EXAM3_G23_Superior_Posterior_Mediastinum Flashcards
Order of 6 major structures from Anterior to Posterior of the superior mediastinum
This should be your mental checklist:
TGGTEL
- Thymus
- Great Veins
- Great Arteries
- Trachea
- Esophagus
- Lymphatics (mainly posterior)
What arteries supplies blood to the thymus?
- Internal thoracic artery
2. Anterior intercostal Arteries
Where does blood drain from the thymus?
- Left brachiocephalic vein
- Internal thoracic vein
- Inferior thyroid vein
What does lymph from thymus drain to?
- Parasternal nodes
- Brachiocephalic nodes
- Tracheobronchial nodes
What drains lymph into the thymus?
NOTHING! - no afferent lymphatics for thymus
What drains blood from head neck and upper limbs into the right atrium?
Brachiocephalic Veins (LEFT IS LONGER) -
What is the point called where the jugular vein and subclavian vein combine to form the LR brachiocephalic vein
LR Venous Angles
Blood from all structures superior to diaphragm (except heart and lungs) drain into the ?
SUPERIOR VENA CAVA
The Transverse thoracic plane is a landmark for what feature of the heart?
Base of arch of the Aorta
ascending and descending shows at this level on radiograph
In an AP radiograph- At the transverse thoracic plane- the aorta ascends anterior to the ________ and ____. It arches over and posterior to the _______. and Descends ___ of midline
ascends anterior to right pulmonary artery and tracheal bifurcation.
Arches over and posterior to root of the lung and descends LEFT of midline
What two landmarks that your looking at the Descending aorta on radiograph (at transverse thoracic plane)
- Left midline deviation
2. Posterior to root of the lung
Blood bypasses the ______ circuit in a fetus via a shunt called the_____ which becomes the ____ _______ after birth. This forms between the ______ and the _____,
Pulmonary Circuit via the Ductus Arteriosus
which becomes the ligamentum arteriosum which forms between the LPA and Aortic Arch
The transverse thoracic plane is a landmark for what feature of the trachea?
Ends at the transverse thoracic plane by branching into right and left main bronchi
What are two Keys that define you’re looking at the Trachea at the TTP level of a radiograph?
- widening/bifurcation
- slight right deviation
- anterior to esophagus
- posterior to aortic branches
Vagus and phrenic nerve which is anterior/posterior to ROL?
VP- Posterior ROL is Vagus (with Left recurrent laryngeal n)
AP- anterior ROL is PHRENIC
LEFT recurrent laryngeal nerve located? and innervates?
Hooks medially under AORTIC ARCH superiorly to innervate laryngeal muscles
RIGHT recurrent laryngeal nerve located?
Hooks posteriorly under right SUBCLAVIAN artery superiorly to innervate laryngeal muscles
5 Components of the Posterior mediastinum
- Thoracic Aorta
- Thoracic Duct
- Azygos system of veins
- Esophagus
- Nerves
What are the Vertebral levels of the posterior mediastinum?
Posterior (means inferior mediastinum) Under TTP-
T5 - T12
What are the branches of the Thoracic Aorta?
- Bronchial aa
- Esophageal aa (ribs 2-5)
- Posterior Intercostal aa (ribs 3-11)- anast w/ Ant Intcstls
- Subcostal aa. 1 pair inferior to rib 12
Esophageal aa are found at what rib levels of the thoracic aorta?
ribs 2-5 (unpaired)
Posterior intercostal arteries (9 pairs) course inferior to ribs ? What do they anastomose with?
3-11
anastomose with Anterior intercostal aa
Subcostal aa (1 pair) run inferior to rib ?
12
Esophagus runs ____ of the thoracic aorta
Right
What are the three points of compression of the esophagus?
- Cervical constriction
- Thoracic constriction (Aorta/Trachea)
- Diaphragmatic constriction
What drains into the azygous veins?
What is a unique feature about these veins?
Thoraco-abdominal walls
Mediastinal structures
- NO VALVES
-Communicates with vertebral venous plexuses
Azygous veins can communicate with the vertebral venous plexus. This is one pathway for cancer to spread from where to where??
From thoracic wall & Viscera to the CNS
Azygous vein Transverses along the ____ side of the thoracic vertebrae and provides collateral pathway between the ____ and _____ and joints the SVC at the ______.
RIGHT side of vertebrae
SVC & IVC and joins SVC at TTP.
Hemiazygous vein courses on ___ side of thoracic vertebrae and usually at ____ turns medially to drain into the _____vein.
Left at T9, drains into Azygous vein
Acessory hemiazygous vein courses ____ of thoracic ver. usually at ____ vert level turns medially and drains into the ____. vein . sometimes it connects to ______.
Left of TV, usually at T8 turns medial drains into Azygous
Sometimes connects to hemiazygous v.
Thoracic duct courses superiorly on the ____ side of the thoracic vertebrae and switches to the ___ side at ___ to ___ vert levels
Right side, switches to left side at t4-t6 vertebral levels
The thoracic duct returns lymph to venous circulation where?
at Left venous angle
Posterior Mediastinal Lymph nodes filter lymph from 4 places?
- esophagus
- posterior pericardium
- diaphragm
- posterior intercostal space
Esophagus, posterior pericardium, diaphragm, and posterior intercostal space drain their lymph into?
Posterior mediastinal lymph nodes
Sympathetic trunks
Bilateral chain of paravertebral ganglia
Sympathetic trunks supply sympathetic innervation to viscera of body wall & cavities (sweat glands, arector pili).
the thoracic portion gives rise to ____. nerves
abdominopelvic splanchnic nn.
White/Gray RC- >ParaVert ganglion- >abdominopelvic splanchnic nn
Abdominopelvic splanchnic nerves- where do they arise? what do they innervate?
Three bilateral pairs of abdominopelvic splanchnic nerves originate in the thorax and supply sympathetic innervation to viscera inferior of the diaphragm.
Vert level for Greater splanchnic Nerves
T5-T9
Vert level for Lesser splanchnic Nerves
T10-T11
Vert level for Least splanchnic nerves
T12
4 contents of anterior mediastinum
- Adipose/thymus
- Internal thoracic aa/vv
- Anterior intercostal aa/vv
- Parasternal nodes
