session 12
Terms
undefined, object
copy deck
- mediastium basics
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covered by mediastinal pleura on each side
contains thoracic viscera and structures except the lungs
borders= superior thoracic aperture, diaphragm, sternum/costal cart., thoracic vert bodies.
flexible-hollow w/ loose connective tissue - superior mediastinum
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sup to transverse thor plan-passes sternal angle and IV disk of T4,T5
CONTAINS:
1 thymus gland
2 superior vena cava
3 brachiocephalic veins
4 arch of aorta and roots of its branches
5 trachea
6 esophagus
7 vagus and phrenic N's - ant mediastium
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smallest, b/w f/b: body of sternum and pericardium. T/B: sup medias. and diaphragm
CONTAINS:
1 lymph nodes
2 branches of internal thoracic art.
3 inf part of Thymus gland(in kids and rare cases) - middle medias.
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Contains:
1 heart and roots of great vessels
2 cardiac plexus
3 phrenic nerve - post. medias.
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sourounded by: ant side of T5-T12, pericardium, diaphragm, parietal pleura of each lung
CONTAINS:
1 thoracic aorta
2 thoracic duct
3 esophagus
4 esophageal plexus
5 lower end of trachea
6 azygous and hemiazygous veins
7 lymph nodes
8 thoracic sympathetic trunks
9 thoracic splanchnic nervs - thoracic aorta- in post medias.
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ORIG: from arch of the aorta, begins on left side of inf border of T4 body.
COURSE: descends on anterio-left side of T5-T12. As it descends it approaches the medial plane and desplaces the esophagus to the right.
END: enters abdomen through the aortic hiatus in diaphragm - esophagus-in post. mediast
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-descends in passing post and right of arch of the aorta, and post to pericardium and left atria
-then deviates left and passes through esophagial hiatus in diaphragm at level of T10, ant to aorta
*constitutes primary posterior relationship of base of heart.
*compressed in thorac part by:1)aortic arch 2)left main bronchus 3)diaphragm - Thoracic duct-in post medias.
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largest lymph channel in body
ORIG: (from chyle cistern) ascends into thorax through aortic hiatus b/w: thoracic aorta, azygous vein, esophagus, vert bodies
COURSE: ascends b/w thoracic aorta(L), azygos(R), esophagus(A), vert bodies(P)
*at T4,T5,orT6-crosses to left (post to esophagus) - Thoracic Aorta (branches from sup to inf) See table 1.6 (p.145)
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BRONCHIAL-1 right and 2 small left, supply:trachea, bronchi, lung tissue, lymph nodes
ESOPHAGEAL-2branches supply middle 1/3 of esophagus
POSTERIOR INTERCOSTAL-9 pairs to 3rd-11th intercostal spaces
SUBCOSTAL-1 pair that enters abdomen, end of series of post. interco. arts.
SUPERIOR PHRENIC-pass to post surf of diaphragm and anastomose w/ musculophrenic and pericariophenic branches of internal thoracic art. -
azygos system P. 155
basics and comm w/ other veins -
-drain back and thoracoabdominal walls and mediastinal viscera(much variation)
-Azygos vein arches over sup aspect of rt. main stem bronchus to join SVC
COMM:
Posterior intercostals Vs.-dump into azy v. from dorsal wall
Bronchial V.-into azy V.,sometimes lefts enter accessory hemiazy V.
Esophageal V.-into Azy V.
Ascending Lumbar Vs.-forms jxn at which hemiazy Vs. start
Renal Vs.-??? - Azygos Vein
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-forms collateral pathway b/w IVC and SVC
-dranis post walls of thorax and abdomen
-ASCENDS-just right of bodies T12-T5
COMM W/: post intercos. Vs, vertebral venous plexus(drain back, vert, structures of vert canal), mediastinal, esophageal, bronchial Vs - hemiazygous V
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ascends on left side, post to thoracic aorta to T9 where it crosses to rt. (post to thor aorta,thor duct, and esophagus) and joins azy V.
RECIEVES-inferior 3 posterior intercos. Vs., inf. esophageal Vs. several small mediastnal Vs. - Accessory Hemizygous V
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DESCENDS on Left side from 4th or 5th intercos space, crosses to rt at T7orT8 to enter azy V (sometimes the hemiazy)
RECIEVES- Vs from 4th-8th intercos spaces - alt route to heart
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In event of obstruction of IVC, the drainage of thoracic abdominal and back regions can be rerouted through The Azygos system
?-out the blocked SVC or IVC through intercostal, azygos system, to func SVC or IVC - alt. arterial route in thorax
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if Descending aorta is blocked: Collatera Arterial Circulation is established. Blood flows: down in internal thoracic artery, ant,sup,and post intercos arts. all participate, Posterior intercostal arts. return blood to aorta distal to obstruction
*these vessels-greatly increased B.P. and get quite enlarged - Thoracic duct
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-largest lymph channel
-Ascends through thorax and (usually) empties into jxn of left internal jugular and left subclavian veins (venous left angle)
-often beaded b/c of many valves
-Drains lymph from all of body except upper rt. quadrant (rt lymph duct does that)
-Variation common b/c sup part represents orig left member of a pair of vessels in embryo - gray vs. white rami communicans
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BOTH:GVE,ANS,sympathetic. conn.-sympathetic chain ganglion w/ initial part of ventral primary rami
DIFF: GRAY:post gang (exit symp chain gang), all along symp chain WHITE:pregang (enter scg) ONLY T1-T12 - splanchnic Ns
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-sends Visceral E and A fibers to Viscera of body cavities
LOWER THORACIC SPLANCHNIC Ns:(supply viscera inf to diaphragm, presynaptic from T5-T12)
-Greater splanchnic N-from 5th-9th thor symp gang, perforates crura of diaphragm or passas in aortic hiatus, ends in celiac gang
-Lesser splanc N-from 10-11thor gang, pierces crura of diaphragm ends in aorticorenal gang
-Least splanc N-from 12thor gang, pierces crura of diaph, ends in gang of the renal plexus - thoracic sympathetic trunks
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-in continuity w/ cervical and lumbar symp thunks
-lie against heads of ribs in sup part of thor, costovertbral joints in midthoracic, sides of vert bodies in inf thorax