Regional Anatomy of the Mediastinum Flashcards
1
Q
Superior Boundary of the Superior Mediastinum
A
Thoracic Inlet (1st ribs and costal cartilages, jugular notch of manubrium and T1) `
2
Q
Inferior Boundary of the Superior Mediastinum
A
Imaginary Plane which passes through the sternal angle, intervertebral disc of T4/5 and aorticopulmonary window
3
Q
Anterior Boundary of the Superior Mediastinum
A
Manubrium of the Sternum
4
Q
Posterior Boundary of the Superior Mediastinum
A
T1-T4/5
5
Q
Lateral Boundary of the Superior Mediastinum
A
Parietal Pleura
6
Q
Superior Border of the Anterior Mediastinum
A
Imaginary Plane which passes through the sternal angle, intervertebral disc of T4/5 and aorticopulmonary window
7
Q
Inferior Border of the Anterior Mediastinum
A
Thoracic Diaphragm
8
Q
Anterior Border of the Anterior Mediastinum
A
Body of the Sternum
9
Q
Posterior Border of the Anterior Mediastinum
A
Fibrous Pericardium
10
Q
Lateral Border of the Anterior Mediastinum
A
Parietal Pleura
11
Q
Superior Border of the Middle Mediastinum
A
Imaginary Plane which passes through the sternal angle, intervertebral disc of T4/5 and aorticopulmonary window
12
Q
Inferior Border of the Middle Mediastinum
A
Thoracic Diaphragm
13
Q
Anterior Border of the Middle Mediastinum
A
Fibrous Pericardium
14
Q
Posterior Border of the Middle Mediastinum
A
Fibrous Pericardium, tracheal bifurcation, primary bronchi
15
Q
Lateral Border of the Middle Mediastinum
A
Parietal Pleura
16
Q
Superior Border of the Posterior Mediastinum
A
Imaginary Plane which passes through the sternal angle, intervertebral disc of T4/5 and aorticopulmonary window
17
Q
Inferior Border of the Posterior Mediastinum
A
Thoracic Diaphragm
18
Q
Anterior Border of the Posterior Mediastinum
A
Fibrous pericardium, tracheal bifurcation, primary bronchi
19
Q
Posterior Border of the Posterior Mediastinum
A
T4/5 - T12
20
Q
Lateral Border of the Posterior Mediastinum
A
Parietal Pleura
21
Q
Blood Vessel Contents of the Superior Mediastinum
A
Brachiocephalic Veins, Superior Vena Cava (proximal half), Aortic arch and its branches
22
Q
Nervous Tissue Contents of the Superior Mediastinum
A
Phrenic nerves, vagus nerves, left recurrent laryngeal nerve
23
Q
Large Organ Contents of the Superior Mediastinum
A
Trachea and associated lymph nodes, oesophagus, thoracic duct, thymus or its remnant, brachiocephalic lymph nodes
24
Q
Blood Vessel Contents of the Anterior Mediastinum
A
Internal Thoracic Blood Vessels
25
Nervous Tissue Contents of the Anterior Mediastinum
Nil
26
Large Organ Contents of the Anterior Mediastinum
Thymus or its remnant, loose connective tissue (sternopericardial ligaments), parasternal lymph nodes
27
Blood Vessel Contents of the Middle Mediastinum
Great Vessels of the Heart, Pulmonary Arteries and Veins, Arch of the Azygos Vein
28
Nervous Tissue Contents of the Middle Mediastinum
Phrenic Nerves
29
Large Organ Contents of the Middle Mediastinum
Heart, terminal end of the trachea and primary bronchi, Bronchotracheal lymph nodes
30
Blood Vessel Contents of the Posterior Mediastinum
Descending thoracic aorta, azygos, hemiazygos and accessory hemiazygos veins
31
Nervous Tissue Contents of the Posterior Mediastinum
Vagus nerves (contributes to oesophageal nerve plexus)
32
Large Organ Contents of the Posterior Mediastinum
Oesophagus, Thoracic Duct, Posterior mediastinal lymph nodes
33
Artery Definition: Terminal Branch
o An artery end by dividing into different arteries with different names
34
Artery Definition: Continuation
o An artery crosses a certain landmark and so the name changes (the same artery continues named as a different vessel)
35
Artery Definition: Collateral Branch
o ‘Side-branch’
| o Original artery continues past that side-branch
36
Vein Definition: Confluence
o Veins uniting or coming together to form another single (larger) vein, a union
o e.g., Right and Left Brachiocephalic Veins -> Superior Vena Cava
37
Vein Definition: Tributary
o A side vein joins onto a larger vein (a side-branch, however the blood is flowing in a different direction to arteries)
o e.g., Right and left renal veins are tributaries of the inferior vena cava
38
Vein Definition: Continuation
o A vein crosses a certain landmark and so the name changes (the same vein continues named as a different vessel)
39
Major Mediastinal Compartments
The mediastinum is divided into superior and inferior mediastina by an imaginary plane that passes through the sternal angle, aorticopulmonary window and the intervertebral disc between T4/T5 vertebrae
40
What compartments is the Inferior Mediastinum divided into?
o The anterior mediastinum, the middle mediastinum and the posterior mediastinum
41
What are the 4 differing Coronary Anastomoses of the heart?
- Right Dominant
- Left Dominant
- Codominant
- Single Coronary Artery
42
Explain the Right Dominant Coronary Arterial Pattern
o Right Coronary Artery provides the collateral branch of the posterior interventricular artery
o 80-85%
43
Explain the Left Dominant Coronary Arterial Pattern
o Circumflex artery provides the collateral blood flow
| o 10%
44
Explain the Codominant Coronary Arterial Pattern
o Shared blood flow from the right and the left
| o 20%
45
Explain the Single Artery Coronary Arterial Pattern
o Coronary Artery arises from the left and provides all of the blood to the left and right side of the heart
o Only one potential anastomoses
o 0.03-0.07%
46
What are the tributaries of the coronary sinus?
* The great cardiac vein and posterior vein of the left ventricle are tributaries of the left side of the coronary sinus
* The small and middle cardiac veins are tributaries of the right side of the coronary sinus
47
Where is the aorticopulmonary window located?
* Bounded by the inferior surface of aortic arch and the superior surface of the right pulmonary artery
* Located at T4/T5 and forms part of the boundary between superior and inferior mediastina
48
What nerve passes through the aorticopulmonary window?
• Left recurrent laryngeal nerve passes through the aorticopulmonary window
49
Where is the Great Cardiac Vein located and where does it drain into?
- Follows the anterior interventricular artery and circumflex artery
- Drains into the left side of the Coronary Sinus
50
Where is the Small Cardiac Vein located and where does it drain into?
- Accompanies the Right Coronary Artery in the Atrioventricular Groove
- Drains into the to the right of the middle cardiac vein Coronary Sinus
51
Where is the Middle Cardiac Vein located and where does it drain into?
- Begins at the apex and ascends into the posterior interventricular sulcus
- Drains into the right side Coronary Sinus
52
What does the Posterior Vein of the Left Ventricle do and where does it drain into?
- Drains regions of the Left Ventricle that the Great and Middle Veins have not been able to
- Empties into the Coronary Sinus
53
Where is the Apex of the Heart located?
o Apex lies deep to the 5th intercostal space and 7-9 cm to the left of the midline
54
Where is the Base of the Heart Located?
* Base of the heart forms the posterior aspect
| * Faces T6-T9 and is mostly formed by the left atrium and some portion of the right atrium
55
What is the Fossa Ovalis and where is it located?
- Located on the interatrial septum
| - It is the remnant of the foetal foramen ovale
56
What type of blood is found in the Right Superior Pulmonary Vein?
Oxygenated
57
What type of blood is found in the SVC?
Deoxygenated
58
What type of blood is found in the Pulmonary Trunk?
Deoxygenated
59
What type of blood is found in the Ascending Aorta?
Oxygenated
60
What arteries lie in the Interventricular Grooves?
Posterior and Anterior Interventricular Arteries
61
What arteries lie in the Atrioventricular groove?
Right Coronary Artery and Circumflex Artery
62
Origin of the Right Coronary Artery
Collateral Branch of the Ascending Aorta
63
Accompanying Vein to the Right Coronary Artery
Small Cardiac Vein
64
Course of the Right Coronary Artery
Courses to the right in the atrioventricular groove between the right auricle and right ventricle
It then terminates in the posterior wall of the left ventricle
65
Branches of the Right Coronary Artery
It has two collateral branches - Right Marginal Artery and the Posterior Interventricular Artery
66
Origin of the Right Marginal Artery
Collateral Branch of the Right Coronary Artery
67
Course of the Right Marginal Artery
Runs towards the apex of the heart along the right border
68
Origin of the Posterior Interventricular (Descending Artery)
Collateral Branch of the Right Coronary Artery
69
Location of the Posterior Interventricular Artery
Lies in the posterior interventricular sulcus
70
Origin of the Left Coronary Artery
Arises as a collateral branch of the ascending aorta
71
Course of the Left Coronary Artery
Courses between the pulmonary trunk and left auricle to reach the atrioventricular groove
It then terminally divides into the anterior interventricular artery and the circumflex artery
72
Origin of the Anterior Interventricular Artery
Terminal Branch of the Left Coronary Artery
73
Course of the Anterior Interventricular Artery
Courses in the anterior interventricular sulcus towards the apex
74
Origin of the Circumflex Artery
Terminal Branch of the Left Coronary Artery
75
Course of the Circumflex Artery
Continues in the atrioventricular sulcus and courses around the left border of the heart to the posterior surface
It then terminates in the posterior wall of the LV
76
Origin of the Left Marginal Artery
Collateral Branch of the Circumflex Artery
77
Course of the Left Marginal Artery
Descends down the left border of the heart
78
What is the Coronary Sinus and where does it drain into?
- Dilated vein that is located in the posterior atrioventricular sulcus
- All the major cardiac veins drain into it
- Drains into the right atrium
79
Origin of the Phrenic Nerve
Cervical Plexus (derived from the anterior rami of the cervical nerves)
80
Course of the Phrenic Nerve (Together)
Descends lateral to the heart between the fibrous pericardium and the parietal pleura
81
Course of the Right Phrenic Nerve (Individual)
Courses along the right side of the SVC, right atrium and right side of the IVC
82
Course of the Left Phrenic Nerve (Individual)
Courses along the left auricle and left ventricle
83
Termination of the Phrenic Nerve
Each nerve enters the thoracic diaphragm lateral to the pericardium and divides into a number of branches
Branches provide motor supply to the thoracic diaphragm and partial sensory innervation
84
Origin of the Vagus Nerve
Arises from the medulla oblongata within the head as the tenth cranial nerve (CN X)
85
Course of the Right Vagus Nerve
Courses anterior to the brachiocephalic trunk and posterior to the right brachiocephalic vein to the right side of the trachea
Continues posterior to the SVC into the posterior mediastinum
86
Branches of the Right Vagus Nerve
- The right recurrent laryngeal nerve branches off in the root of the neck.
- Therefore, it does not enter the superior mediastinum
87
Course of the Left Vagus Nerve
Courses to the left of the left common carotid artery and posterior to the left brachiocephalic vein
Then continues inferiorly into the posterior mediastinum
88
Branches of the Left Vagus Nerve
Left Recurrent Laryngeal Nerve
Arising anterior to the arch of the aorta, it passes through the aortic pulmonary window and ascends lateral to the trachea towards the neck
89
Thymus variation with age
In a child, the thymus was large and was in both the superior and anterior mediastinum.
In a young adult, there is some regression of the inferior thymic tissue, and it is in the superior mediastinum.
In an elderly individual, a thymic remnant remains within the superior mediastinum (if tissue remains).
90
Azygos Vein
- Receives most of the right posterior intercostal veins
| - Passes into superior mediastinum and drains into ther SVC via the arch of the azygos vein
91
Hemiazygos Vein Course
- Ascends posterioly on the left side of the vertebral column
- Then courses to the right to join the azygos vein at the vertebral level of T9
- Recevies most of the left posterior intercostal veins
92
Hemiazygos Vein Location
Lies mainly posterior to the descending thoracic aorta
93
Accessory Hemiazygos Vein Course
Descends from the left of the superior part of the vertebral column and drains into the azygos vein and sometimes the hemiazygos vein
94
What is an Anastomoses?
- Connection between blood vessels
95
What can cause an anastomoses to form?
Pathology
- High BP, naroowing or inclusion of vessels
- Angiogensis can cause these vessels to form and redirect the blood flow
96
Examples of Anastomoses
- Between the Posterior Interventricular Artery and the Terminal end of the Anterior Interventricular Artery
- Between the Circumflex Artery and the Terminal end of the Right Coronary Artery
97
sternocoastal surface
formed mainly by the right ventricle
98
diaphragmatic surface
formed mainly by the right and left ventricles
99
pulmonary surface
formed mainly by the left ventricle and occupies the cardiac notch of the left lung
100
Fossa ovalis
a depression most evident in the right atrial side of the interatrial septum
101
Termination of trachea
Highly variable
| range between T4/5 to T7
102
Thoracic duct course
courses to the left side opposite T5 and enters the superior mediastinum;
then ascends to the thoracic inlet along the left side of the oesophagus between the left vagus nerve and its left recurrent laryngeal branch, and enters the root of the neck; thoracic duct is crossed anteriorly by the
aortic arch.
