Thorax 4 Flashcards by syed kamran

What divides the superior and inferior
areas of mediastinum?

Sternal angle

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What is the ascending aorta within?

Ascending within pericardial sac

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What does the aortic arch lie behind?

Arch lies behind manubrium sterni, in front of trachea

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At what level does the arch of aorta become continuous with the descending aorta?

Becomes continuous with descending aorta at level of
sternal angle.

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Where does the descending thoracic aorta begin?

Begins at about (vertebral level) T4-T5
from the arch of the aorta

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What portion of the mediastinum does the descending thoracic aorta descend in?

Descends in the posterior mediastinum

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What does the descending thoracic aorta pass through before it becomes the abdominal aorta and at what vertebrae level?

Passes through the aortic hiatus of the
diaphragm at T12

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What is median arcuate ligament syndrome?

‘MALS’ is a rare condition which involves compression on coeliac trunk

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What is impaired in MALS?

Impairs blood flow – oesophagus, stomach, liver,
spleen, and other organs.

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What are symptoms of MALS?

abdominal pain, unintentional weight loss
and abdominal bruit (abnormal sound)

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What is MALS confirmed via?

Confirmed via vascular imaging

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Where are the brachiocephalic veins found in relation to the brachiocephalic trunk?

Anterior to Brachiocephalic Trunk

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What alternative route does the azygous system provide?

The azygous system of veins provides an alternative route for venous return back
to the heart via the superior vena cava in cases where the inferior vena cava is
damaged

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What veins does the right superior intercostal vein receive from?

receives the 2nd and 3rd posterior intercostal veins

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What veins does the the azygous vein receive from?

receives lower 8 right posterior intercostal
veins, right superior intercostal vein and
hemiazygous veins

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What does the left superior intercostal vein drains?

drains 2-3rd left posterior intercostal veins

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What veins does the superior (Accessory) hemiazygos vein receive?

receives 4-8th left posterior intercostal veins

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What veins does the inferior hemiazygos veins receive from?

Receives lowest 4-5 left posterior intercostal
veins

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What is the thymus involved in?

Involved in the early development of the immune
system and is largest, relative to body size, in
children

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What portion is the thymus located in?

Located in anterior portion of the superior
mediastinum lying immediately posterior to the
manubrium of the sternum

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What does the lymphatic system consist of?

Consists of lymphatic tissues and lymphatic vessels.

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What do lymphatic tissue contain?

Lymphatic tissues contain large numbers of
lymphocytes e.g. the thymus, the spleen.

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What is lymphatic tissue essential for?

Lymphatic tissue is essential for the immunological
defences.

How does the lymphatic vessels assis the cardiovascular system?

Lymphatic vessels assist the cardiovascular system
in the removal of tissue fluid from the tissue
spaces of the body  the vessels then return the
fluid to the blood.

What are the functions of the lymphatic system?

 Maintains blood volume homeostasis.  Immune response.  Filters dietary fats.

What is the appearance of lymph like?

Lymph is colourless and clear.

How does lymph move?

Lymph moves through lymphatic vessels.

What lymphatic nodes does the anterior thoracic wall drain into?

Anterior thoracic wall drain into parasternal nodes and the diaphragmatic nodes

What lymphatic nodes does the posterior thoracic wall drain into?

Posterior thoracic wall drain to intercostal nodes around the head and necks of the ribs

What nodes does the lungs drain into?

Lungs drain into tracheobronchial nodes

What do the tracheobronchial nodes drain into?

drain into the bronchomediastinal lymph trunks

What is the course of the thoracic duct?

 Starts at cisterna chyli  Ascends through thorax  Passes behind the arch of the aorta to enter the left brachiocephalic vein

What does the bronchomediastinal lymph trunk drain into?

The bronchomediastinal lymph trunks drain into the thoracic duct and its counterpart on the right

Where do preganglionic sympathetic outflow from?

Preganglionic sympathetic outflow from spinal cord segments T1-L2 -Thoracolumbar outflow

Where do some of the preganglionic sympathetic outflow neurons from the spinal cord synapse and where are they located?

Some of these neurons synapse in paravertebral ganglia located on each side of the vertebral column, which are connected

What is the size of of preganglionic fibres in the sympathetic chain and how many postganglionic neurons do they roughly synapse with? What does this facilitate?

Preganglionic fibres are short and synapse with roughly 30 postganglionic neurons  Facilitates divergence and more widespread response

How are thoracic splanchnic nerves formed and what do they supply?

The lower 8 thoracic sympathetic ganglia mainly give pre-ganglionic fibres, which are grouped together to form thoracic splanchnic nerves and supply abdominal viscera

What is the course of thoracic splanchnic nerves, where they synapse and where they innervate?

 Preganglionic fibres pass through the sympathetic chain without synapsing  Synapse in separate prevertebral ganglia (located around the blood vessels of the aorta)  Postganglionic fibres leave ganglia to innervate visceral tissues and organs within abdominopelvic cavity

What vertebrae level is the greater splanchnic nerve?

T5-T9

Where does the greater splanchnic nerve syanpse?

Synapse in coeliac ganglion - foregut

What vertebrae level is the lesser splanchnic nerve?

T9/10 or T10/11

Where does the lesser splanchnic nerve synapse?

Synapse in superior mesenteric ganglion - midgut

What vertebrae level is the least splanchnic nerve?

T12

Where does the least splanchnic nerve synapse?

Synapses in aorticorenal ganglion - kidneys

What vertebrae level is the lumbar splanchnic nerve?

L1-L2

Where does the lumbar splanchnic nerve synapse?

Synapse in the inferior mesenteric ganglion - hindgut

Where does the phrenic nerve originate from?

Originates from the cervical plexus

What does the phrenic nerve contain?

Contains motor, sensory, and sympathetic nerve fibers

What motor supply does the phrenic nerve provide?

Motor supply to the diaphragm (C3, 4, 5 keeps the diaphragm alive)

What does the phrenic nerve provide sensation to?

Sensation to the central tendon

What does each phrenic nerve provide sensation to in the thorax?

In the thorax, each phrenic nerve supplies sensation to the mediastinal parietal pleura and pericardium.

What is the course of the phrenic nerve?

 Enters the superior mediastinum lateral to vagus nerve and posterior to the brachiocephalic veins  Passes anteriorly to the hilum of the lung and over the pericardium of the heart sending small pericardial branches to it

What does the vagus nerve supply between the neck down to the second segment of the transverse colon?

Supplies motor parasympathetic fibers to all the organs except the suprarenal (adrenal) glands, from the neck down to the second segment of the transverse colon

What skeletal muscles does the vagus nerve control?

Controls a few skeletal muscles  Superior, middle and inferior pharyngeal constrictors  Muscles of the larynx

What is the course of the vagus nerve?

Descends through the neck in the carotid sheath.

What does the cardiac branch of the vagus nerve innervate?

parasympathetic innervation to the sino-atrial and atrio-ventricular nodes of the heart

What is a plexus?

a network of nerves or vessels in the body. (not from one system)