Cardio pre-practical lecture Flashcards
Where does the mediastinum lie?
The mediastinum lies between the left and right pleurae.
- It extends from the sternum in front to the vertebral column behind, and contains all the thoracic organs except the lungs.
- It is divided into 2 parts: a superior part and an inferior part.
What are the 3 regions the inferior part of the mediastinum is divided into?
- It is divided relative to the pericardium.
- The anterior mediastinum is in front of the pericardium.
- The middle mediastinum contains the pericardium and its contents.
- The posterior mediastinum is behind the pericardium.
What are the main contents of the superior mediastinum?
- Glandular plane: thymus
- Venous plane: brachiocephalic vv., SVC
- Visceral plane: trachea, oesophagus
- Lymphatic plane: thoracic duct
What does the anterior mediastinum contain?
- Thymus
- Lymph nodes
- Fat
What are the main contents of the posterior mediastinum?
- Oesophagus & Vagus nerve
- Azygos vein
- Sympathetic trunk
- Thoracic duct
- Descending aorta
- Splanchnic nerve
What are the 2 layers of pericardium?
Fibrous and Serous
What is the serous layer composed of?
- Outer parietal layer
- Inner visceral layer = Epicardium
What is epicardium composed of?
It is composed of endothelial cells and a thin layer of fat and connective tissue.
What cavity is present between parietal and visceral layers?
Pericardial cavity filled with percardial fluid
What surrounds the pericardium?
A fibrous sac
Various anatomical relationships for the pericardium
- Surrounds heart and bases of pulmonary artery and aorta.
- Deep to sternum and anterior chest wall.
- The right phrenic nerve passes to the right of the pericardium.
- The left phrenic nerve passes over the pericardium of the left ventricle.
- Pericardial arteries supply blood to the dorsal portion of the pericardium.
What are the main identification features of the right atrium?
- Openings for IVC, SVC, Coronary sinus
- Interatrial septum
- Fossa ovalis in interatrial septum
- Musculi pectinati
- Tricuspid valve
What are the main identification features of the right ventricle?
- Tricuspid valve: 3 valve cusps, chordae tendineae, papillary muscles
- Trabeculae carneae (contractile fleshy struts)
- Moderator band (Septomarginal trabeculum)
- Opening for pulmonary trunk
- Interventricular septum
What is the purpose of the trabeculae carneae in the right ventricle?
The purpose of the trabeculae carneae is most likely to prevent suction that would occur with a flat surface and thus impair the heart’s ability to pump efficiently. The papillary muscles themselves are just a specialised form of trabeculae carneae.
What does the Moderator band (Septomarginal trabeculum) do in the right ventricle?
It prevents the overballooning of the right ventricle.
What are the main identification features of the left atrium?
- Openings for L+R superior pulmonary veins and L+R inferior pulmonary veins.
- Bicuspid (mitral) valve
- Smooth-walled, small chamber, lying wholly postero-superiorly against oesophagus.
- Forms base of heart
What are the main identification features of the left ventricle?
- Bicuspid (mitral valve), 2 valve cusps, chordae tendineae, papillary muscles x2.
- Trabeculae carneae
- Opening for aorta
- Interventricular septum
- Wall 3x as thick as right ventricular wall.
- Forms apex of the heart
Surface anatomy of heart: Heart
Lies opposite middle 4 thoracic vertebrae (T5-8) in recumbent position.
Surface anatomy of heart: Apex
5th left intercostal space, midclavicular line = left ventricle
Surface anatomy of heart: Base
Wholly posterior = left atrium
Surface anatomy of heart: Right border
SVC and right atrium
Surface anatomy of heart: Left border
Aortic arch and left ventricle
Surface anatomy of heart: Anterior surface
Right atrium (1/4) Right ventricle (2/4) Left ventricle (1/4)
What are the main arteries, veins & lymphatics of trunk and chest wall?
- Internal thoracic artery: gives off anterior intercostal arteries.
- Internal thoracic vein: receives anterior thoracic veins.
- Descending aorta
- Inferior vena cava
- Azygos vein
- Thoracic duct
What are the main arteries of upper limb?
- Subclavian artery
- Axillary artery
- Brachial artery
- Radial artery
- Ulnar artery
Where does the subclavian artery arise from and what does it become?
- It arises from the aortic arch.
- Subclavian becomes axillary at lateral border of 1st rib.