The Heart Flashcards
What does the heart rest on?
The Diaphragm
How much of the heart lies to the left of the midline?
2/3
Where is the heart located?
In the mediastinum
What is contained within the mediastinum?
The heart, ascending aorta, superior vena cava, the trachea, main stem bronchi, and the esophagus
What will make the heart appear larger on a radiograph?
AP projection
Short SID
LPO position
Hold on expiration
How do you find the cardio thoracic ratio?
You divide the size of the heart at its widest point against the size of the thoracic cage at its widest point
What is a normal cardio thoracic ratio?
The heart should be less then 50% of the thoracic cage space
What do you do if the cardio thoracic ratio is above 50%?
You perform a lateral
How do you identify an enlarged heart in a lateral projection?
More then 50% is resting against the body of the sternum
What is the pericardium and what is its purpose?
It is the membrane that surrounds the heart and its purpose it to protect and hold the heart in place within the mediastinum while providing sufficient movement during vigorous contractions
What are the 2 layers of the pericardium?
1) Fibrous pericardium
2) Serous pericardium
What does the fibrous pericardium attach to?
It attaches to the adventitial layers of the aorta, pulmonary trunk, and superior vena cava
What are the 2 layers of the serous pericardium?
1) The parietal layer
Space full of pericardial fluid
2) The visceral layer (which becomes the outer layer of the heart
What are the 3 layers of the heart wall?
1) The epicardium (also called the visceral layer of the serous pericardium)
2) The myocardium (95% of the heart wall and made of striated muscle)
3) The endocardium (smooth inner layer with an epithelial lining)
How is the heart situated in the body?
The heart is rotated towards the left and tipped backwards
What heart structures are apart of the base of the heart?
Superior vena cava, inferior vena cava, ascending aorta and pulmonary trunk/arteries
Will you ever see the left atrium in an AP or PA projection?
No you will see the left auricle which sits on top of the left atrium
What does the coronary sinus do?
It drains deoxygenated blood from the myocardium and and returns it to the left atrium
What is the purpose of the auricles?
An ear like appendage that serves to increase the amount of blood held in the atrium
Where does the right atrium receive blood from?
The SVC, IVS, and the coronary sinus
What is the fossa ovalis
It is what remains when the foramen Ovale closes off which is how blood travels between the ventricle as an infant
Where does the SVC bring blood from?
Deoxygenated blood from the upper extremities, head and neck.
Where does the IVC bring blood from?
Deoxygenated blood from everywhere except the upper extremities, head and neck
What prevents the valves from flipping up during contraction?
The chordae tendineae
