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