Anatomy 1 Flashcards
(25 cards)
The partition between the right and left pleural sacs
Mediastinum
The mediastinum includes
All the structures which lie in the intermediate compartments of the thoracic cavity.
Boundaries of mediastinum:
Ant-
Post-
Super-
Infer-
Ant- Sternum
Post- Vertebral column, thoracic vertebrae
Super- Thoracic inlet
Infer- Diaphragm
Division of the mediastinum
It is divided by a horizontal plane extending from the sternal angle to the 4th thoracic vertebra, divided into:-
1) Superior mediastinum, above the plane.
2) Inferior mediastinum, below the plane and is subdivided into:-
- Anterior mediastinum
(In front of the pericardium)
- Middle mediastinum
(Contains heart and pericardium)
- Posterior mediastinum
(Behind the pericardium)
Boundaries of the SUPERIOR mediastinum:-
Superior-
Inferior-
Anterior-
Posterior-
On each side-
Superior- Thoracic inlet
Inferior- Imaginary plane from sternal angle to disc t4 & t5
Anterior- Manubrium sterni
Posterior- Upper 4 thoracic vertebrae
On each side- Pleura
The most anterior structure within the superior mediastinum
Thymus gland
Location of the thymus gland
Located on the posterior surface of the sternum extending into the anterior mediastinum
In the superior mediastinum there are 3 tubes
1) Trachea
2) Esophagus
3) Thoracic duct
The trachea bifurcates into…
The primary bronchi posterior to the ascending aorta at the level of the sternal angle.
In the superior mediastinum, the thoracic duct passes to…
The LEFT of the esophagus on its path to the junction of the left internal jugular and subclavian veins.
There are 4 arteries in the superior mediastinum
The arch of the aorta and it’s 3 branches…
1- Brachiocephalic artery
2- Left common carotid artery
3- Left subclavian artery
Origin of the arch of aorta
Continuation of the ascending aorta, at the upper border of the 2nd costal rib.
End of arch of aorta
Continues as descending aorta, opposite lower border of t4.
The brachiocephalic artery divides into…
Right common carotid artery and right subclavian artery
Aortic aneurysm
The dilatation of the aorta compresses the contents of the superior mediastinum causing mediastinal syndrome.
Define mediastinal syndrome
Compression of the mediastinum by a tumor, inflammatory mass, lymph nodes, or retrosternal goiter.
The compression of the mediastinum in mediastinal syndrome leads to…
1) Dyspnea
2) Dysphagia
3) Hoarseness of the voice
(Due to compression of the left recurrent laryngeal nerve)
4) Ischemia
(Compression of aorta)
There are 3 veins in the superior mediastinum
Right brachiocephalic vein
Left brachiocephalic vein
Superior vena cava
Formation of brachiocephalic veins
By the union of internal jugular and subclavian veins, behind the medial end of the clavicle.
End of brachiocephalic veins
Both veins unite to form the superior vena cava
The right brachiocephalic vein is
Shorter and has a vertical course
The left brachiocephalic vein is
Longer and has an oblique course related anteriorly to manubrium sterni and posteriorly to branches of arch of aorta.
