Mediastinum Flashcards
Mediastinum
Space between the pleural cavities occupying the center of the thoracic cavity
Boundaries for the mediastinum
Anterior Posterior Superior Inferior Lateral
Anterior boundary of mediastinum
Sternum
Posterior boundary of mediastinum
Thoracic vertebrae
Superior boundary of the mediastinum
Thoracic inlet
Inferior boundary of mediastinum
Diaphragm
Lateral border of the mediastinum
Pleura
Divisions of the mediastinum
Superior
Inferior
Portions of the inferior mediastinum division
Anterior mediastinum
Middle mediastinum
Posterior mediastinum
Contents of middle mediastinum (12)
Pericardium and heart Phrenic nerves, cardiac plexus Pulmonary trunk bifurcation Right and left pulmonary arteries Right and left pulmonary veins Ascending aorta Superior vena cava Inferior vena cava Azygos vein Tracheal bifurcation Right and left bronchi Lymph nodes
Contents of superior mediastinum
Thymic remnants Trachea Esophagus Brachiocephalic veins Superior vena cava Aortic arch Brachiocephalic artery Left common carotid artery Left subclavian artery Internal thoracic vessels Vagus nerve Phrenic nerve Thoracic duct Lymph nodes Ligamentum arteriosum
Thymus extends:
Inferiorly into the anterior mediastinum
Most prominent in children
Arterial supply to the thymus
Inferior thyroid artery (anterior part of thymus)
Internal thoracic artery
Venous drainage of the thymus
Thymic vein- drains to the left brachiocephalic vein
Internal thoracic vein
Tributaries to the brachiocephalic veins
Subclavian vein Internal jugular vein Vertebral veins Inferior thyroid vein Internal thoracic vein Left superior intercostal vein
Superior vena cava is formed by
Two brachiocephalic veins
Superior vena cava begins and ends at:
Begins at right 1st CC
Ends behind right 3rd CC
Tributaries of superior vena cava
Right brachiocephalic vein Left brachiocephalic vein Azygos veins Pericardial veins Mediastinal veins
Arch of the aorta lies:
Behind the manubrium stern I
Arch of the aorta begins and ends:
Begins at the level of sternal angle
Ends at level of sternal angle
Arch of aorta has how many branches?
3
Brachiocephalic artery branches into
Right subclavian artery
Right common carotid artery
Three branches of the aortic arch
Brachiocephalic artery
Left common carotid artery
Left subclavian artery
Contents of posterior mediastinum (6)
Esophagus Thoracic aorta Azygos and hemiazygos veins Thoracic duct, lymph nodes Sympathetic trunks Vagus nerves
Length of esophagus
Approx 10 inches long
Esophagus is lined with what epithelium
Stratified squamous
Where does the esophagus begin
At the level of C6, from the cricoid cartilage
Where does the esophagus pierce the diaphragm
At level T10
Sites of esophageal constriction (4)
At the junction of the pharynx and the esophagus
Where the esophagus is crossed by the arch of aorta
Where the esophagus is compressed by the left main bronchus
At the esophageal opening of the diaphragm
Arterial supply of the esophagus
Upper 1/3: Inferior thyroid artery
Middle 1/3: thoracic aorta
Lower 1/3: left gastric artery
Inferior thyroid artery derived from
Thyrocervical trunk
Subclavian artery
Left gastric artery derives from
Celiac trunk
Venous drainage of the esophagus
Upper 1/3: inferior thyroid vein
Middle 1/3: Azygos vein
Lower 1/3: Left gastric vein
Left gastric vein drains into
Portal vein
Lymphatic drainage of the esophagus
Upper 1/3: Deep cervical nodes
Middle 1/3: Mediastinal nodes
Lower 1/3: Left gastric nodes
Innervation of the esophagus
Vagus nerves
(Left forms anterior plexus, right forms posterior plexus)
Sympathetic innervation:
Cervical trunk
Thoracic trunk
Sensation of the esophagus
General sensation: Parasympathetic
Pain: Sympathetic
Parts of the aorta
Ascending aorta
Arch of aorta
Thoracic aorta
Abdominal aorta
Thoracic aorta begins and ends:
Begins at level of sternal angle
Ends at vertebral level of T12 (aortic opening)
Thoracic aorta becomes continuous with
Abdominal aorta
Where does the thoracic aorta lie?
Posterior mediastinum
Branches of the thoracic aorta (7)
Posterior intercostal arteries (lower 9) Subcostal arteries Superior phrenic arteries Pericardial branches Esophageal branches Bronchial branches Mediastinal branches
What 2 veins join to form the azygos vein?
ascending lumbar and subcostal veins
Azygos vein passes through:
Aortic opening at T12
Where does the azygos vein ascend?
In the posterior mediastinum
Azygos vein arches over:
The right bronchus (T4) to drain into SVC
Tributaries of azygos vein (9)
Ascending lumbar vein Right subcostal vein Hemiazygos veins (major tributary) Accessory hemiazygos veins Mediastinal veins Esophagus veins Right bronchial veins Pericardial veins
Longest lymphatic channel
Thoracic duct
Where does thoracic duct begin and end
Begins At cisterns chyli (T12)
Ends at the junction of the left internal jugular and subclavian veins
Thoracic duct passes through
Aortic opening
Tributaries of the thoracic duct (3)
Left jugular lymph trunk
Left subclavian lymph trunk
Left bronchomediastinal lymph trunk
Right lymphatic duct
Right jugular lymph trunk
Right subclavian lymph trunk
Right bronchomediastinal lymph trunk
Contents of the anterior mediastinum
Thymic remnants
Lymph nodes