Upgrade to remove ads
2nd year anatomy
Terms in this set (59)
Define the mediastinum?
it is in the centre of the thorax between the pleural cavities, the mediastinum contains the heart, great vessels, trachea, oesophagus
What does the mediastinum extend from vertically?
extends from the thoracic outlet to the diaphragm
What is the superior thoracic aperture bound by?
posteriorly by the first thoracic vertebrae, laterally by the first pair of ribs, anteriorly by the costal cartilage of the first rib and the posterior border of the manubrium
What is the mediastinum arbitarily divided into?
Superior and inferior portions
What is the inferior mediastinum divided into?
anterior, middle, posterior
What the borders of the superior mediastinum?
superiorly: superior thoracic aperture, inferiorly extends from the sternal angle to T4-T5
What are the borders of the anterior portion of the inferior mediastinum?
laterally pleurae, posteriorly pericardium, anteriorly sternum, left transversus thoracis (muscle), 5th, 6th, 7th costal cartilages
What are the contents of the anterior portion of the inferior mediastinum?
loose areolar tissue, some lymphatic vessels, anterior mediastinal lymph glands, small mediastinal branches of the internal mammary artery
What are the contents of the middle inferior mediastinum?
heart enclosed within the pericardium, the ascending aorta, lower half of the superior vena cava with the azygos vein opening into it, the bifurcation of the trachea and the two bronchi, the pulmonary artery dividing into its two branches, the right and left pulmonary veins, phrenic nerves, some bronchial lymphatic glands, pericardiocophrenic vessels
What are the boundaries of the posterior part of the inferior mediastinum?
anteriorly: pericardium, inferiorly: the thoracic surface of the diaphragm, superiorly: the transverse thoracic plane (sternal angle and T4/T5), posteriorly: T5-T12, laterally: by the mediastinal pleura
What is the transverse thoracic plane?
An imaginary line going through the sternal angle and a line between the fourth and fifth thoracic vertebrae
What are the contents of the posterior portion of the middle mediastinum?
thoracic part of the descending aorta, azygos vein, the hemiazygos vein and the accessory hemiazygos vein, vagus nerve, splanchnic nerves (but NOT the sympathetic chain), esophagus, thoracic duct, some lymph glands
What are the contents of the superior mediastinum?
internal jugular vein, subclavian vein, arch of aorta, common carotid arteries, subclavian arteries, trachea and oesophagus
Where does the trachea bifurcate?
it bifurcates at the border of the superior and inferior mediastinum (T4/T5levels)
What are the anterior relations of the esophagus?
Trachea, T4/T5, recurrent laryngeal nerves, left bronchus, right atrium, diaphragm
At what level does the oesophagus begin?
inferior border of the circoid cartilage opposite vertebrae CVI
At what level does the oesophagus pass through the diaphragm?
at vertebral level TX
What lymphatic vessels are located in the superior mediastinum?
the thoracic duct
What important neural structures are found within the superior mediastinum?
vagus nerves, phrenic nerves, sympathetic chains
Where does the vagus nerve arise?
the anterior surface of the medulla oblongata
Through which foramen does the vagus nerve leave the skull?
through the jugular foramen
Where do the right and left recurrent laryngeal nerves arise?
from the vagus nerves within the thorax
What is the course of the right recurrent laryngeal nerve?
It hooks around the first part of the subclavian artery, ascends in the groove between the trachea and the oesophagus
What is the course of the left recurrent laryngeal nerve?
it hooks around the arch of the aorta, ascends into the neck between the trachea and the oesophagus
What is the relation of the phrenic nerves to the vagus nerves?
the phrenic nerves lie anterior to the vagus nerves within the mediastinum
What are the sympathetic trunks?
two ganglionated nerve trunks that extend the whole length of the vertebral column
How many sympathetic chain ganglia are located within the thorax?
11 or 12
At which levels of the grey matter of the spinal cord are the lateral horns located?
What is located in the lateral horns of the spinal grey matter?
cell bodies of the sympathetic connector neurones, myelinated axons of these cells leave the spinal cord in the anterior nerve roots and then pass via the white rami communicantes to the paravertebral ganglia/ sympathetic trunk
What are the 3 possible pathways that a preganglionic sympathetic fibers can take once they are in a paravertebral ganglion?
terminate within the ganglion they have entered, travel up in the sympathetic trunk to the ganglia within the cervical region, preganglionic fibers may pass through the ganglia on the thoracic part of the sympathetic trunk without synapsing and form the 3 splanchnic nerves
What is the thymus gland?
flattenned, bilobed structure lying between the sternum and the pericardium in the anterior mediastinum, it is the site of development of T-lymphocytes
What are splanchnic nerves?
They contribute to the sympathetic innervation of the viscera
What are the 3 splanchnic nerves?
greater splanchnic (T5-T9), lesser splanchnic (T9-T10), least splanchnic (T12)
where does the greater splanchnic nerve end?
in the celiac ganglion
where does the lesser splanchnic nerve end?
Where does the least splanchnic nerve end?
in the renal plexus
At what level does the inferior vena cava pierce the diaphragm?
At what level does the thoracic aorta begin and end?
lower edge of vertebra T4 and ends at the lower edge of vertebra T12
Which branches arise from the aorta within the thorax?
pericardial, bronchial, oesophageal, mediastinal, posterior intercostal, superior phrenic and subcostal arteries
At what vertebral level does the aorta pass through the diaphragm to enter the abdomen?
Which vessels contribute to the azygos system?
azygos vein on the right and the hemiazygos and the accessory hemiazygos on the left
which structures are drained by the azygos system of veins?
body wall and moves it to empty into the superior vena cava
What is the origin of the azygos vein?
it is variable but is usually formed by the union of the right ascending lumbar vein, right subcostal vein
What does the azygos vein drain into?
posterior surface of the superior vena cava
Where does the phrenic nerve pass? Through which mediastinum?
through the middle mediastinum anterior to the roots of the lung
What lymph glands does the middle mediastinum contain?
bronchial lymph glands
Where are the bronchial lymph nodes found?
in the angles between the lower part of the trachea and bronchi and in the angle between the two bronchi, they drain into the right and left bronchomediastinal trunks
At what level does the oesophagus pierce the diaphragm?
In which part of the mediastinum is the thoracic aorta located?
the posterior mediastinum
At what level does the thoracic aorta begin?
continuation of the arch of the aorta on the left side of the lower border of the body of T4
At what level does the thoracic aorta pass through the diaphragm?
As what does the thoracic duct start?
as a dilated sac the cisterna chyli (this drains abdominal viscera, walls, pelvis, perineum and lower limbs)
What is the thoracic duct?
principal channel through which lymph from most of the body is returned to the venous system
At what level does the thoracic duct start (at what level is the cisterna chyli)?
L2 to the root of the neck
On which side of the body does the thoracic duct pass through the thorax?
on the right inferiorly but crosses to the left superiorly
Which nerve is the oesophageal nerve plexus derived from?
the right and left vagus nerves divide into several branches that form the oesophageal plexus
What are the lymph nodes anterior to the aorta?
pre-aortic lymph nodes
What are the lymph nodes lateral to the aorta?
what are the lymph nodes lateral to the oesophagus?
para-oesophageal lymph nodes
This set is often in folders with...
Anatomy of the lungs and the respiratory tract
Muscles of the chest wall
You might also like...
Mediastinum, ANS packet
Thorax & Abdomen practice
Other sets by this creator
Claiming for MyDentist
Evidence based medicine & critical appraisal
Incidences that you need to know for exams
Reza's Fixed Pros Symposium
Other Quizlet sets
Anatomy III - Anterior and Middle Mediastinum
midterm 2 part 3: thorax mediastinum