ICL 1.0: Thoracic Wall, Pleura and Lungs Flashcards
what is the thorax?
an irregular shaped cylinder with a narrow opening, the superior thoracic aperture, which is connected to the neck superiorly and a relatively large opening, the inferior thoracic aperture, inferiorly
the diaphragm closes this cavity and doesn’t allow for communication between the abdomen and thorax
what is the normal size of the thorax in adults vs. kids and elderly?
adults: the anterioposterior (AP) diameter of the thorax is shorter than the transverse (lateral) diameter with a ratio of 1:2
so an adult should be twice as wide as they are front to back
elderly and childhood: the AP diameter is a little shorter than or nearly equals to the transverse diameter, making the thorax cylindrical
what are the types of irregular chest shapes?
- barrel chest
- pigeon breast
- funnel breast
- funnel breast
- kyphosis
- scoliosis
- lordosis
what is barrel chest?
AP diameter compared to transverse diameter is 1:1
the person literally looks like a barrel
what is pigeon breast?
pectus carinatum
AP diameter is increased
looks like the sternum is jutting out
what is funnel breast?
pectus excavatum
looks like the sternum is caved in
what are the 10 natural landmarks of the chest?
- suprasternal notch: (trachea)
- manubrium sternalis
- manubrosternal angle** (angle of louis)
- suprabdominal angle: (infrasternal angle) dome part of the diaphragm
- xiphoid process
- ribs
- intercostal space
- scapula
- spinous process:
- costolspinal angle: (very close to the kidney and ureter)
SLIDE 6
what is the significance of the sternal angle?
helps distinguish superior from inferior mediastinum
where is the suprasternal notch located?
T2
where is the manubrosternal angle located?
T4
where is the xiphisternal angle located?
T9
what are the artificial vertical lines of the chest?
- anterior midline
- midclavicular line (one of the left and right)
- sternal lines
- axillary lines
- scapular line
- posterior midline
SLIDE 8
what is the importance of the midclavicular line?
midclavicular line on the left will align to the apex of the heart!
what are the 3 parts of the sternum?
- manubrium
- body
- xiploid process
SLIDE 10
2nd costal notch is aligned with the sternal angle
which ribs articulate with the sternum?
ribs 1-7 = the “true ribs”
what are the 3 types of ribs?
- true (1-7)
- false (8-10)
- floating (11-12)
the true ribs articulate directly with the sternum while the false ribs are connected by one piece of cartilage to the sternum
what type of cartilage is the costal cartilage?
hyaline cartilage
what is the function of the costal cartilage?
it prolongs the ribs and gives them elasticity! as you get older your ribs become calcified
what is the importance of the superior thoracic aperture?
the thoracic outlet is the communication between the thorax and the neck
the superior thoracic aperture refers to the superior opening of the thoracic cavity. It is also referred to anatomically as the thoracic inlet and clinically as the thoracic outlet. The clinical entity called the Thoracic outlet syndrome refers to the superior thoracic aperture, not the inferior thoracic aperture.
if you have infections of the neck they can ascend and pass through the superior thoracic aperture and get to the thorax!
the lungs also pass through this thoracic outlet and extend above the clavicle
what is the inferior thoracic aperture?
the inferior thoracic aperture is much larger than the superior thoracic aperture
it is the round opening whose edges are the lowest ribs
it is closed by the diaphragm, which separates the thoracic and abdominal cavities
what are the functions of the thoracic cage?
- respiration
- protection of the viscera –> chest and abdominal viscera! because the ribs go down very low and protect the kidneys and liver etc.
- anchor points for skeletal muscles
what is the anatomy of the rib?
slide 17
- head
- neck
- tubercle
- costal angle
- body (shaft)
- costal groove
what are the 3 structures found in the costal groove of the rib?
intercostal vein, nerve, artery
VAN (top to bottom) –> this is why you have to avoid doing injections at the bottom of ribs because you’ll hit the nerve and it’ll hurt a lot
how do ribs allow for respiration?
the ribs have to elevate and depress during reparation so the costovertebral joint is how they do it!
the rib and the vertebra will always have the same number!
what is the role of the thoracic cage in respiration?
- ventilation
- inspiration
- quiet inspiration
- active inspiration
what is ventilation?
the movement of air into (inspiration) and out of (expiration) the lungs
what is inspiration?
requires an increase in the volume of the thoracic cavity that produces a negative air pressure in the lungs that draws air into the respiratory tract
what is quiet inspiration?
diaphragm contracts > lowers diaphragm > increase in vertical dimension of thoracic cavity
what is active inspiration?
other respiratory muscles contract > elevate ribs > increase in transverse and anterior-posterior dimensions
what is the difference between quite vs. active expiration?
quiet expiration = passive, powered by recoil of elastic fibers in the lungs
active expiration = abdominal muscles contract
what allows for change in the vertical axis of the thoracic cavity?
diaphragm
what allows for change in the anterior-posterior axis of the thoracic cavity?
ribs and sternum
it’s called the pump handle movement
what allows for change in the transverse axis of the thoracic cavity?
ribs
bucket handle movement
what are the components of the thoracic wall?
- peripheral muscles
- intercostal muscles (external, internal and innermost)
- neurovascular bundle in the costal groove
- transverse thoracic muscles
- subcostal muscle
- endothoracic fascia
- parietal pleura
SLIDE 25
what is the neuromuscular bundle in the costal groove of the ribs?
- vein: drain into azygous system and internal thoracic vein
- artery: anterior and posterior intercostal arteries
- nerves – ventral rami of T1-T11, T12 -subcostal
VAN = top to bottom is vein, artery, nerve
so if you do a chest injection you need to avoid the bottom of the rib so you don’t hit any of these structures! specifically the intercostal nerve will really hurt the patient if you hit it –> so the best place to put a needle is in the middle of the space between ribs
how do the intercostal muscles attach to the sternum and vertebrae?
membranes!
don’t dissect towards the sternum because the first thing you’ll see is a membrane!
the best place to see all the layers of the 3 muscles is the lateral part of the rib cage
SLIDE 26
what does the intercostal artery anastomose with?
posterior intercostal artery anastomoses with the internal thoracic artery
outside the intercostal muscles, what are the other thoracic muscles?
- subcostals
- transversus thoracis
slide 27
what are the 3 regions of the thoracic cavity?
left lung, right lung and the mediastinum!
the mediastinum is the center of the chest, literally everything is located there
what is the pleura?
a membrane that covers the lungs and internal chest
what are the parts of the pleura?
visceral pleura which is attached to the lungs (inner pleura)
parietal pleura which is attached to the wall of the cavity (outer pleura)
and in between there is the pleural cavity!
slide 30
what are the divisions and recesses of the parietal pleura?
- cervical pleura (Cupola)
- costal pleura
- diaphragmatic pleura
- mediastinal pleura
- costodiaphragmatic recess
- costomediastinal recess
slide 32 and 33
what are pleural recesses?
recesses are pockets where the pleura is coming from the chest wall and they sort of form a sac
it’s where the pleural cavity extends a little more than you’d think
if someone is stabbed in a recess, air will come into the pleural cavity and you’ll get a collapsed lung and probably also effect the liver if you get stabbed on the right side
where is the endothoracic fascia located?
it’s in between the pleura and the rib!
slide 35
how many lobes do the lungs have?
right lung has 3 lobes = superior lobe separated by the horizontal fissure from the middle lobe separated by the oblique fissure from the inferior lobe
left lobe has 2 lobes = superior and inferior lobe separated by the oblique fissure
slide 37
what are the anatomical parts of the right lung?
apex and base
3 SURFACES
Costal
Diaphragmatic
Mediastinal
2 FISSURES
Oblique
Horizontal
3 LOBES
Superior
Middle
Inferior
what is the pulmonary ligament?
the parietal pleura surrounding the root of the lung extends downwards from the hilum in a fold called the pulmonary ligament
at the lower edge of each lung the pleural layers come into contact with each other and terminate in a free curved edge
it attaches the lung to the diaphragm
what is the hilum of the lung?
the hilum of the lung is a triangular impression that allows the structures which make up the root of the lung to enter and exit
a hilum is a section of an organ where other types of structures like veins or arteries can enter
the hilum of the lung is a wedge-shaped section in the central area of the lung that permits arteries, veins, nerves, bronchi, and other structures to enter and exit
both human lungs have a hilar region, meaning both lungs have an area called the hilum
this region aids the lung’s root in anchoring the lungs to the heart,trachea and other structures
what are the roots of the lung?
root of the lung are all the structures entering or leaving the lung at the hilum, forming a pedicle invested with the pleura; includes the bronchi, pulmonary artery and veins, bronchial arteries and veins, lymphatics, and nerves
the hilum is the region where the roots of the lungs get in – so the kidney also has a hilum because it’s where the arteries, veins and ureter come through!
what is the lingula?
a tongue-shaped segment of the upper lobe of the left lung
slide 42
what is the cardiac notch?
the cardiac notch is part of the left lung that lies along the fifth and sixth intercostal space, and the spaces can be used to access the heart in pericardiocentesis to relieve cardiac tamponade
slide 41
what is the carina?
the bifurcation of the bronchioles
the right bronchiole is always straight while the left is always inclined due to the heart – so if something gets into your airway it’ll probably go to the right lung
slide 44
what are the names of the primary, secondary and tertiary bronchioles?
primary is bronchiole
secondary is lobar
tertiary is segmental
what are the bronchopulmonary segments?
bronchopulmonary segmental anatomy describes the division of the lungs into segments based on the tertiary bronchus
each segment has its own pulmonary arterial branch and thus, the bronchopulmonary segment is a portion of lung supplied by its own bronchus and artery.
each segment is functionally and anatomically discrete meaning that a single segment can be surgically removed without affecting its neighbours
slide 47 (don’t need to memorize)
what is the difference between segmentectomy and lobectomy?
removing a segment vs. a whole lobe of a lung
what is the parasympathetic innervation of the lungs and visceral pleura?
vagus nerve via the pulmonary plexus
this allows for bronchoconstriction, vasodilation and secretion aka the cough reflex!
what is the sympathetic innervation of the lungs and visceral pleura?
paravertebral sympathetic ganglia via the pulmonary plexus
this allows for bronchodilator, vasoconstriction and inhibits secretion
this has NO visceral pain so the lungs will never have pain! the pain comes from the parietal pleural, NOT the visceral pleura
what is the innervation of the parietal pleurae of the thoracic cavity?
- intercostal nerve innervates the costal pleura and diaphragmatic pleura
- phrenic nerve innervates the center of the diaphragm
so the parietal pleura is sensitive to pain!!
what are the clinical conditions related to the pleura?
- pneumothorax
- hemothorax
- chylothorax
- pleuritis
what passes through the inferior thoracic aperture?
- inferior vena cava
- esophagus
- abdominal aorta
- thoracic duct
