Anatomy Flashcards
Which ribs are the true vertebrosternal ribs?
ribs 1-7
Which ribs are the false (vertebrochondral) ribs?
ribs 8-10
Which ribs are the floating ribs?
ribs 11-12
What is the difference between vertebrosternal, vertebrochondral and floating ribs?
true ribs are bound to the sternum with costal cartilage at the costochondral joint
the costal cartilage of false ribs flows into costal margins that form the infrasternal (subcostal) angle. They do not articulate with the sternum
floating ribs have no costal cartilage and are only posteriorly attached to the vertbrae
What is the order of the intercostal neurovascular bundles (superior to inferior)?
V-A-N
[posterior] intercostal vein
[posterior] intercostal artery
intercostal nerve
where do the intercostal neurovascular bundles run on a rib (2)?
- beneath the inferior rim of the rib
- in the costal groove of the rib
where are blood, pus or pleural effusions usual found in the lungs (2)?
In the costodiaphragmatic and costomediastinal recesses
What is a pleural effusion
an abnormal collection of fluid in a pleural space.
*can be caused by cancer
When blood, pus or a pleural effusions collects in a costodiaphragmatic or costomedistinal recess, what symptoms are seen in the patient?
How is it treated?
dyspnea: difficulty breathing or shortness of breath
treatment: thoracentesis
Generally, how is a thoracentesis performed (2 steps)?
- locate collection on a CT/ultrasound
- tap the effusion with a needle (IOT draw the fluid out of the chest cavity/pleural space)
- patient will breath easier
When the pleural space is broken, air flows _1_ the chest wound instead of through the _2_. Why does this happen?
- into
- lungs
This happenes because of the negative and positive pressures generated in the ventilatory cycle
In exhalation, _1*_ in the lungs _2(increases/decrease), while _3*_ and _4*_ _5(increases/decrease).
*intrapleural pressures, tidal volume, intrapulmonary pressures
- tidal volume
- decreases
3-4. intrapulmonary/intrapleural pressures
- increases
what is a pneumothorax?
what is the effect of a pneumothorax?
air fills the pleural space between the lungs and chest wall
the lung collapses
what causes a sucking chest wound?
how do you treat a sucking chest wound (2 steps)?
pneumothorax
- treatment:
1. insert an emergency chest tube
2. place it on negative pressure (IOT re-expand the collapsed lung and drain blood)
IOT treat a sucking chest wound, insert a __1__ and place it on _2 (+/-)_ pressure IOT _3_ the collapsed lung and to _4_ the blood.
- chest tube
- negative
- re-expand
- drain
a chest tube is inserted through the layers of the _1_ space but close to the _2_ of the rib.
- intercostal
- superior margin
When in the field, how can you provide negative pressure for a chest tube?
- in the field, seal the end of the tube by tying it or taping it with a rubber glove
- if on the ward, place the end of the tube under water in a bottle that is below the level of the patient (ex. put the bottle on floor next to patient)
what are the muscles of the thoracic wall?
external intercostal
internal intercostal
innermost intercostal
transverse thoracis
diaphragm
How do external intercostal muscles attach to ribs? What is their main action?
They originate from the inferior border of a rib and insert on the superior border of the next rib. The point diagonally towards the center of the thorax/abdomen.
The action is to elevate ribs during forced inspiration
what is the attachment of the internal and innermost intercostal muscles?
what is their action?
- originate from the inferior border of ribs and insert on the superior border of the next rib. point away from the midline.
- the action during forced respiration is as follows:
- interosseous part: depresses ribs
- interchondral part: elevates ribs
where does the transversus thoracis muscle originate and attach?
what is its action?
what is it innervated by?
- the transversus thoracis muscle originates on the **posterior surface of the lower sternum ** and inserts on the internal surfaces of costal cartilages 2-6
- the action of the transversus thoracis muscle is to weakly depress the ribs
- it is innervated by the intercostal nerves
the internal thoracic arteries arise from which arteries? Where do they drain?
arise form the subclavian arteries. drain to the brachiocephalic vein.
At which thoracic vertebral levels do the inferior vena cava, esophagus and aorta penetrate the diaphragm?
“8-10-12”
IVC penetrates at T8
Esophagus penetrates at T10
Aorta at T12
How does the diaphragm contract? What is the result
Its domes are pulled inferiorly. As a result, the domes are flattened and abdominal viscera are pushed inferiorly therefore increasing the volume of the thoracic cavity and allowing more air into the lungs.
*also, blood in the IVC is pushed to the heart when the diaphragm contracts