Term
Trachea
location?
function:
composed of:
confused with:
branches?
vessels/innervated by
embryology |
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Definition
Trachea
location? found in superior mediastinum, directly deep to the arch of aorta. you will probably have cut the primary bronchi so look for an-upside down V shape - those will be the primary bronchi. immediately above them is the trachea.
function: part of the conducting portion of the bracheoalveloar system. tube that connects the pharynx or larynx to the lungs, allowing the passage of air
composed of: hyaline cartilage and smooth musculature
confused with: larynx, pharynx, primary bronchi
branches? at the level of the sternal angle (intervertebral disc between T4 and T5) the trachea bifurcates into the right and left principal bronchi, which will enter their respective lungs through the "root"
vessels/innervated by - The trachea is supplied with blood by the inferior thyroid arteries. The veins end in the thyroid venous plexus. The nerves are derived from the vagus*** and the recurrent nerves***, and from the sympathetic***
embryology: As the laryngotracheal bud grows, it differentiates into the future larynx. The proximal end of the bud maintains a slit-like opening into the pharynx called the glottis. The middle portion of the bud will become the trachea. The distal end divides (bifurcates) into two lung buds that grow into the right and left bronchi and the lungs. |
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Term
Carina
location
function:
composed of:
problems: |
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Definition
Carina
location? found at the bifurcation of the trachea, runs anteroposteriorly separating the right and left primary bronchi.
function: divides the right and left primary bronchi
composed of: cartilaginous ridge
problems: Widening and distortion of the carina is a serious sign because it usually indicates carcinoma of the lymph nodes around the region where the trachea divides.
Also, because the right principal bronchi is more vertical than the left, this is usually where foreign objects tend to end up. |
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Term
Right Principal Bronchus
location:
function:
composed of: (not necessary)
confused with:
nearby vessels:
problems: |
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Definition
Right Principal Bronchus
location: hilum of root of lung
this is the result of the bifurcation of the trachea. the bifurcation occurs at the sternal angle which is at the 2nd rib, intervertebral space between T4-T5.
function: part of the conducting portion of the bronchoalveolar system. allows for passage of air
composed of: a wall of 3 layers: fibrous tissue, cartilage, smooth muscle, ciliac mucosa membrane
confused with: left principal bronchi, trachea
Right principal bronchus is wider, and shorter and is more vertical than the left.
remember when looking at a body in the anatomical position, the right principal bronchus is on YOUR left and the person's right.
nearby vessels: right pulmonary artery, right superior and inferior pulmonary veins.
remember that the arteries generally follow the path of the bronchi whereas the veins do not.
problems: because the right principal bronchi is wider and more vertical than the left, this is usually where foreign objects tend to end up. |
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Term
Left Principal Bronchus
location:
function:
composed of: (not necessary)
confused with:
nearby vessels:
problems? |
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Definition
Left Principal Bronchus
location: hilum of root of lung. passes below arch of the aorta and in front of descending aorta as well as esophagus
this is the result of the bifurcation of the trachea. the bifurcation occurs at the sternal angle which is at the 2nd rib, intervertebral space between T4-T5.
function: part of the conducting portion of the bronchoalveolar system. allows for passage of air
composed of: a wall of 3 layers: fibrous tissue, cartilage, smooth muscle, ciliac mucosa membrane
confused with: right principal bronchi, trachea
Right principal bronchus is wider, and shorter and is more vertical than the left.
Left principal bronchus is long and narrow.
remember when looking at a body in the anatomical position, the left principal bronchus is on YOUR right and the person's left.
nearby vessels: left pulmonary artery, left superior and inferior pulmonary veins.
remember that the arteries generally follow the path of the bronchi whereas the veins do not.
problems: the left principal bronchi is less likely to be the location where foreign objects get stuck because the right principal bronchi is wider and more vertical than the left |
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Term
Esophagus
location?
function:
composed of:
confused with:
branches/continues into
vessels/innervated by
problems? * |
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Definition
Esophagus
location? found in the posterior mediastinum, directly above the descending thoracic aorta and behind arch of aorta
function: The portion of the digestive canal between the pharynx and stomach. It functions to transport food from the throat to the stomach and to keep the contents of the stomach in the stomach.
composed of: coated with mucus and surrounded by muscles, and pushes food to the stomach by sequential waves of contraction.
confused with: descending aorta, trachea, thoracic duct
-always remember that the esophagus is directly deep to the arch of the aorta and as it courses posteriorly, superficial to the descending aorta
branches/continues into: connects pharynx (pharyngoesophageal constriction) and stomach (diaphragmatic constriction)
vessels/innervated by: After supplying the heart and lungs, the right and left vagus nerves follow a medial course on the anterior and posterior surfaces of the esophagus, forming the esophageal plexus. The preganglionic parasympathetic fibers synapse in microscopic ganglia located between the two layers of the smooth muscle of the esophagus, which they supply. En route to the esophageal hiatus of the diaphragm, the vagal fibers are joined by postganglionic sympathetic fibers. Once in the abdomen the left and right vagus nerves are known as the anterior and posterior gastric nerves, respectively.
problems: If you are examining a patient who has swallowed a caustic substance or who you suspect may have carcinoma of the esophagus, the three sites that should be evaluated first are the areas where this organ is constricted. The first is at its origin from the laryngopharynx (pharyngoesophageal constriction), the second is where both the trachea and arch of the aorta lie directly anterior to it (aortobronchial constriction), and the third is where it passes through the diaphragm en route to the cardiac portion of the stomach (diaphragmatic constriction). |
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Term
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Definition
How to find it on the cadaver:
Follow either the right or left vagus nerve. As you come down, you should see the recurrent laryngeal nerve. Continue down and you should see it branch off and join the cardiac plexus. As you continue further down, you will see a meshwork of nerves, this is the esophageal plexus.
After supplying the heart and lungs, the right and left vagus nerves follow a medial course on the anterior and posterior surfaces of the esophagus, forming the esophageal plexus.
1) preganglionic parasympathetic fibers synapse in microscopic ganglia located between the two layers of the smooth muscle of the esophagus, which they supply.
2) En route to the esophageal hiatus of the diaphragm, the vagal fibers are joined by postganglionic sympathetic fibers. Once in the abdomen the left and right vagus nerves are known as the anterior and posterior gastric nerves, respectively. |
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Term
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Definition
originates at the union of the ascending lumbar and subcostal veins (these are below the diaphragm)
the azygos vein ascends anteriorly to the vertebral bodies to the level of T4 and will arch over the root of the right lung and terminate in Superior Vena Cava.
Receives venous return from the posterior intercostal veins, hemiazygos and accessory hemiazygos vein, as well as the right Superior intercostal vein.
The azygos system communicates with both the external and internal vertebral venous plexi (because of the posterior intercostal veins). This can be bad because these connections are of potential clinical importance in the spread of infection or metastases.
The Inferior Vena Cava also has connections to azygos venous system via the ascending lumbar veins. --> This provides for collateral circulatory routing in case of an obstruction in the IVC. |
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Term
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Definition
How to find on cadaver:
the azygos vein will be seen on the right side of the posterior mediastinum coursing anteriorly until vertebral level T4 where it will arch over the root of right lung and terminate in the Superior Vena Cava. This is called the arch of the azygos vein.
the arch can be displaced laterally, thereby creating a pleural septum separating an azygos lobe from the upper lobe of the right lung. |
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Term
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Definition
It will be found on the left side of the vertebral column in the posterior mediastinum.
The hemiazygos vein originates from the ascending lumbar and subcostal veins.
It courses superiorly and drains the lower four posterior intercostal veins and ends at Vertebral Level T9.
The hemiazygos may or may not be continuous superiorly with the accessory hemiazygos vein. |
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Term
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Definition
a vein on the left side of the vertebral column in the posterior mediastinum that generally drains the fifth through eighth intercostal spaces on the left side of the body.
Ends at vertebral level T8. |
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Term
| Right Superior Intercostal Vein |
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Definition
Found on the right (obviously) side of the posterior mediastinum.
The right superior intercostal vein drains the 2nd, 3rd, and 4th posterior intercostal veins on the right side of the body. It flows into the azygos vein.
Mentioned in notes as follows:
The azygos vein receives return from right superior intercostal vein, posterior intercostal veins, hemiazygos and accessory hemiazygos veins. |
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Term
| Posterior Intercostal Veins |
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Definition
these veins drain the intercostal spaces posteriorly. they can be found running with the "VAN" (Vein Artery Nerve, in that order going from superior to inferior) right on the underside of the rib.
There are eleven posterior intercostal veins on each side.
Mentioned in notes as:
The azygos vein receives venous return from the posterior intercostal veins, the hemiazygos and accessory hemiazygos veins and the right superior intercostal vein.
Via its tributaries from the posterior intercostal veins, the azygos venous system communicates with both the external and internal vertebral venous plexus. These connections are of potential clinical importance in the spread of infection or metastases. |
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Term
| Descending Thoracic Aorta |
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Definition
Found in the posterior mediastinum.
Begins at lower border of T4 vertebra and is continuous with arch of aorta.
Ends in front of vertebral level T12 (also known as the aortic hiatus and becomes abdominal aorta.
The esophagus, with its accompanying plexus of nerves, lies on the right side of the aorta above; but at the lower part of the thorax it is placed in front of the aorta, and, close to the diaphragm, is situated on its left side.
Branches of thoracic aorta:
Visceral:
1) Bronchial arteries,
2) Mediastinal arteries,
3) esophageal arteries,
4) Pericardial arteries
Parietal:
5) Superior phrenic artery
6) Subcostal arteries
7) Posterior intercostal arteries |
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Term
| Posterior Intercostal Arteries |
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Definition
The posterior intercostal arteries are branches of the descending thoracic aorta.
They supply the intercostal muscles, the muscles of the back, pleurae, ribs and skin.
They have numerous (radicular) branches to the thoracic spinal cord as well.
These posterior intercostal arteries anastamose with the anterior and posterior spinal arteries, which supply the cervical spinal cord.
Should it be necessary, the anterior and posterior intercostal arteries can form functional anastomotic connections. |
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Term
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Definition
The thoracic duct is the largest lymph vessel in the body.
Starts @ cisterna chyli (a dilated sac in the abdomen)
The intestinal lumbar trunks empty into the thoracic duct.
It passes through the aortic hiatus of the diaphragm, continues to the posterior mediastinum and receives lymph from the intercostal trunks and vessels.
It drains the bronchomediostinal, jugular, and subclavian trunks and empties into the venous system at the junction of the left subclavian and jugular vein.
When the thoracic duct is blocked or damaged a large amount of lymph can quickly accumulate in the pleural cavity
**Can be found on the right side of the vertebral body in the posterior mediastinum. |
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Term
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Definition
The sympathetic chain can be seen in the the posterior mediastinum of the cadaver running just lateral to the vertebral bodies
It goes from the base of the skull to the coccyx.
The sympathetic chain allows nerve fibers to travel to spinal nerves that are superior and inferior to the one in which they originated
The cell bodies of preganglionic sympathetic neurons can be found in intermediolateral cell column of the gray matter from T1-L2.
These axons will exit via the white matter of the spinal cord via the ventral root and continue on to a "white ramus communicans." The white ramus communicans allows these preganglionic sympathetic neurons to enter the sympathetic chain and
a) travel up or down the sympathetic chain to their desired location
b) come together and form either the throacic or lumbar splanchnic nerves (from T5-T9)
OR
c) synapse with a postganglionic sympathetic neuron and join a "gray ramus communicans."
If the postganglionic sympathetic neuron chooses to join the gray ramus communicans, it has the choice to join either the ventral or dorsal rami of the spinal nerve. --> These will act on smooth muscles of blood vessels, hair shafts and hair glands.
Embryology: A population of neural crest cells migrates ventrally forming a series of paired clusters located lateral to the developing paired sinal nerves which will become the interconnected ganglia of the paravertebral sympathetic chain. |
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Term
| Sympathetic Chain Ganglia |
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Definition
The sympathetic chain ganglia can be seen in the the posterior mediastinum of the cadaver running just lateral to the vertebral bodies
The sympathetic chain ganglia house the cell bodies of the postganglionic sympathetic neurons and this is the site for the synapse with the preganglionic sympathetic neurons.
The cell bodies of preganglionic sympathetic neurons can be found in intermediolateral cell column of the gray matter from T1-L2, but the sympathetic chain ganglia can be found running from the upper neck down to the coccyx.
These axons will exit via the white matter of the spinal cord via the ventral root and continue on to a "white ramus communicans." The white ramus communicans allows these preganglionic sympathetic neurons to enter the sympathetic chain and
a) travel up or down the sympathetic chain to their desired location
b) come together and form either the throacic or lumbar splanchnic nerves (from T5-T9)
OR
c) synapse with a postganglionic sympathetic neuron and join a "gray ramus communicans."
If the postganglionic sympathetic neuron chooses to join the gray ramus communicans, it has the choice to join either the ventral or dorsal rami of the spinal nerve. --> These will act on smooth muscles of blood vessels, hair shafts and hair glands.
Embryology: A population of neural crest cells migrates ventrally forming a series of paired clusters located lateral to the developing paired sinal nerves which will become the interconnected ganglia of the paravertebral sympathetic chain.
Abnormalities:
Clusters of neural crest cells that fail to migrate to their appropriate positions often persist in the paravertebral area where they form catecholamine-producing tumors.
--> Pheochromocytoma is a tumor that is localized in the adrenal gland. Individuals with this type of tumor have sustained or transient episodes of high blood pressure accompanied by severe headaches, palpitations, and nervousness. |
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Term
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Definition
The rami communicans can be seen in the the posterior mediastinum of the cadaver just lateral to the vertebral bodies. We do not need to differentiate between white and gray rami communicans, if tagged.
The white rami communicans are found from spinal level T1-L2, whereas gray rami communicans can be found throughout the extent of the sympathetic chain.
White rami communicans contain: preganglionic sympathetic neurons that are entering the sympathetic chain and the centrally directed processes of the visceral afferent "pain" neurons (these visceral afferent neurons follow the sympathetic chain)
Gray rami communicans contain postganglionic sympathetic neurons that are exiting the sympathetic chain and are going to the ventral or dorsal rami.
The cell bodies of preganglionic sympathetic neurons can be found in intermediolateral cell column of the gray matter from T1-L2.
These axons will exit via the white matter of the spinal cord via the ventral root and continue on to a "white ramus communicans." The white ramus communicans allows these preganglionic sympathetic neurons to enter the sympathetic chain and
a) travel up or down the sympathetic chain to their desired location
b) come together and form either the throacic or lumbar splanchnic nerves (from T5-T9)
OR
c) synapse with a postganglionic sympathetic neuron and join a "gray ramus communicans."
If the postganglionic sympathetic neuron chooses to join the gray ramus communicans, it has the choice to join either the ventral or dorsal rami of the spinal nerve. --> These will act on smooth muscles of blood vessels, hair shafts and hair glands. |
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Term
| Greater Splanchnic Nerves |
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Definition
these are preganglionic sympathetic neurons that do not synapse in the sympathetic chain.
cell bodies are found in in the intermediolateral cell column of the gray matter from T5-T9
The preganglionic sympathetic neurons will pass through the diaphragm and synapse in the celiac ganglia.
The postganglionic sympathetic neurons are distributed with the celiac branches to the upper GI tract.
Afferent (pain) fibers follow the greater splanchnic nerves and their cell bodies are located in the dorsal root ganglion in vertebral level T5-T9. |
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