Lecture 17: Thoracic wall; Pleura and Lungs Diaphragm Flashcards
What comprises the osseous (bony) part of the thoracic wall
Vertebral column, ribs, and sternum
What are the other non-osseous structures in the thoracic wall
muscle, cartilage, fibrous tissues
Compare the shapes of the thoracic cavities in adults and children
Adult- Oval
Child- Circular
What are the boundaries of the thoracic inlet
Clavicles, sternum, first ribs, and vertebral column
Which aspect of the thoracic inlet is higher, the dorsal or ventral
Dorsal is higher than ventral
What is the dorsal landmark of the thoracic inlet
T1
What is the ventral landmark of the thoracic inlet
Manubrium of sternum
Is T1 higher or lower than the manubrium of the sternum
higher
What does the difference in ventral and dorsal heigh of the thoracic inlet allow
Allows the apical portion of the lungs to rise into the root of the neck.
Why is it important to know that the lungs can extend into the root of the neck?
As physician- patient comes in with neck injuries, need to check if lungs are good
Boundaries of thoracic outlet
Inferior- diaphragm Posterior- T12 Lateral- Ribs 10-12 Anterior- Costal cartilages of ribs 7-10 As well as the junction between the body and xyphoid process of sternum
Which is wider the thoracic inlet or outlet
outlet
Jugular notch (or suprasternal notch)
notch at the midline of the manubrium
Sternal angle or Angle of Lewis
Acute angle that forms when the manubrium meets the sternal body
What is the clinical significance of the Angle of Lewis
The angle is easily palpable on all patients and is an important landmark for physical exams for using a stethescope
What are the vertebral levels of the Angle of Lewis
T4-5
Which costal cartilage attached the the sternal body inferior to the sternal angle?
Costal cartilage of rib 2 Important landmark for clinical exams
Describe the movements of the costosternal articulations
gliding type
At what vertebral level does the xiphoid process attach to the sternal body
T10
What is the most commonly fractured site on the sternum
sternal angle
Why are fractures to the sternum more common in kids than adults
Because in kids the sternum is not completely fused together (broken into segments) verses the adult sternum which is completely fused together
Why are features to the sternum uncommon
Forces at the sternum are dissipated into the ribs, which are not as strong as the sternum causing those to break instead
What injuries should you be concerned about if a patient comes in with a fractured sternum
diaphragmatic lacerations, herniation of abdominal contents into the thoracic cavity, heart trauma.
True ribs
Ribs 1-7: Ribs that have costal cartilages that attach directly to the sternum
False ribs
Ribs 8-9: Ribs have costal cartilages that attach to the superior adjacent costal cartilage.
Floating ribs
Ribs 11-12: These are a type of false rib. These ribs have no anterior articulation but still articulate posteriorly to the vertebral bodies and transverse processes
Why is it important to know which ribs are directly connected to the sternum
Because if a patient suffered a blow to the sternum you know you should look for breaks in the true ribs since theses are the ribs that dissipate the force
Know the anatomy of a typical rib
USE YO BONE BOX
Typical rib
2 facets with articulate with the same numbered vertebrae and with the vertebra superior to it. lateral the hear is a constricted area called the neck. An articular tubercle lies just dorsal to the junction of the neck and the rib body. The anterior sternal extremity is roughened to allow for the attachment of a costal cartilage. Superior surfaces of the ribs are round and smooth. Inferior surface is grooved
How are the neruovascular bundles arranged in the intercostal spaces
Inferior to a rib (VAN)- Vein, artery, nerve
When a patient suffers force to the side of the body and fractures a rib, what would you expect to see/feel from the fracture
May not be able to palpate the fracture but there could be a puncture into the pluera or lung
When a patient suffers force front the front of the body to the back (or vice versa) and fractures a rib, what would you expect to see/feel from the fracture
Would be able to palpate the fracture. Wouldn’t be as worried about damage to the thoracic wall
What connects the costal cartilage to the sternum
ligatments
What attaches the bony part of the rib to its costal cartilage
fibrous tissue
What is it called when the ligaments or fibrous tissue of the ribs is inflamed
Costochondritis
Why is it that people with back injuries have trouble breathing
because the ribs articulate with the vertebral column. Also after open heart surgery, many patients complain of back pain due to the forces appiled to the posterior attachments of the ribs because of cutting the sternum and retracting the rib cage.
What may occur if there is an obstruction (or coarctation (or narrowing)) of the aorta
Rib notching
Explain the mechanism of rib notching
When the aorta is constricted, pressure builds which causes the intercostal arteries to form “squiggles” resulting in notches to form on the inferior border of ribs
Why does rib notching occur on the inferior border of the ribs
because that is where the neuromuscular bundles lie
Why is it important to know that the neurovacqlar bundles are inferior to the rib?
Because when you need to insert a chest tube into a patient you need to make sure you puncture the intercostal space region without hitting the neuromuscular bundle
What are the consequences of hitting the neuromuscular bundle with a chest tube
hemothorax- blood will seep out of the vessels and into the lungs
Will we see rib notching taking place is collateral circulation is being utilized to to malfunctions in other arteries
Yes because more blood is being forced through these vessels, resulting in a greater build up of pressure and thus leading to notches in the inferior borders of the ribs
What is special about the first rib
It is the highest, widest, strongest, flattest, shortest, and most curved rib
Where does the first rib lie
Almost completely beneath the clavicle
What attaches to the undersurface of the first rib
subclavius m. and costoclavicular ligament
What may be the first sign of cancer in the breast or prostate gland and why
rib pain may be a first sign because ribs are frequent sits of metastisis
Why are rib fractures less common in children
The rib cage is more flexible at younger ages
What other injuries are rib fractures associated with in general
hemothorax and pneumothorax
What injuries are associated with lower rib fractures
tears in diaphragm
What are the two categories of costovertebral articulations
- Articulations of the rib heads with one or two vertebral bones
- Articulation of rib necks and tubercles with vertebral transverse processes
What type of joint does a typical rib form with a articular facet on the dorsolateral margin of 2 adjacent vertebra? And also between the articular surface of the tubercles and neighboring transverse processes.
Sliding joint
What are the ribs with costotransverse process articulations
ribs 1-10
For the true ribs, what type of joint is present between the costal cartilage and the sternum
Sliding (EXCEPT FOR THE FIRST RIB)
What is the type of joint present between the costal cartilage of the 1st rib and the sternum
synovial joint
What are the names of the 3 intercostal muscles
External and internal intercostal muscles, and innermost intercostal muscle
Which muscle comprises the most superficial layer of the intercostal space?
enternal intercostal m
What direction do the fibers of the external interacts muscles travel
from lateral to medial (same direction as the external oblique)
In which direction (anterior or posterior) is the external intercostal m. membranous and muscular
Membranous- anterior
Muscular- posterior
How are the internal intercostal muscle fibers arranged relative to the external intercostal fibers
Perpendicular to external intercostal m.
In which direction (anterior or posterior) is the internal intercostal m. membranous and muscular
Membranous- posterior
Muscular- anterior
Where do the internal intercostal muscles arise and end?
Arise at the sternum and extend to the midaxillary line (love handle side) where it ends in a membrane
What is unique about the membrane and muscular patterns of the internal and external intercostal muscles
They alternate, allowing you to differentiate between the two muscles without reflecting back a layer of the external intercostal muscles.
What muscles are deep to the internal intercostal m.
The innermost intercostal muscles
Where are the innermost intercostal muscles located
Only at the midaxillary line (peters off at the enters anteriorly and posteriorly)
What muscles are located in the same plane as but are more posterior to the innermost intercostal muscles
transversus thoracis muscles
Function of the transversus thoracic muscles
Hold the internal thoracic (mammary) vessels in place
How are the internal, external, and innermost intercostal muscles innervated and supplied
By their respective neuromuscular bundle
Action of the intercostal muscles
Involved in inspiration and expiration: At one point it was thought that the external muscles were involved in inspiration and the internal where involved in expiration
Do the true ribs and the false ribs move in the same directions during inspiration and expiration to expand and compress the chest cavity
No
For the true ribs, what motion do the ribs along with the sternum move during inspiration and expiration
Like a pump handle (Anterior to posterior) to increase the A-P diameter of the chest.
For the false ribs, what motion do the ribs along with the sternum move during inspiration and expiration
Like bucket handle which increases the width of the lower rib cage
What dimensions of the chest cavity does the diaphragm enlarge during expiration and inspiration
the vertical dimensions
What are the 2 main arterial supplies to the thoracic wall
The intercostal a. and the beaches coming off of subclavian and axillary arteries
Where do the posterior intercostal arteries arise from for the lower 9 intercostal spaces
the thoracic aorta
What are the upper 2 branches of the intercostal spaces on the posterior supplied by (since the lower 9 we know are supplied by the posterior intercostal a)
superior intercostal a
What is the superior intercostal a a branch of
axillary a (block 1)
What do the posterior intercostal arteries anastomose with
The anterior intercostal a.
From what vessel do the anterior intercostal a. arise from
The internal thoracic a.
What do the anterior intercostal arteries supply?
The intercostal spaces and overlaying skin
At what intercostal space does the internal thoracic artery divide
6th
What are the two branches of the internal thoracic a and where are they located
Musculophrenic a- thorax
Superior epigastric a- abdomen
What is the internal thoracic artery a branch of?
Subclavian a
Is an intercostal nerve also considered a ventral rami?
Yes (just given the name intercostal nerve due to its location)
What does the posterior primary rams supply in the thorax
Intrinsic back muscles and skin
Where does the ventral rams course in the thorax
Along the chest wall between the innermost intercostal m. and the internal intercostal m.
When does the ventral ramus give off its lateral branch
At the midaxillary line
What are the terminal branches of the lateral branch of the ventral ramus
porterior and anterior
What does he lateral branch of the ventral ramus innervate
The overlaying muscle and skin
Where are the terminal branches of the lateral branch of the ventral ramus given off to
overlaying skin
When does the ventral rams give off its anterior terminal branch
At the lateral border of sternum
What do the anterior terminal branches of the ventral rami innervvate
overlaying skin
What are the 2 different branches of the anterior terminal branch of the ventral rami
lateral and medial branches
What skin does the lateral and medial branches innervate?
The lateral and anterior respectively
What are the 3 groups of lymph nodes in the thorax
Pectoral nodes, axillary nodes, and internal thoracic nodes
Which lymph nodes are commonly associated with breast tumor metastasis
Internal thoracic nodes
Pleura verses peritoneum
Same concept except pleura is in the thoracic cavity verses peritoneum which is in the abdomen
Parietal and Visceral pleura
Visceral- touches the lungs
Parietal- Surrounds the inner wall of the thorax, diaphragm, and lateral structures of mediastinum
Pleural cavity
Space between the visceral and parietal peritoneum. Serous fluid and no air present
What is the condition where an individual has air in the pleural cavity
pneumothorax
How is parietal pleura named
Based on its location, for example, the mediastinal pleura, diaphragmatic pleura
What is the one part of the pleura that protrudes outside of the thoracic region and above the clavicle
Cupula- pleura over the apex of the lung and extends into the root of the neck
Costodiaphragmatic recess
Reflection of parietal pleura off the diaphragm into the inner chest wall. This is the lowest point in the pleural cavity. Located between the ribs and diaphragm
What is the name of the condition where the pleural cavity is compromise and blood enters the lungs
Hemothorax
Where does the apex of the lung protrude into?
Above the first rib and clavicle into the root of the neck
Where does the base of the lung rest
Superior surface of diaphragm
What are the two major surfaces of the lungs
Costal surface and mediastinal surface
Costal surface of the lings
Lies against the inner surface of the rib cage
Where is the mediastinal surface located
Adjacent to the heart
What is located on the mediastinal surface of the lungs
hilum
What enters and leaves the hilum and in what order
(Alpha order): ABV: Artery, bronchi, and vein. The artery and veins are pulmonary arteries in veins. This goes from highest to lowest (most superior to inferior)
What is unique about the pleura at the hilum
The visceral pleura is continuous with the parietal
How many lobes does each lung have? How many fissures?
Right- 3 lobes 2 fissures
Left-2 lobes 1 fissure
What are the names of the 2 fissures for the right lung
- Oblique (major)
- Horizontal (minor)- separates the superior from the middle lobe
What’s the name of the fissure for the left lung
-Oblique (major)
What are the names of the 3 lobes of the right lung
-Superior, middle, inferior
What are the names of the 2 lobes on the left liver
Superior and inferior
Where could you put a stethoscope to hear the superior lobe of the right lung
On the anterior thoracic wall not bellow the sternum
Where could you put a stethoscope to hear the middle lobe of the right lung
At the Xiphoid process of the sternum
Where could you put a stethoscope to hear the inferior lobe of the right lung
On the back
Where could you put a stethoscope to hear the superior lobe of the left lung
Front at the xiphoid
Where could you put a stethoscope to hear the inferior lobe of the left lung
On back can go pretty high or low
Make sure you look at radiographs of the lungs and can differentiate where each lobe is
Okay
Look at slide 35 to see that different places where you put a stethoscope to hear the different lobes of the lungs
Okay
When looking at the hilum of the longs other than where things are oriented, how can you tell what each hole is
By looking at the thickness of the walls. Bronchi have very thick walls and the vessels are much thinner
What is the cardiac notch and which lung has it?
The cardiac notch is the place where the lateral border of the left ventricle has made contact with the lung. This is on the left lung
What is the candy cane looking impression on the left lung
Groove for the descending aorta
From the anterior, lateral, and posterior views, do the lungs and pleura extend down to the same height
No
From the anterior view, what rib do the lungs extend to?
Rib 6
From the lateral view, what rib do the lungs extend to?
Rib 8
From the posterior view, what rib do the lungs extend to?
Rib 10
From the anterior view, what rib does the pleura extend to?
Rib 8
From the lateral view, what rib does the pleura extend to?
Rib 10
From the posterior view, what rib does the pleura extend to?
Rib 12
Knowing the extent of which the lung and pleura can extend follows what rule
the rule of twos
Why is it important to know where the lungs and pleura extend
For pleural taps (example taking a needle and placing is inferior to rib 8 and posterior to rib 10 would be good from the lateral)
What delivers deoxygenated blood to the lungs?
Pulmonary arteries
What is the arterial supply to the lungs
bronchial a.
Where do the bronchial a. deliver oxygenated blood to
parenchyma
What returns oxygenated blood to the heart
Pulmonary veins
What innervates the lungs and pleura
vagus n and the sympathetic nerve plexus
Do the lungs receive parasympathetic or sympathetic innervation
Both
Is the innervation to the pleural autonomic or somatic
Both
What provides somatic innervation to the pleura
intercostal n, and the phrenic n.
Which part of the diaphragm is normally higher and why
The right because of the large liver
What comprises the periphery of the diaphragm and the center
Periphery- Skeletal muscle
Central- Tendinous (Central tendon)
What arteries supply the superior surface of the diaphragm
Musculophrenic a (branch of internal thoracic a, pericardiophrenic a
What supplies blood to the inferior surface of the diaphragm (Abdomen)
The inferior phrenic a.
What nerve fibers innervate the diaphragm along the periphery
The intercostal n.
Do intercostal nerves supply sensory or motor innervation
sensory
What innervates the central portion of the diaphram
Phrenic n (C3,4,5)
Does the phrenic nerve provide sensory or motor innervation?
Both
Where does the phrenic give off sensory innervation? Motor innervation
Sensory- Central tendon
Motor- muscles of diaphragm
Where does the inferior vena cava go through the diaphragm and why is this important?
At vertebral level T8 through the Inferior vena naval foramen. This foramen is located in the central tendon which is important because the IVC would be constricted each time the diaphragm contracted if it were located in the muscle
Where does the esophagus go through the diaphragm and why is this important?
Through the esophageal hiatus at vertebral level T10. The hiatus is formed by two cura of the diaphragm. Here we want to have the esophagus surrounded by muscle of the diaphragm to create a sphincter
Where does the aorta go through the diaphragm and why is this important?
At vertebral level T12 through the aortic hiatus. The aorta crosses posterior to the diaphragm and is therefore unaffected by contraction of the diaphragm.
