CVS-Mediastinum & Pericardium Flashcards
Where is the sternal angle located?
Between T4 to T5 Vertebrae
What are the borders of superior mediastinum?
Superiorly, first rib and inferiorly, T4 vertebrae
What are the contents of the superior mediastinum?
- Thymus
- Trachea
- Esophagus
- Thoracic duct
- Aortic Arch
- Veins (SVC, Brachiocephalic)
- Nerves (Vagus, phrenic , left recurrent laryngeal)
What is one organ that occupies the superior mediastinum and upper part of the anterior mediastinum?
Thymus
What is the function of Thymus?
- Receives blood from the internal mammary artery / internal thoracic artery
- Plays a role in development and maturation of T cells
The inferior mediastinum can be divided into ____, ____ and _____
Anterior, Middle and Posterior
Where is the location of the middle Mediastinum?
Between anterior and posterior mediastinum
What are the contents of the Middle Mediastinum?
- Heart with pericardium
- SVC
- Ascending aorta
- Pulmonary trunk
- Right and left pulmonary veins
- Right and left phrenic nerves
- Cardiac plexus
- Lymph nodes
The pericardium consists of ____ layers, ______ pericardium and ____ pericardium. The _____ pericardium has ____ layers, the ____ layer and ____ layer.
The pericardium consists of 2 layers, fibrous pericardium and serous pericardium. The serous pericardium has 2 layers, the parietal layer and visceral layer.
Describe the fibrous pericardium
It’s the outermost layer, tough and inelastic. It is bounded to the central tendon of the diaphragm by pericardiophrenic ligament.
Describe the serous pericardium
Parietal layer: Attaches to fibrous pericardium
Visceral layer (epicardium): Attaches to heart wall
Where is pericardial fluid found?
Pericardial space/cavity (10-20ml)
Enables the heart to move and beat in a frictionless environment
Which nerve supplies the fibrous pericardium and parietal layer of the serous pericardium?
Phrenic nerve, sensitive to pain
Which nerve supplies for the visceral layer of serous pericardium?
Branches of the sympathetic and the vagus nerve, insensitive to pain
Explain the course of transverse pericardial sinus.
Located posterior to the ascending aorta and pulmonary trunk, anterior to superior vena cava
Explain the course of oblique pericardial sinus.
Bounded laterally by the pericardial reflections and posteriorly by the pericardium overlying the anterior aspect of the esophagus
What are the structures that pass through the openings of the diaphragm?
IVC (T8)
Esophagus, Vagus nerve (T10)
Aorta, thoracic duct, azgous vein(T12)
(Clinical Anat) What is one procedure performed to drain fluid from the pericardial cavity e.g.cardiac tamponade?
Pericardiocentesis
What are the contents of the posterior mediastinum?
Esophagus
Descending aorta
Azygous vein
Thoracic duct
Sympathetic chain and splanchnic nerves
Explain the course of Esophagus (IMPTT)
- Continues from the pharynx at C6 vertebrae
- Enters the thoracic inlet and lying anterior to the vertebral body and posterior to the trachea
- At the level of sternal angle, crossed by the aortic arch on the left, arch of azygous vein on the right and left bronchus in front
- Crosses down the posterior mediastinum, lies behind the left atrium
- Pierce the diaphragm at T10 level to join the stomach
(IMPTTT) What are the 4 points of esophageal constriction?
- Junction of the esophagus with the pharynx
- Where the esophagus is crossed by the aortic arch
- In the posterior mediastinum where the esophagus is compressed by the left main bronchus
- In the posterior mediastinum at the esophageal hiatus in the diaphragm
Describe the course of descending aorta
- Continuation of arch of aorta and ends as abdominal aorta
- Begins at left side of body of T4 vertebrae but moves midline to lie anterior to lower thoracic vertebrae as it descends in the posterior mediastinum
What are the branches of descending aorta?
- Posterior intercoastal arteries
- Esophageal artery
- Bronchial
- Pericardial
- Subcostal
- Mediastinal
What is the function of the azygous vein?
Drains blood from the posterior wall of the thorax and abdomen, recieves posterior intercoastal, esophageal, bronchial and mediastinal veins.
Describe the course of azygous vein
Ascends in the posterior mediastinum through the aortic opening passing close to the inferior T8 vertebrae on the right and arches on the superior aspect of the root of the right lung to join SVC
There are ___ posterior intercoastal veins and ___ subcoastal vein on each side.
11, 1
Where do the posterior intercoastal veins drain to?
1st posterior intercostal vein on each side drain into brachiocephalic vein
Remaining right intercostal veins drain into azygous vein
Remaining left intercostal veins drain into azygous veins via hemiazygous vein
Explain the course of thoracic duct
- Originates from the cisterna chyli in the abdomen as dilated sac and ascend through the aorta opening in the diaphragm
- In the posterior mediastinum, it lies between the descending aorta and azygous vein
- At T4/T5 vertebrae level, it crosses to the left and posterior to the esophagous and ascends into the superior medistinum
- Empty into the venous system near the venous angle
Where do the splanchnic nerve supply?
Abdominal organs inferior to the diaphragm
