Thorax Flashcards
What forms the thoracic cage?
12 pairs of ribs
sternum
costal cartilages
12 thoracic vertebrae
What forms the thoracic wall?
cage + muscles and fascia
What is the function of the thoracic wall?
1) Protect thoracic cavity and upper abdominal
2) respiration
3) attachment for skin, fascia, muslces of neck, thorax, upper limbs, abdomen, back
What are the boundaries of the thoracic wall?
anterior: sternum, costal cartilages
laterally- ribs
posteriorly- thoracic vertebrae and IV discs
What are the special features of the thoracic vertebrae?
1) long, inferiorly angled spinous processes
2) costal facets on the transverse processes where ribs articulate (except last 2 or 3)
3) 2 demifacets on bodies T2-T9 for articulation with other ribs
- superior articulates with head of same rib number
- inferior articulates with head of inferior (higher number)
What does the inferior articular facet on the rib head articulate with?
vertebra of same number as rib
What does the superior articular facet of the rib head articulate with?
vertebra above (lower number)
What does the rib tubercle articulate with?
same number vertebra
attachment site for costotranserse ligaments
in neck
What are the true ribs?
1st-7th
What are the false ribs?
8th- 10th
What are the floating ribs?
11th and 12th
What are the atypical features of the first rib?
1) scalene tubercle
2) single facet for articulation with only the T1 vertebra
What are the atypical features of the 2nd rib?
tubercle for origin of serratus anterior muscle
What are the atyipcal features of the 10th rib?
only one faet for articulation with only one vertebra
What are the atypical features of the 11th and 12th ribs?
no necks or tubercles
free floating
articulate with only one vertebra
Where is the manubrium of the sternum?
level of T3 and T4 with jugular notch
Where is the body of the sternum?
T5-T9
Where is the xiphoid process of the sternum?
T10
Where can the jugular (suprasternal) notch be felt?
palpated at T2 level
Where can the sternal angle be felt?
palpated at the T4 level
What are the boundaries of the superior thoracic aperture?
T1
1st ribs and cartilage
superior border of manubrium
What passes through the superior thoracic aperture?
1 trachea
2 esophagus
3 nerves and blood vessels for head neck and upper extremities
What binds the inferior thoracic aperture?
T12 11th and 12th rib pairs costal cartilages of ribs 7-10 xiphisternal joint closed by diaphragm
What are the 3 openings to the inferior thoracic aperture?
- inferior vena cava hiatus (T8)
- esophageal hiatus (T10)
- aortic hiatus (T12)
What are the four intercostal muscles of the thoracic cage?
external intercostal- raise ribs inspiration
internal intercostal - lowers ribs exspiration
innermost intercostal- raise ribs inspiration
transversus thoracis- w/ sternum
Where do the thoracic fibers run?
anterior superior
posterior inferior
What innervates the diaphragm?
phrenic nerve C3-5 cerivical plexus
Attached to: xiphoid process, lower 6 intercostal cartilages and L1-L3 vertebrae and converge into central tendon
functino: draw central tendn down and forward during inspiration
What are the 3 major openings of the diaphragm>
1) inferior vena cava (T8)
2) esophagus (T10)
3. Aorta (T12)
I ate ten eggs at noon
How does the thoracic cage move during breathing?
vertical diameter increases during inspiration as diaphragm decends
diaphragm ascent during expiration to return to size
transverse diameter = increases slightly when intercostals contract= BUCKET HANDLE motion
Anteroposterior diameter= movemnt of ribs 2-6 and sternal ends of ribs raise = PUMP HANDLE motion
sternum moves forward as lift chest= scalene and SCM can help with respiration to bring in 02 if struggling
What is the neurovasculature of the throcic wall?
Intercostal vein
intercostal artery
interscostal nerve
nerve most exposed because most superficial
dont stick needed between ribs on up angle
What is the blood supply to the posterior wall of the thoracic cage?
posterior intercostals
branches of aorta and costocervical trunk
What is the blood supply to the anterior wall if the thoracic cage?
anterior intercostals
branches of internal thoracic and musculophrenic arteries
Where do the intercostal veins drain?
azygos (right) vein then hemizygos veins (left)
deep and run opposite arterys
What is the nerve supply to the thoracic wall?
intercostal muscles innervated by ventral rami of thoracic nerves
What are the important dermatomes?
C4 = clavical and jugular notch (supraclavicular) T2= sternal angle T4 = nipples
dermatomes usually drop 2 levels from posterior to anterior (T2 front = T4 back)
What are the 2 divisons of the mediastinum?
superior mediastinum and inferior mediastinum
What is in the superior mediastinum?
above sternal angle
1) thymus
2) brachiocephalic veins and superior vena cava
3) phrenic and vagus nerve (recurrent laryengeal)
4) aortic arch and branches
5) trachea
6) esophageous
7) thoracic duct
What is the in the inferior mediastinum?
inferior to sternal angle superior to diaphragm
anterior mediastinum = thymus and sternopericardial ligs
middle mediastinum= pericardial cavity/heart, great
vessels, phrenic m, roots of lung
posterior mediastium= esophagous, descending aorta branches, azygos veins, thoracic duct, sympathetic chair and splanchnic nerve
What is the most superficial structure against the ribs?
branches of interal thoracic vessels
in ant mediastinum
Where is the aortic arch and branches?
superior mediastinum
brachiocephalic trunk
left common cartotid a
left subclavian a
Where is the phrenic nerve?
on top of lungs
Where is the vagus nerve?
with aortic arch behind heart- plexus
Where is the recurrent largyngeal nerve?
in tracheoesophageal groove
How do the lungs appear in a CT?
black hole = air
