thoracic cavity mediastinum. mediastinum mediastinum = space between lungs. mediastinum = space...

THORACIC CAVITYTHORACIC CAVITY

MEDIASTINUMMEDIASTINUM

MediastinumMediastinum

Mediastinum = space between lungs.Mediastinum = space between lungs.Superior mediastinum:Superior mediastinum:

Separated from inferior by horizontal plane Separated from inferior by horizontal plane between 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.

MediastinumMediastinum

Inferior:Inferior:Anterior:Anterior:

Middle:Middle:

Posterior:Posterior:

Superior MediastinumSuperior Mediastinum

Retrosternal:Retrosternal:Great vessels and branches.Great vessels and branches.Thymus.Thymus.

Prevertebral:Prevertebral:TracheaTracheaEsophagusEsophagusThoracic ductThoracic ductSympathetic trunksSympathetic trunksVagus nervesVagus nerves

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

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

SUPERIOR SUPERIOR MEDIASTINUMMEDIASTINUM

ThymusThymus

Occupies superior mediastinum on either Occupies superior mediastinum on either side of the midline.side of the midline.

Behind manubrium.Behind manubrium.Covered by converging pleura of the Covered by converging pleura of the

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

ThymusThymus

Blood supply:Blood supply:Anterior mediastinal arteries from internal Anterior 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.

ThymusThymus

Innervation:Innervation:Vagus nerve.Vagus nerve.

Cardiac sympathetic plexus.Cardiac sympathetic plexus.

Middle Mediastinum (inferior)Middle Mediastinum (inferior)

Pericardium:Pericardium:Encloses heart.Encloses heart.

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


Pericardium:Pericardium: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 venous Space between arterial and venous mesocardium.mesocardium.

Oblique sinus:Oblique sinus:Space between right and left pulmonary Space between right and left pulmonary

veins.veins.


Pericardium:Pericardium: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 sternopericardial Superior and inferior sternopericardial ligaments.ligaments.


Pericardium:Pericardium:Blood supply (Fig. 1.38, p 139):Blood supply (Fig. 1.38, p 139):

Pericardial arteries.Pericardial arteries.

Pericardiacophrenic arteries.Pericardiacophrenic arteries.

Musculophrenic arteries.Musculophrenic arteries.

Nerve supply:Nerve supply:

CN X.CN X.

Phrenic nerve.Phrenic nerve.

Sympathetic trunk.Sympathetic trunk.

POSTERIOR POSTERIOR MEDIASTINUMMEDIASTINUM

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.

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.

Esophagus InnervationEsophagus Innervation

Esophageal plexus:Esophageal plexus:Continuation of posterior pulmonary Continuation of posterior pulmonary

plexus.plexus.

Formed by right and left vagus nerves:Formed by right and left vagus nerves:Right vagus nerve Right vagus nerve posterior vagus posterior vagus

nerve.nerve.

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

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 Innervated by vagus and sympathetic chain.chain.

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-12 Begins on the front of vertebral body T-12 or L-1.or L-1.

Runs up through the thorax along the front Runs 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.


It moves over to the left side when it It moves over to the left side when it reaches level T-5.reaches level T-5.

Receives most of lymph from body below Receives most of lymph from body below diaphragm. diaphragm.

Drains left side of thoracic cavity and part Drains left side of thoracic cavity and part of right.of right.


Receives lymph from left internal jugular Receives lymph from left internal jugular lymph trunk. lymph trunk.

Receives lymph from left subclavian lymph Receives 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.

Right Thoracic ductRight Thoracic duct

Drains upper right thoracic cavity, right Drains upper right thoracic cavity, right upper extremity, and right side of head upper extremity, and right side of head and neck.and neck.

Empties into venous system at junction of:Empties into venous system at junction of:Right internal jugular vein.Right internal jugular vein.

Right subclavian vein.Right subclavian vein.

Thoracic Sympathetic ChainThoracic Sympathetic Chain

Lies against neck of ribs and Lies against neck of ribs and costovertebral junctions.costovertebral junctions.

12 thoracic ganglia pairs:12 thoracic ganglia pairs:First one often fused with inferior cervical First one often fused with inferior cervical ganglion:ganglion:

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


Cervical ganglia:Cervical ganglia:

Superior.Superior.

Middle.Middle.

Inferior.Inferior.


The preganglionic sympathetic supply to The preganglionic sympathetic supply to the thoracic viscera are from T1–5. the thoracic viscera are from T1–5.

The postganglionics are from:The postganglionics are from:Superior, middle, and inferior cervical Superior, middle, and inferior cervical

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

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

As cardiopulmonary splanchnic nerves.As cardiopulmonary splanchnic nerves.


The cardiopulmonary splanchnic nerves The cardiopulmonary splanchnic nerves travel on their own and do not accompany travel 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.

Splanchnic NervesSplanchnic Nerves

Composed of preganglionic fibers and Composed 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.


Greater:Greater:T5-T9.T5-T9.

Synapses in celiac ganglion.Synapses in celiac ganglion.Lesser:Lesser:

T10-T11.T10-T11.

Synapses in the superior mesenteric Synapses in the superior mesenteric ganglion.ganglion.


Least:Least:T12.T12.

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

Vagus NerveVagus Nerve

Cranial nerve XCranial nerve XMajor parasympathetic supply to thoracic Major parasympathetic supply to thoracic

and abdominal viscera.and abdominal viscera.

Course of Vagus NerveCourse of Vagus Nerve

Parallel to esophagus:Parallel to esophagus:Innervates esophagusInnervates esophagus

Passes posterior to root of lung on each Passes 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.

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 esophageal Esophageal branches to esophageal

plexus.plexus.

Vagus Nerve BranchesVagus Nerve Branches

Left recurrent laryngeal nerve from left Left recurrent laryngeal nerve from left vagus:vagus:

Hooks around arc of aorta to left of Hooks around arc of aorta to left of ligamentum arteriosum.ligamentum arteriosum.

Right recurrent laryngeal nerve from right Right 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.

Phrenic NervePhrenic Nerve

Arises in neck from:Arises in neck from:Ventral rami of C3-5 (C4 = major Ventral rami of C3-5 (C4 = major

contribution)contribution)Passes anterior to pulmonary root on each Passes anterior to pulmonary root on each

side (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, mediastinal Sensory fibers to pericardium, mediastinal

pleura, and pleural and peritoneal pleura, and pleural and peritoneal coverings of diaphragm.coverings of diaphragm.

Phrenic NervePhrenic Nerve

Pain via phrenic nerves usually referred to Pain via phrenic nerves usually referred to base of neck and tip of shoulder.base of neck and tip of shoulder.

Accompanied by pericardiacophrenic Accompanied by pericardiacophrenic arteries.arteries.

Branches of internal thoracic arteriesBranches of internal thoracic arteries

Lymphatic DrainageLymphatic Drainage

50 tracheobronchial lymph nodes :50 tracheobronchial lymph nodes :Some of the largest lymph nodes in the Some of the largest lymph nodes in the

body.body.Include:Include:

ParatrachealParatrachealSuperior tracheobronchialSuperior tracheobronchialInferior tracheobroncialInferior tracheobroncialBronchopulmonaryBronchopulmonaryPulmonaryPulmonary

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

Lymph Drainage of Thoracic CavityLymph Drainage of Thoracic Cavity

Parasternal nodes:Parasternal nodes:Lie behind sternum along course of Lie behind sternum along course of

internal internal thoracic artery.thoracic artery.

Receive lymph from thoracic wall, upper Receive lymph from thoracic wall, upper anterior abdominal wall, and diaphragm.anterior abdominal wall, and diaphragm.

Also receive significant amount of lymph Also receive significant amount of lymph from mammary gland.from mammary gland.

Dump into parasternal lymph channel.Dump into parasternal lymph channel.


Posterior intercostal nodes:Posterior intercostal nodes:Lie in posterior intercostal space between Lie in posterior intercostal space between

heads of ribs.heads of ribs.

Receive lymph from thoracic wall and Receive 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.


Diaphragmatic nodes:Diaphragmatic nodes:Lie on upper surface of diaphragm.Lie on upper surface of diaphragm.

Receive lymph from diaphragm, Receive lymph from diaphragm, pericardium, pericardium, upper surface of liver.upper surface of liver.

Drain to parasternal and posterior Drain to parasternal and posterior mediastinal nodes.mediastinal nodes.


Posterior mediastinal nodes:Posterior mediastinal nodes:Lie along esophagus and descending Lie along esophagus and descending

thoracic aorta.thoracic aorta.Brachiocephalic nodes:Brachiocephalic nodes:

Lie along brachiocephalic veins.Lie along brachiocephalic veins.

Lymphatic Drainage of ThoraxLymphatic Drainage of Thorax

Lymph TrunksLymph TrunksBronchiomediastinal lymph trunks receive Bronchiomediastinal lymph trunks receive lymph from:lymph from:

Posterior mediastinal nodesPosterior mediastinal nodes

Brachiocephalic nodesBrachiocephalic nodes

Tracheobronchial nodesTracheobronchial nodes

Parasternal nodesParasternal nodes


Thoracic DuctThoracic DuctBegins in abdomen on right side of midline.Begins in abdomen on right side of midline.

Receives most of lymph from body below Receives most of lymph from body below diaphragm.diaphragm.

Drains left side of thoracic cavity and part Drains left side of thoracic cavity and part of of right.right.

Receives lymph from left internal jugular Receives lymph from left internal jugular lymph trunk.lymph trunk.


Thoracic Duct (cont.):Thoracic Duct (cont.):Receives lymph from left subclavian lymph Receives 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.


Right Lymphatic Duct:Right Lymphatic Duct:Drains upper right thoracic cavity, right Drains upper right thoracic cavity, right

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

Empties into venous system at junction of:Empties into venous system at junction of:Right internal jugular vein.Right internal jugular vein.

Right subclavian vein.Right subclavian vein.

thoracic cavity mediastinum. mediastinum mediastinum = space between lungs. mediastinum = space...

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