Mediastinum Flashcards
central compartment of thoracic cavity between the pulmonary cavities
Mediastinum
Mediastinum lined by ____ on both sides
mediastinal (parietal) pleura
(Superior mediastinum) – bounded superiorly by:
superior thoracic aperture
(Superior mediastinum) – bounded inferiorly by
transverse thoracic plane (level of sternal angle to T4/T5 vertebrae junction)
(Superior mediastinum) –Bounded anteriorly by
manubrium
(Superior mediastinum) – bounded posteriorly by
vertebral bodies of T1-T4
Inferior mediastinum – between ____ and diaphragm
transverse thoracic plane
Inferior mediastinum – bounded
anteriorly by
body of sternum
Inferior mediastinum- bounded posteriorly by
lower 8 thoracic vertebral bodies
Inferior mediastinum–divided into three parts:
anterior, middle, and posterior
(Name the location)
Contains from anterior to posterior:
* (Remnants of)thymus
*Great vessels (with brachiocephalic veins and SVC anterior to arch of aorta)
* Vagus and phrenic nerves, trachea, esophagus
* Thoracic duct and lymphatics
Superior Mediastinum
Inferior mediastinum Parts–(remnants of) thymus
anterior part
(Inferior mediastinum Parts)–location of the pericardium and heart proper
middle part
(Inferior mediastinum Parts)–region behind the heart containing the thoracic aorta, esophagus, thoracic duct, azygos system of veins, sympathetic chain
posterior part
– contains no major structures
Otherwise has:
–loose CT
–fat
–some lymphatic vessels
–lymph nodes
–branches of the internal thoracic vessels
Anterior mediastinum
contains neural, vascular, and respiratory structures passing from the adjacent regions of the neck and abdomen (via the inferior mediastinum
Superior mediastinum
In children, both the anterior and superior mediastinum contain the ____
thymus
–Small, irregular shaped organ in the upper chest that produces and matures immune cells, including T-cells or T lymphocytes
–Primary Lymphoid Organ
thymus
After puberty, the thymus undergoes gradual involution and is largely replaced by ___
fat
Where is the thymus located?
the lower part of the neck and the superior and anterior parts of the mediastinum
The Thymus lies posterior to the ____ and anterior to the left brachiocephalic vein and pericardium (in children)
manubrium
The Thymus Lies posterior to the manubrium and anterior to the ___ and pericardium (in children)
left brachiocephalic vein
The great systemic blood vessels coming in and out of the heart lie within the ____ and their main branches arise before passing through the ____
superior mediastinum. superior thoracic aperture.
Right and left brachiocephalic veins will join to form ____
superior vena cava
Pulmonary trunk will exit right ventricle and split into:
right and left pulmonary arteries
Ascending aorta will leave ___and has three branches along the aortic arch
left ventricle
3 branches of the ascending aorta:
brachiocephalic, L. common carotid, and L. subclavian arteries
Superior vena cava returns blood from all structures superior to the diaphragm, except:
the heart and lungs
What vein will drain blood from thoracic wall into SVC?
Azygous vein
Superior Vena Cava lies in right side of the ____, anterolateral to the trachea and posterolateral to the ____
superior mediastinum; ascending aorta
Terminal half of Superior Vena Cava is in the:
middle mediastinum
Pulmonary trunk: Exits from the ___ to bring oxygen poor blood to the lungs
right ventricle
Pulmonary Trunk: Exits from the right ventricle to bring ___ blood to the lungs
oxygen poor
Pulmonary Trunk: Initially ___ to the aorta, then moves ___
anterior; medially and posteriorly
Pulmonary Trunk bifurcates into the:
right and left pulmonary arteries
Small fibrous cord that passes from the root of the left pulmonary artery to the inferior surface of the arch of the aorta
Ligamentum Arteriosum
Remnant of the fetal ductus arteriosus
Ligamentum Arteriosum
fetal ductus arteriosus–This worked to shunt blood from the ___ to the ___, bypassing the nonfunctional lungs
pulmonary trunk; aorta
Failure of the ductus arteriosus to close is called a:
patent ductus arteriosus (PDA)
patent ductus arteriosus (PDA) can lead to
mixing of blood from aorta (oxy) in pulmonary artery (deoxy)
T/F: The path of the right and left vagus nerves are different
True
runs parallel to the trachea and passes posteriorly to the superior vena cava and the right primary bronchus.
right vagus nerve
enters the superior mediastinum between the left common carotid and the left subclavian arteries. It descends anteriorly to the aortic arch, before travelling posterior to the left bronchus
left vagus nerve
The right recurrent laryngeal hooks around the right subclavian artery and ascends between the trachea & esophagus to supply the ___
larynx
The right recurrent laryngeal hooks around the ___ and ascends between the trachea & esophagus to supply the larynx
right subclavian artery
What nerve supplies the larynx?
Right recurrent laryngeal
The left recurrent laryngeal nerve arises from the ___ as it passes the aortic arch.
left vagus nerve
The left recurrent laryngeal nerve loops under the arch, to the left of ___, before continuing its journey to the larynx in the tracheal- esophageal groove.
ligamentum arteriosum
The left recurrent laryngeal nerve loops under the arch, to the left of ligamentum arteriosum, before continuing its journey to the larynx in the ___
tracheal- esophageal groove.
Vagus is ____ to the internal jugular vein; Phrenic is ___ to the internal jugular vein
medial; lateral
Right recurrent laryngeal n. (passes under subclavian a. and in close contact to ___ of lung)
apex
Tumors of the left or right lung, dilations of aortic arch or pulmonary trunk, esophageal cancer, and tracheal cancer can compress the ___ causing hoarseness
recurrent laryngeal nerve
What can compression of the recurrent laryngeal nerve cause?
hoarseness
T/F: the right recurrent laryngeal nerve enters the mediastinum
false (stays outside); loops around right subclavian artery
Right and left vagus nerves give off ____ branches that contribute to the cardiac and pulmonary plexuses
parasympathetic
Right and left vagus nerves give off parasympathetic branches that contribute to the ____
cardiac and pulmonary plexuses
As the vagus nerves pass behind the main bronchi, they converge on the esophagus and form the:
esophageal plexus
Just superior to the diaphragm, the plexus gives rise to two vagal trunks:
the anterior and posterior vagal trunk
Passes along anterior surface of the anterior scalene muscle in the neck
Phrenic Nerve (C3-C5)
Phrenic Nerve (C3-C5): Enters the mediastinum _____ to the great vessels
lateral
Phrenic Nerve (C3-C5): Descend anteriorly into the ____, passing anterior to the root of the lungs
middle mediastinum
Phrenic Nerve (C3-C5): Accompanied by the ______ vessels (br. of internal thoracic)
pericardiacophrenic
Important landmark helping to identify Left Recurrent Laryngeal Nerve
tracheal- esophageal groove
Esophagus: Posterior to the arch of the aorta and ___
pericardium (left ventricle)
Esophagus: Passes through esophageal hiatus at
T10
Esophagus: Anterior and posterior vagal trunks form just before passing through ___
diaphragm
–Localized abnormal dilation of the aorta
–Can be thoracic or abdominal
Aneurysm of the Aorta
Causes: high blood pressure, high cholesterol, atherosclerosis, sudden traumatic injury (relating to heart)
Aneurysm of the Aorta
Surgical treatment for Aortic Aneurysm
open abdominal or open chest repair (replaced with synthetic graft), endovascular repair (using stent graft)
