Module 01 - Thoracic Region Flashcards
What is a septum?
A wall or partition dividing a body space of cavity each named according to its location
Describe the diaphragm structurally
Thin musculotendinous septum that separates the thoracic and abdominal cavities
Its structure comprises 2 domes; left and rise, a central tendon, and crus
What is the principal muscle of respiration?
Diaphragm
What do respirologists call the domes of the diaphragm?
right and left hemidiaphragm
How many domes does the diaphragm have? + what are they called
2
Right dome
Left dome
How high can the right dome rise?
Upper border of the fifth rib
How high can the left dome rise?
Lower border of the fifth rib
Where do the peripheral muscular fibers of the diaphragm attach?
Central Tendon
Where is the Central Tendon located?
Just inferior to the fibrous pericardium of the heart
What is the right crus?
muscuolotendinous extension of the diaphragm that originates from the front of the bodies of the upper THREE lumbar vertebrae - on the right side
What is the left crus
muscuolotendinous extension of the diaphragm that originates from the front of the bodies of the upper TWO lumbar vertebrae - on the left side
Name two differences between right and left crus
Right crus is on the RIGHT anterior side of the Upper 3 lumbar vertebrae
Left crus is on the LEFT anterior side of the upper 2 lumbar vertebrae
How many apertures are there in the diaphragm? What are they
3
Caval Opening
Esophageal Hiatus
Aortic Hiatus
What is an aperture?
an opening that allow passage of key structure
Where is the Caval Opening?
At the level of the 8th thoracic vertebra, in the posterior thorax on the right side
What structure passes through the caval opening?
Inferior Vena Cava (IVC)
What is the esophageal hiatus?
It is an aperture (opening) in the the diaphragm that allows the passage of the esophagus through the diaphragm
Where is the esophageal hiatus?
In the muscle of the right crus, at the level of the 10th thoracic vertebra
Where does the esophagus lie in its thoracic portion
As it descends through the thorax it deviates left, lying anterior to the thoracic aorta
Where is the aortic hiatus?
between right and left crus, anterior to the 12th thoracic vertebra - it is on the left side of the posterior thorax
What’s the mnemonic to remember all three apertures of the diaphragm?
I ate 10 eggs at 12
IVC T8 T10 Esophagus Aorta T12
What direction do the fibres of external intercostals run?
Anteroinferiorly from the lower border of the rib.
“Hand in your pockets” - runs same direction as your hand if you were to put them in your pockets
What direction do the fibres of internal intercostals run?
Posterosuperiorly from the upper border of the rib
What direction do the fibres of innermost intercostals run?
Posterosuperiorly from the upper border of the rib
Which movements can result in an intercostal muscle strain?
Twisting and reaching upwards
What are the 3 components of the sternum (start superiorly and make your way down)?
Manubrium
Body
Xiphoid process
What are the 2 joints of the sternum?
Manubriosternal joint (manubrium/body) Xiphisternal joint (xiphoid process/body)
What is the angle of Louis
Also known as the sternal angle
It’s the manubriosternal joint
At what “vertebrae height” is the manubriosternal joint?
in line with 4th and 5th thoracic vertebrae
At what “vertebrae height” is the xiphisternal joint?
9th thoracic vertebrae
What is another name for the breast bone?
sternum
Name 2 important procedures where the anatomical landmarks are provided by the sternum?
CPR, inserting a chest tube
At the superior edge of the manubrium there is a notch, what is it called?
jugular notch
How many thoracic vertebrae are there
12
What are the functions of the thoracic vertebrae? (2)
support the weight of the upper body and protect the spinal cord
What structures form the vertebral foramen to protect and house the spinal cord?
Vertebral Arch (which includes the pedicle and lamina)
and
The body of vertebrae
What structure forms the intervertebral foramen to protect and house the spinal nerves?
Pedicle
What structures provide the attachment sites for muscles and nerves?
Spinous process
Transverse process
Body of vertebrae
What are intervertebral discs?
Cartilaginous joints that act as shock absorbers and allow for some (though minimal) movement
What are the 2 components of the intervertebral discs?
Outer annulus fibrosus
Central nucleus pulposus
Describe the annulus fibrosus
Outer ring of the intervertebral disc. Its made up of fibrocartilage (contains bundle of collagen fibres). Its role is to resist shear forces (unaligned forces pushing one part of a body in one specific direction)
Most visible part of the vertebrae
Describe the nucleus puposus
Gelatinous structure that functions to resist compressive force (pushes inward on an object causing it to be compacted)
What is the anatomical relationships between the annulus fibrosis and nucleus pulposus and the vertebrae?
Discs sit in between vertebral bodies
They DO NOT come into contact with the contents of the intervertebral foramen or vertebral foramen (unless there is damage to the disc)
Name one condition that refers to structural damage of a intervertebral disc?
Herniated disc
What is a herniated disc?
Bulging of the nucleus pulposus through weak spots of the annulus fibrosus.
If the the annulus fibrosus ruptures completely, the protruding nucleus pulposus can compress the contents of the intervertebral foramen, such as the spinal nerve
Symptoms:
back pain, numbness weakness due to compressed nerve
What is the function of the ribs?
protect the thoracic cavity
where are the ribs located?
deep to the skin and superficial to the thoracic cavity
What are some injuries that can occur to the ribs?
fracture
bruising
inflammation
Describe the symptoms of a rib fracture?
Injury internal organs such as the lungs causing localized chest and back pain
May result in injury to intercostal veins and arteries, causing minor hematoma or injury to intercostal nerves causing localized pain
describe the symptoms of bruising over a rib
localized pain and swelling of that area
describe the symptoms of inflammation in the ribs area
inflammation of costal cartilage results in chest wall pain that can affect a region spanning more than one rib
Where are the intercostal veins, arteries, and nerves located ?
within the costal groove of each rib
What is the function of intercostal veins and arteries?
supply intercostal muscles
what is the role of intercostal nerves?
supply motor and cutaneous innervation to this area
In what order (superior to inferior) can you find the intercostal veins arteries and nerves?
VANs
Vein (superior most)
Arteries
Nerves (inferior most)
What are the 2 apertures in the thoracic wall?
Thoracic inlet
Thoracic outlet
Where is the thoracic inlet and what is its function?
Superior aperture formed by: manubrium, rib 1, body of T1
Allows passage between the thorax an neck
Where is the thoracic outlet and what is its function
Inferior aperture formed by the xiphoid process, costal margin, rib 11 & 12 and body of T12
Allows passage between the thorax and abdomen
What is thoracic outlet syndrome?
Contrary to the name, it is associated with the thoracic INLET
Occurs when blood vessels or nerves passing through the thoracic inlet are compressed
Causes:
physical trauma, repetitive injuries from job or sport related activities, anatomical defect and pregnancy
symptoms:
pain in shoulder and neck, numbness of fingers
What are the main blood vessels that supply the thoracic wall?
Internal thoracic arteries aka internal mammary arteries
- Right internal thoracic artery
- Left internal thoracic artery
Where are the thoracic arteries located?
Lateral to the sternum, on each side
What is the thoracic aorta?
portion of the aorta that descend through the thoracic cavity
Which blood vessel gives rise to the anterior intercostal arteries?
Internal thoracic arteries
Which blood vessels give rise to the posterior intercostal arteries?
Thoracic aorta
Where can you find the anterior intercostal arteries?
travel posteriorly around the thoracic wall in the costal grooves of a rib
What are anastomosis?
Direct connection between two blood vessels
How are the anterior and posterior intercostal arteries connected?
by an anastomosis
Where are the posterior intercostal arteries located?
Travel anteriorly to anastomose with the anterior intercostal arteries
what are the subcostal arteries?
the 12th pair of arteries in the intercostal space.
The run INFERIOR to the costal margin instead of in the costal groove like intercostal arteries
What are the veins of the thoracic wall
Similarly to the arteries
Anterior intercostal veins
Posterior intercostal veins
Subcostal veins
Where do the thoracic spinal nerves pass?
through the intervertebral foramen
What happens to the thoracic spinal nerve once they exist the intervertebral foramen?
They divide into 2 rami: the dorsal (posterior) ramus and a ventral (inferior) ramus
- ventral rami are then called intercostal nerves
What are the branches of intercostal nerve?
- Lateral cutaneous branch
- Terminal, anterior cutaneous branch
- Posterior cutaneous branch
- Muscular branches to the intercostal and anterolateral abdominal muscles for motor innervation
What do the upper six intercostal nerves innervate (1-6)?
Intercostal muscles and overlying skin
What do the lower six intercostal nerves innervate (7-11, subcostal nerve T12)?
Continue anteriorly to enter the anterior abdominal wall supplying the abdominal muscles and overlying skin.
What are the phrenic nerves?
Paired, left and right, nerves formed by the union of the three cervical spinal nerves (C3-C4-C5).
Which nerves innervate the diaphragm?
Left and right phrenic nerves, providing motor innervation
What is the function of the phrenic nerves?
provide motor innervation to the diaphragm (C3, 4, 5, keep the diaphragm alive)
What are the treatment options for a herniated discs?
Rest Ice and Heat Medications Physical therapy Surgery
What are lactiferous products?
Milk or milky lubricating fluid
What are the 4 main components of breasts anatomy?
Lobes
Suspensory ligaments (of Cooper)
Nipple
Lactiferous ducts
Where and what are the ligaments of Cooper
Radial septa in the breasts also called Suspensory ligaments
How many lobes are there in each breast?
15-20
What do lobes contain?
mammary glands
Where can you find the mammary glands?
In the lobes of the breasts/
What is the function of the ligaments of Cooper?
help support the breast
What is mammary duct ectasia?
When a lactiferous duct widens causing the duct walls to thicken
Duct can then become clogged or blocked with lactiferous products
Symptoms: nipple discharge, breast tenderness, breast lump - can also be asymptomatic
More prevalent in perimenopausal women
What muscle lies deep to the breast?
Pectoralis major
Which arteries supply the lateral breast?
Lateral thoracic arteries
Where do lateral thoracic arteries originate from?
Axillary artery
Which arteries supply the medial breast?
Branches of the internal thoracic (mammary) artery proximal to the sternum
What are the 3 groups of lymph nodes into which is done the lymphatic drainage of the breast?
Axillary nodes (laterally) Parasternal nodes (medially) Supraclavicular nodes (superiorly)
What is an Intraductal papilloma?
Beginning as a small benign tumour in a lactiferous duct - typically a small lump proximal to the nipple
It can block a duct completely, which if favourable to infections that can spread rapidly through the lymphatic system
What are some treatment for breast ectasia?
Rest
Pain medication
antibiotics
surgery
Describe the position of the heart
Base is the posterior surface and the apex is directed forward, downward, and to the left. It is about the size of a clenched fist and lies behind the sternum and central part of the thoracic cage
What is covering the heart?
Pericardium, a sac that encloses the heart and the roots of the great vessels entering and leaving it
What are the 4 layers of the pericardium?
Fast People Scare Villains Fibrous layer Parietal layer Serous fluid Visceral layer
Describe the innervation of the heart?
Phrenic nerves provides sensory innervation to the fibrous pericardium and serous parietal pericardium
Left phrenic nerve to innervate left side and right phrenic nerve innervate the right side
One of the first signs of a heart attack can be pain in the shoulder and arm, given what you know about the sensory innervation of the heart and diaphragm, why might chest pain be linked to pain in the shoulder and arm?
Phrenic nerves are formed by the C3, C4, and C5 cervical spinal nerves. Sensory information of the heart travels up the phrenic nerves to the cervical vertebrae. Hence, pain associated with the heart (like heart attack) may be felt in the shoulder and neck; this distribution of perceived pain is known as referred pain.
What is referred pain? give an example
Pain perceived at a location other than the site of the painful stimulus/ origin. Heart attacks often have pain in the left shoulder and arm even if the pain stimulus is in the heart
Describe the anatomy of the right ventricle
Superior wall is smooth and funnel shaped, which forms the infundibulum (or conus arteriosus) which leads to the pulmonary orifice where the pulmonary valve is
Describe the anatomy of the left ventricle?
The superior portion of the left ventricle consists of a smooth-walled vestibule leading to the aortic orifice where the aortic valve is
Describe the anatomy of the aortic valve
3 semilunar cursps and 3 aortic sinuses
Describe the pulmonary valve’s anatomy
3 semilunar cusps
What is hypertrophic cardiomyopathy?
Pathologic structural remodeling of the heart and large arteries such as thickening of the heart musculature. Hypertophy frequently asymmetric
Caused by long-term excessive endurance exercise
Symptoms: shortnessof breath, chest pain during exercise and fainting
What is a mitral valve prolapse?
Condition in which the mitral valve cusps do not close properly because of abnormally long (or short) chordae tendinae or malfunctioning papillary muscles. The mitral valve flops backward into the atrium
What is the overall effect of mitral valve prolapse?
regurgitation of blood back to the atrium
What is the interventricular septum?
Physical barrier between the left and right ventricles made of 2 parts: thick muscular part, thin upper membranous part.
What is the main function of interventricular septum?
Isolate oxygenated blood from deoxygenated blood
In which part of the interventricular septum is a hole likely to form? How would this affect the direction of blood flow? What changes might surrounding structure undergo to compensate?
The membranous part of the septum is the most common site of ventricular septal defects
Because the pressure is higher in the left ventricle than the right, this lesion goes left-to-right (acyanotic) shunting of blood flow
What is the skeleton of the heart?
Dense connective tissue that is the site of attachment of the atrial and ventricular muscles as well as the heart valves
What is calcific aortic stenosis?
Progressive fibro-calcific remodelling and thickening of the aortic valve leaflets that evolve over years to cause severe obstruction to cardiac outflow. As leaflet thickens the aortic valve narrow causing pressure increase in the left ventricle. The left ventricle may also become enlarged
What is pericarditis?
Inflammation of the pericardium. Symptoms include chest pain, shortness of breath and diaphragmatic spasms
What is the path of the aorta out of the heart?
Arching backward and to the left of the vertebral column
What are the 3 main branches off the aorta (in order of proximal to the heart)?
Brachiocephalic
Left common carotid
Left Subclavian
Where does the aortic arch end?
Left subclavian artery
The right common carotid artery and the right subclavian artery originates from what artery?
Brachiocephalic trunk
If a dye is injected into the left ventricle what are, in order, the 4 major vessels it would enter first?
Aorta
brachiocephalic artery
left common carotid artery
left subclavian artery
What is an aortic aneurysm?
An aneurysm is an abnormal widening or ballooning of a part of the aorta due to weakening in the wall of the blood vessel
Which artery gives rise to the right internal thoracic artery?
right subclavian
Which artery gives rise to the left internal thoracic artery?
left subclavian
Name and describe the location of the musculature surrounding the internal thoracic arteries
Anterior and lateral to the internal thoracic arteries are the innermost, internal, and external intercostal muscles.
Anterior to the intercostal muscles and intercostal arteries is the pectoralis major.
Posterior to the internal thoracic arteries is the transversus thoracic muscle.
The diaphragm can be found inferiorly
What are the aortic sinuses?
3 dilations located just above the aortic valve
what does the left and right sinuses give rise to?
the left and right coronary arteries respectively
What does the posterior sinus give rise to?
nothing
Describe the anatomy of the coronary arteries
The right and left coronary arteries anastomoses with each other to form a circle in the coronary sulcus.
The left anterior descending artery passes over the superficially to the heart and in between the ventricles to go anastomose to the loop of the left and right coronary arteries loop
The left coronary artery gives rise to what other arteries?
Circumflex artery
Left anterior descending artery
Why do you think the circle and loop arrangement of coronary circulation is advantageous?
The anastomosis sets up a backup blood supply. If a plaque builds up in a coronary vessel creating a blockage, the blood may reroute using and alternative path in the circle and loop arrangement.
Ensures constant blood supply to the organ
What are pleural recesses?
Potential spaces of the pleural cavity which are not filled with lung tissue during expiration
What are the 2 pleural recesses?
costomediastinal recess
costodiaphragmatic recess
Where are the right and left costomediastinal recesses found?
Anterior thorax, between the costal and mediastinal parietal pleura
Which costomediastinal recess is larger?
Left costomediastinal recess
Which costomediastinal recess overlies the heart?
Left
Where are the costodiaphragmatic recesses?
Between the costal and diaphragmatic pleura, below the inferior part of the lungs.
When are the costodiaphragmatic recesses filled with lung tissue&
Deep inspiration
Where does the fluid of a pleural effusion tend to pool when the patient is standing?
costodiaphragmatic recesses
If fluid is collecting in the costodiaphragmatic recess, how could this affect the function of the lungs?
Excess fluid could limit the expansion of the lungs during inspiration, resulting in difficulty breathing and chest pain
When the pain signals are received by the intercostal nerves, where is the pain typically referred?
thoracic and abdominal wall
What is the parietal pleura’s innervation?
Intercostal nerves (laterally) and phrenic nerves (medially)
Which nerves innervate the parietal pleura medially?
phrenic nerves
which nerves innervate the parietal pleura laterally?
intercostal nerves
What is the visceral pleura’ innervation?
Autonomic innervation, it does not receive sensory innervation
Which pleura does not receive sensory innervation?
visceral
Why do you suspect the visceral pleura is insensitive to pain whereas the parietal pleura is not?
visceral pleura receives pressure from lungs during inspiration
parietal pleura is “outside” and must give signals when full expanded
What is the hilum?
A depression, centered in the medial surface of the lung, where structures enter and exit
What structures make up the root of the lungs?
Pulmonary arteries (superiorly) Pulmonary veins (inferiorly) Bronchi (posteriorly)
What is Pulmonary Arterial Hypertension?
PAH is a condition where a patient has high blood pressure in the pulmonary arteries. The vessels become more stiff, swollen and thick causing scarring, clots and build up of plaque. This impedes blood flow and can compress the adjacent bronchi. Heart muscle must exert a greater force. Prolonged PAH can weaken the heart muscle
Where does the brachiocephalic veins drain?
superior vena cava
Beside the brachiocephalic vein, which other vein is the main tributary of the superior vena cava ?
Azygos vein
Describe the path of the azygos vein
Enters the thorax from the abdomen through the aortic hiatus of the diaphragm. It ascend to the right of the lower thoracic vertebral bodies.
Where do the posterior intercostal vein drain?
Azygos vein
Which veins is considered the highway to the superior vena cava?
azygos vein
What are the tributaries of the azygos vein?
Hemiazygos veins
Accessory hemiazygos veins
right posterior intercostal veins
right bronchial veins
Where are the hemiazygos veins located?
lies to the left of the thoracic vertebrae and drains the left posterior intercostal veins
Where are the accessory hemiazygos veins located?
lies to the left of the thoracic vertebrae, superior to the hemiazygos vein and drains the left posterior intercostal veins
What vessels drain the deoxygenated blood from the lungs
bronchial veins
Which lymphatic duct drains the lymph from the left side of the head, neck, thorax, left upper limb, and all of the structures below the diaphragm?
Thoracic duct
Which lymphatic duct drains the lymph from the right side of the head, neck, thorax and right limb?
Right lymphatic duct
From distal to proximal, list the lymph nodes involved in lymphatic drainage of the lungs
pulmonary lymph nodes bronchopulmonary (hilar) lymph nodes tracheobronchial lymph nodes paratracheal lymph nodes bronchomediastinal trunks
What is sarcoidosis?
Inflammatory disease that causes abnormal masses or nodules to form in the pulmonary bronchopulmonary (hilar) and paratracheal lymph nodes
What arteries supply the lungs with oxygenated blood?
Bronchial arteries
