
articulations of the rib?
Posterior - each rib articulates with the two vertebrae, the one above it in number, just once, and the vertebrae of the same number twice
Costotransverse joint - between tubercle of the rib and the transverse costal facet of the same number vertebrae
Costovertebral joint - between head of rib, superior costal facet of same number vertebrae and the inferior costal facet of the vertebrae above
The vertebral articular facets are where two vertebrae articulate. There will be one pair of facets on the superior side of the vertebrae and one pair on the inferior side of the vertebrae
define the thorax
bit of body between the neck and abdomen, housing and protecting the thoracic viscera responsible for respiration and circulation
consists of thoracic cage and thoracic cavity
what is the thoracic cavity bound by?
thoracic cage
superior thoracic aperture and inferior thoracic aperture
has cardiovascular and respiratory structures, nerves oesophagus and lymph nodes
what is the neurovascular bundle?
found in the costal groove, from top to bottom its VAN (vein, artery and nerve, making the nerve slightly exposed)
define mediastinum
what marks the superior mediastinum?
mediastinum = space between the lungs containing all the thoracic viscera apart from the lungs,like the heart
the superior mediastinum is bordered inferiorly by two lines, one at T4 for the posterior and one at the manubriosternal joint/sternal angle for the anterior
what does the superior mediastinum contain?
aortic arch and its branches:
1. brachiocephalic trunk (splitting into right subclavian artery and right common carotid artery)
2. left common carotid artery
3. left subclavian artery
the SVC (and its two tributaries, the L and R brachiocephalic veins)
the trachea and upper oesophagus
the inferior mediastinum is split into three
what are these three sections and what does each one contain?
Anterior = space between the posterior sternum and the anterior aspect of the pericardial sac (between front of the heart and the back of the sternum). has thymus remnants
Middle = the space where the heart is, including the ascending aorta, SVC, pulm. Trunk and pulm. Veins
Posterior = the space behind the heart (but in front of vertebrae) containing the oesophagus and descending aorta
external intercostal muscles -
which way do the fibres run, what are their origin and insertions and how does this mean they work?
oblique, running down and forwards like putting hands in lab coat pockets
origin is lower border of a rib, going down to insert to upper border of the rib below, so when the muscles contract in inspiration they pull the ribcage up and out (as the diaphragm flattens)
internal intercostal muscles -
what direction do the fibres run, origin and insertion and what this means for when they contract?
oblique but opposite to external, running up and forwards - grab your tits (together they form like an ‘X’)
origin = upper border of a rib, inserting on the lower border of the rib above, so when they contract in forced expiration, they pull the ribcage down and in
at what level does the horizontal fissure arise?
fourth rib
what is the cardiac notch?
a concavity in the anterior border of the left lung, made by an impression of the heart
innermost intercostal muscle -
direction of fibres?
function?
where do they lie?
same direction as internal intercostal (oblique, up and back)
same function as internal intercostal (pull ribcage down and in)
sit behind the internal intercostal muscles, with the costal groove in between
what are the three upper limb muscles?
pectoralis major
pectoralis minor
serratus anterior
pectoralis major and minor - what do they each connect to?
major = most superficial muscle to anterior chest wall, attaching to the sternum, upper humerus, clavicle and the upper 6 ribs
minor = deep to the major, attaches to the scapula (insertion) and ribs 3-5 (origin)
serratus anterior - what is this muscle and what does it connect to?
superficial muscle around the lateral side of the thoracic cage, attaching to the scapula- medial border? (insertion) and upper 8 ribs (origin)
what do the scalene muscles do?
arising form processes of the cervical vertebrae and inserting on 1st and second ribs, they assist in raising the 1st and 2nd ribs in inspiration
how are abdominal muscles involved in expiration?
pushing diaphragm up when they contract and inc. intraabdominal pressure
pulling lower ribs downwards
- What factors cause the lungs to expand and collapse as the thoracic cavity increases and decreases during respiration?
what contributes to increasng and decreasing throacic volume?
● Movements of the thoracic wall, intercostal muscles and diaphragm during inspiration increases the intrathoracic volume and diameters of the thorax. The consequent pressure changes result in air being drawn into the lungs (inspiration) through the nose, mouth, larynx, and trachea.
● During passive expiration, the diaphragm, intercostal muscles, and other muscles relax, decreasing intrathoracic volume and increasing intrathoracic pressure, expelling air from the lungs (expiration) through the same passages. Concurrently, intra-abdominal pressure decreases, and the abdominal viscera are decompressed
- A collection of gas or air within the pleural cavity is known as?
● Entry of air into the pleural cavity (pneumothorax) results from a penetrating wound of the parietal pleura. This results in partial collapse of the lung
- Why is a stab wound to the chest likely to cause the lungs to collapse?
● If a penetrating/stab wound opens through the thoracic wall or the surface of the lungs, air will be sucked into the pleural cavity because of the negative pressure. The surface tension adhering visceral to parietal pleura (lung to thoracic wall) will be broken, and the lung will collapse, expelling most of its air because of its inherent elasticity (elastic recoil). When a lung collapses, the pleural cavity (normally a potential space) becomes a real space
● What may be some of the consequences of a collapsed lung?
● There are varying consequences, some symptoms may be; fatigue, a sudden, sharp, stabbing pain in the chest, rapid breathing or shortness of breath (dyspnoea)
● How can the lungs be reinflated in the case of a pneumothorax?
● Inserting a chest tube into the pleura to remove air from the pleural cavity. The end that is outside of the body is connected to an underwater drainage
- What is the diaphragm made of and which nerve innervates it?
● The diaphragm is a curved muscular fibrous sheet that separates the thoracic from the abdominal cavity. The fibrous part occupies the centre of the diaphragm, and the muscular part lies in the periphery.
● It is innervated by the right and left phrenic nerves (C3-5)
- What would be the consequence of paralysis of the diaphragm?
● Paralysis of the diaphragm because of injury to the phrenic nerve results in the inability of the diaphragm to contract to allow proper inspiration
● Normally, during inspiration, the diaphragm contracts and flattens, however the paralysed dome ascends as it is pushed superiorly by the abdominal viscera that are being compressed by the active contralateral dome. Instead of ascending during expiration, the paralysed dome descends in response to the positive pressure in the lungs
It is important to detect lung cancer in the early stages because the treatment depends on its stage. A tumour found in the lungs can have consequences on structures within the mediastinum.
● What structures within the mediastinum can the tumour invade and what are the consequences of the invasions of structures within the mediastinum?
● The primary tumour of the lung can metastasise and spread, not all lung cancers will spread. But if they spread they are likely to go to nearby lymph nodes and invade the mediastinum.
● The consequences of spread into the mediastinum include: spinal cord compression, spread to nearby structures such as the heart, lining around the heart (pericardium), and great vessels (aorta and vena cava), compression of the trachea results in respiratory insufficiency and compression of the oesophagus resulting in difficulty in swallowing
during inspiration, what dimensions increase?
lateral/transverse, antero-posterior and vertical
anterior of the ribs is ___ to the posterior
inferior
describe what is meant by the bucket handle movement
refers to the movement of the ribs during inspiration -
the lateral shafts of the ribs elevate, like a bucket handle being lifted
describe what is meant by the pump handle movement
refers to the movement of the sternum during inspiration - it moves up and out (superior and anterior) then when muscles relax in expiration moves back down, like a water pump handle
describe all aspects of the pleura
two membranes surrounding the lungs - Resting lungs would actually collapse inwards due to their elastic nature.
The chest wall would tend to expand.
So these forces act in opposite directions on the pleural membranes, they find a balance.
This creates a subatmospheric pressure between the two membranes
inner one = visceral
outer one = parietal
space between = pleural space/cavity, filled with serous fluid for lubrication
describe the features common to both lungs
apex - lies above first rib
costal, mediastinal and diaphragmatic surfaces (one facing ribs, one facing the middle/back, one facing diaphragm)
Hilum - an indent of the root of the lungs for structures such as veins arteries and bronchi to pass through
what is different between the two lungs?
right = bigger with two fissures, horizontal and oblique, to give you three lobes, superior, middle, and inferior
left only has oblique fissure so only superior and inferior lobes
its smaller as it has space for the heart
left has the lingula, little flap on end of the superior lobe
the hilum of the lung - where is it located and what is the typical layout of the structures in it?
located on the mediastinal surface of each lung from T5-T7
each will have a pulmonary artery, two pulmonary veins and the bronchi
typically the bronchus is posterior to the pulmonary artery
the pulmonary artery is superior to the pulmonary veins
you can also see vena cava, oesophagus and there should be some bronchial arteries/veins
how is the
1. pulmonary artery
2. bronchi
distinguishable in the hilum?
- large lumen
- thick walls/ rings of cartilage
bronchi - where does the trachea bifurcate?
sternal angle/ manubriosternal joint /T4 / second rib
how do the right main bronchus and left main bronchus split?
what do lobar bronchi split into?
right = enters hilum as it splits into superior lobar bronchus and the bronchus intermedius which splits into middle and lower lobar bronchi (so three, one for each lobe)
lobar bronchi split into segmental bronchi
left = superior and inferior lobar bronchi
which bronchi is more likely to be blocked when choking?
right, as it is wider, shorter and falls more vertically
the thoracic diaphragm is where?
base of the lungs, at the inferior thoracic aperture, separating thoracic cavity from abdominal cavity
what does the diaphragm do?
it is the primary muscle of respiration and also acts as a passageway for the descending aorta, oesophagus and the inferior vena cava from thorax to abdomen
the diaphragm is innervated by the phrenic nerve, which consists of spinal nerves ___?
the phrenic nerve has peripheral attachments to what?
spinal nerves C3-C5
has peripheral attachments to the xiphoid process of the sternum
the costal margins of ribs 7-10 (direct attachments to ribs 11 and 12)
the lumbar vertebrae and arcuate ligaments (these connect the diaphragm to the spine)
how can you spot the phrenic nerve?
the phrenic nerve runs anterior to the root of the lung
what does the vagus nerve do to the thoracic viscera?
the vagus nerve, or CN X, enters the thoracic superior aperture to provide parasympathetic innervation
how can you spot the vagus nerve in the thorax?
the vagus nerve runs posteriorly to the root of the lung
