kumc 11 medias tin um student

8/2/2019 Kumc 11 Medias Tin Um Student

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THORACIC CAVITYTHORACIC CAVITY

MEDIASTINUMMEDIASTINUM


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MediastinumMediastinum

Mediastinum = space between lungs.Mediastinum = space between lungs.

Superior mediastinum:Superior mediastinum:

Separated from inferior by horizontal planeSeparated from inferior by horizontal planebetween sternal angle and IV disc T4-T5.between sternal angle and IV disc T4-T5.

Fig. 1.34, p 135.Fig. 1.34, p 135.


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MediastinumMediastinum

Inferior:Inferior:

Anterior:Anterior:

Middle:Middle:

Posterior:Posterior:


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Superior MediastinumSuperior Mediastinum

Retrosternal:Retrosternal:

Great vessels and branches.Great vessels and branches.

Thymus.Thymus.

Prevertebral:Prevertebral:TracheaTrachea

EsophagusEsophagus

Thoracic ductThoracic ductSympathetic trunksSympathetic trunks

Vagus nervesVagus nerves


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Inferior MediastinumInferior Mediastinum

Anterior:Anterior:

Thymus, fat, lymph nodesThymus, fat, lymph nodes

Middle:Middle:PericardiumPericardium

Phrenic nervesPhrenic nerves

Pericardiacophrenic arteryPericardiacophrenic artery

Heart and great vesselsHeart and great vessels


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Inferior MediastinumInferior Mediastinum

Posterior:Posterior:

EsophagusEsophagus

Thoracic ductThoracic duct

Aorta and branchesAorta and branches

Vagus nervesVagus nerves

Sympathetic trunksSympathetic trunks

Azygos system of veinsAzygos system of veins


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SUPERIOR MEDIASTINUMSUPERIOR MEDIASTINUM


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ThymusThymus

Occupies superior mediastinum on eitherOccupies superior mediastinum on either

side of the midline.side of the midline.

Behind manubrium.Behind manubrium.

Covered by converging pleura of theCovered by converging pleura of the

lungs.lungs.

Involutes with fat after puberty.Involutes with fat after puberty.


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ThymusThymus

Blood supply:Blood supply:

Anterior mediastinal arteries from internalAnterior mediastinal arteries from internal

thoracic artery.thoracic artery.

Inferior thyroid arteries from subclavianInferior thyroid arteries from subclavian

artery.artery.

Venous drainage:Venous drainage:

Into left brachiocephalic vein.Into left brachiocephalic vein.


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ThymusThymus

Innervation:Innervation:

Vagus nerve.Vagus nerve.

Cardiac sympathetic plexus.Cardiac sympathetic plexus.


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Middle Mediastinum (inferior)Middle Mediastinum (inferior)

Pericardium:Pericardium:

Encloses heart.Encloses heart.

(Fig. 1.35, p 137).(Fig. 1.35, p 137).


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Visceral (serous) (Fig 1.37, p 139):Visceral (serous) (Fig 1.37, p 139):

= epicardium.= epicardium.

Arterial mesocardium.Arterial mesocardium.

Venous mesocardium.Venous mesocardium.

Transverse sinus:Transverse sinus:

Space between arterial and venousSpace between arterial and venous

mesocardium.mesocardium.

Oblique sinus:Oblique sinus:

Space between right and left pulmonary veins.Space between right and left pulmonary veins.


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Pericardial cavity.Pericardial cavity.

Parietal (serous):Parietal (serous):

Fused to fibrous pericardium.Fused to fibrous pericardium.

Fibrous:Fibrous:

Fused with central tendon of diaphragm:Fused with central tendon of diaphragm:

Pericardiacophrenic ligament.Pericardiacophrenic ligament.

Fused with sternum:Fused with sternum:

Superior and inferior sternopericardialSuperior and inferior sternopericardial

ligaments.ligaments.


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POSTERIORPOSTERIOR

MEDIASTINUMMEDIASTINUM


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EsophagusEsophagus

From base of neck to:From base of neck to:

Left of midline to:Left of midline to:

Midline to:Midline to:

Left of midline.Left of midline.

Passes through diaphragm at level of T10.Passes through diaphragm at level of T10.

Lies:Lies:Behind trachea.Behind trachea.

In front of vertebral column.In front of vertebral column.


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Esophagus Blood SupplyEsophagus Blood Supply

Bronchial artery.Bronchial artery.

Thoracic aorta.Thoracic aorta.

Left gastric artery.Left gastric artery.Left inferior phrenic artery.Left inferior phrenic artery.


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Esophagus InnervationEsophagus Innervation

Esophageal plexus:Esophageal plexus:

Continuation of posterior pulmonary plexus.Continuation of posterior pulmonary plexus.

Formed by right and left vagus nerves:Formed by right and left vagus nerves:

Right vagus nerveRight vagus nerve posterior vagus nerve.posterior vagus nerve.

Left vagus nerveLeft vagus nerve anterior vagus nerve.anterior vagus nerve.


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Esophagus InnervationEsophagus Innervation

Upper third:Upper third:

Voluntary muscle.Voluntary muscle.

Innervated by recurrent laryngeal nerve.Innervated by recurrent laryngeal nerve.

Lower two-thirds:Lower two-thirds:

Involuntary muscle.Involuntary muscle.

Innervated by vagus and sympathetic chain.Innervated by vagus and sympathetic chain.


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Left Thoracic ductLeft Thoracic duct

Arises from cisterna chyli:Arises from cisterna chyli:

At union of right and left lumbar trunks.At union of right and left lumbar trunks.

Begins on the front of vertebral body T-12Begins on the front of vertebral body T-12

or L-1.or L-1.

Runs up through the thorax along the frontRuns up through the thorax along the front

of the vertebral column.of the vertebral column.

At first it lies to the right of midline.At first it lies to the right of midline.


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It moves over to the left side when itIt moves over to the left side when it

reaches level T-5.reaches level T-5.

Receives most of lymph from body belowReceives most of lymph from body below

diaphragm.diaphragm.

Drains left side of thoracic cavity and partDrains left side of thoracic cavity and part

of right.of right.


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Receives lymph from left internal jugularReceives lymph from left internal jugular

lymph trunk.lymph trunk.

Receives lymph from left subclavian lymphReceives lymph from left subclavian lymph

trunk.trunk.

Empties into venous system at junction of:Empties into venous system at junction of:

Left internal jugular vein.Left internal jugular vein.

Left subclavian vein.Left subclavian vein.


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Right Thoracic ductRight Thoracic duct

Drains upper right thoracic cavity, rightDrains upper right thoracic cavity, right

upper extremity, and right side of headupper extremity, and right side of head

and neck.and neck.


Right internal jugular vein.Right internal jugular vein.

Right subclavian vein.Right subclavian vein.


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Thoracic Sympathetic ChainThoracic Sympathetic Chain

Lies against neck of ribs andLies against neck of ribs and

costovertebral junctions.costovertebral junctions.

12 thoracic ganglia pairs:12 thoracic ganglia pairs:

First one often fused with inferior cervicalFirst one often fused with inferior cervical

ganglion:ganglion:

Referred to as stellate ganglion collectively.Referred to as stellate ganglion collectively.


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Cervical ganglia:Cervical ganglia:

Superior.Superior.

Middle.Middle.

Inferior.Inferior.


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The preganglionic sympathetic supply toThe preganglionic sympathetic supply tothe thoracic viscera are from T15.the thoracic viscera are from T15.

The postganglionics are from:The postganglionics are from:

Superior, middle, and inferior cervicalSuperior, middle, and inferior cervicalganglia.ganglia.

T1-T5 paravertebral ganglia.T1-T5 paravertebral ganglia.

They exit the chain as direct fibers andThey exit the chain as direct fibers andtravel downwards to enter the thorax:travel downwards to enter the thorax:

As cardiopulmonary splanchnic nerves.As cardiopulmonary splanchnic nerves.


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The cardiopulmonary splanchnic nervesThe cardiopulmonary splanchnic nerves

travel on their own and do not accompanytravel on their own and do not accompany

other nerves or vessels.other nerves or vessels.

Function:Function:

Coronary artery dilation.Coronary artery dilation.

Increase heart rate.Increase heart rate.

Bronchodilation.Bronchodilation.


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Splanchnic NervesSplanchnic Nerves

Composed of preganglionic fibers andComposed of preganglionic fibers and

visceral sensory fibers.visceral sensory fibers.

Supply abdominal viscera.Supply abdominal viscera.

Synapse in prevertebral ganglia.Synapse in prevertebral ganglia.

Refer in text to Figure 1.41, page 63.Refer in text to Figure 1.41, page 63.


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Greater:Greater:

T5-T9.T5-T9.

Synapses in celiac ganglion.Synapses in celiac ganglion.

Lesser:Lesser:

T10-T11.T10-T11.

Synapses in the superior mesentericSynapses in the superior mesenteric

ganglion.ganglion.


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Least:Least:

T12.T12.

Synapses in the aorticorenal ganglion.Synapses in the aorticorenal ganglion.


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Vagus NerveVagus Nerve

Cranial nerve XCranial nerve X

Major parasympathetic supply to thoracicMajor parasympathetic supply to thoracic

and abdominal viscera.and abdominal viscera.


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Course of Vagus NerveCourse of Vagus Nerve

Parallel to esophagus:Parallel to esophagus:

Innervates esophagusInnervates esophagus

Passes posterior to root of lung on eachPasses posterior to root of lung on each

side.side.

Pierces diaphragm with esophagus.Pierces diaphragm with esophagus.

Becomes gastric nerve.Becomes gastric nerve.Supplies viscera in thoracic cavity.Supplies viscera in thoracic cavity.


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Vagus Nerve BranchesVagus Nerve Branches

Cardiac branches to cardiac plexus.Cardiac branches to cardiac plexus.

Pulmonary branches to pulmonary plexus.Pulmonary branches to pulmonary plexus.

Esophageal branches to esophagealEsophageal branches to esophagealplexus.plexus.


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Vagus Nerve BranchesVagus Nerve Branches

Left recurrent laryngeal nerve from leftLeft recurrent laryngeal nerve from left

vagus:vagus:

Hooks around arc of aorta to left ofHooks around arc of aorta to left of

ligamentum arteriosum.ligamentum arteriosum.

Right recurrent laryngeal nerve from rightRight recurrent laryngeal nerve from right

vagus:vagus:

Hooks around subclavian artery.Hooks around subclavian artery.

Therefore: arises in neck, not thorax.Therefore: arises in neck, not thorax.


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Phrenic NervePhrenic Nerve

Arises in neck from:Arises in neck from:

Ventral rami of C3-5 (C4 = majorVentral rami of C3-5 (C4 = majorcontribution)contribution)

Passes anterior to pulmonary root on eachPasses anterior to pulmonary root on eachside (only nerve to do so).side (only nerve to do so).

Sole motor innervation to diaphragm.Sole motor innervation to diaphragm.

Sensory fibers to pericardium, mediastinalSensory fibers to pericardium, mediastinalpleura, and pleural and peritonealpleura, and pleural and peritonealcoverings of diaphragm.coverings of diaphragm.


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Phrenic NervePhrenic Nerve

Pain via phrenic nerves usually referred toPain via phrenic nerves usually referred to

base of neck and tip of shoulder.base of neck and tip of shoulder.

Accompanied by pericardiacophrenicAccompanied by pericardiacophrenic

arteries.arteries.

Branches of internal thoracic arteriesBranches of internal thoracic arteries


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Lymphatic DrainageLymphatic Drainage

50 tracheobronchial lymph nodes :50 tracheobronchial lymph nodes :

Some of the largest lymph nodes in theSome of the largest lymph nodes in thebody.body.

Include:Include:ParatrachealParatracheal

Superior tracheobronchialSuperior tracheobronchial

Inferior tracheobroncialInferior tracheobroncial

BronchopulmonaryBronchopulmonaryPulmonaryPulmonary

Text: p 131, Fig. 1.32Text: p 131, Fig. 1.32


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Lymph Drainage of Thoracic CavityLymph Drainage of Thoracic Cavity

Parasternal nodes:Parasternal nodes:

Lie behind sternum along course of internalLie behind sternum along course of internal

thoracic artery.thoracic artery.

Receive lymph from thoracic wall, upperReceive lymph from thoracic wall, upper

anterior abdominal wall, and diaphragm.anterior abdominal wall, and diaphragm.

Also receive significant amount of lymphAlso receive significant amount of lymph

from mammary gland.from mammary gland.Dump into parasternal lymph channel.Dump into parasternal lymph channel.


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Posterior intercostal nodes:Posterior intercostal nodes:

Lie in posterior intercostal space betweenLie in posterior intercostal space between

heads of ribs.heads of ribs.

Receive lymph from thoracic wall andReceive lymph from thoracic wall and

paravertebral regions.paravertebral regions.

Drain into thoracic duct:Drain into thoracic duct:

From left and lower right.From left and lower right.Drain into right lymphatic duct:Drain into right lymphatic duct:

From upper right.From upper right.


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Diaphragmatic nodes:Diaphragmatic nodes:

Lie on upper surface of diaphragm.Lie on upper surface of diaphragm.

Receive lymph from diaphragm, pericardium,Receive lymph from diaphragm, pericardium,

upper surface of liver.upper surface of liver.

Drain to parasternal and posteriorDrain to parasternal and posterior

mediastinal nodes.mediastinal nodes.


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Posterior mediastinal nodes:Posterior mediastinal nodes:

Lie along esophagus and descendingLie along esophagus and descending

thoracic aorta.thoracic aorta.

Brachiocephalic nodes:Brachiocephalic nodes:

Lie along brachiocephalic veins.Lie along brachiocephalic veins.


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Lymphatic Drainage of ThoraxLymphatic Drainage of Thorax

Lymph TrunksLymph Trunks

Bronchiomediastinal lymph trunks receiveBronchiomediastinal lymph trunks receive

lymph from:lymph from:

Posterior mediastinal nodesPosterior mediastinal nodes

Brachiocephalic nodesBrachiocephalic nodes

Tracheobronchial nodesTracheobronchial nodes

Parasternal nodesParasternal nodes


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Thoracic DuctThoracic Duct

Begins in abdomen on right side of midline.Begins in abdomen on right side of midline.

Receives most of lymph from body belowReceives most of lymph from body below

diaphragm.diaphragm.

Drains left side of thoracic cavity and part ofDrains left side of thoracic cavity and part of

right.right.

Receives lymph from left internal jugularReceives lymph from left internal jugularlymph trunk.lymph trunk.


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Thoracic Duct (cont.):Thoracic Duct (cont.):

Receives lymph from left subclavian lymphReceives lymph from left subclavian lymph

trunk.trunk.


Left internal jugular vein.Left internal jugular vein.

Left subclavian vein.Left subclavian vein.


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Right Lymphatic Duct:Right Lymphatic Duct:

Drains upper right thoracic cavity, right upperDrains upper right thoracic cavity, right upper

extremity, and right side of head and neck.extremity, and right side of head and neck.


Right internal jugular vein.Right internal jugular vein.

Right subclavian vein.Right subclavian vein.

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