14 - Superior and Posterior Mediastinum

Question 1

Note: L brachiocephalic v. crosses trachea

Answer 1

anteriorly

Question 2

Vagus Nerves (CN X) & Phrenic n.: Pass through the

Answer 2

thoracic inlet between a vein and artery

Question 3

Vagus Nerves (CN X): Descends posterior to

Answer 3

root of lung

Question 4

Vagus Nerves (CN X): Parasympathetic innervation to

Answer 4

thorax (& abdomen)

Question 5

Phrenic Nerves (C3-C5): Descends anterior to

Answer 5

root of lung

Question 6

Phrenic Nerves (C3-C5): Somatic innervation to

Answer 6

diaphragm

Question 7

Mediastinal Divisions anterior to

Answer 7

vertebral bodies

Between mediastinal pleura of both lungs

Question 8

The mediastinum is subdivided into 4 smaller regions:

Answer 8

Superior
Inferior
-Anterior
-Middle
-Posterior

Question 9

Extends from the

mediastinum

Answer 9

thoracic inlet to diaphragm & from sternum to 12th thoracic vertebra

Question 10

Infection may spread from Retropharyngeal Space(1) into

Answer 10

Danger Space(2)

Question 11

Descending aorta: Lies just

Answer 11

L of esophagus

Question 12

Descending aorta: Gives rise to

Answer 12

posterior intercostal aa supplying thorax

Question 13

Descending aorta: Supplies branches to

Answer 13

trachea, bronchi & esophagus

Question 14

Chylothorax = accumulation of

Answer 14

lymph in pleural cavity

Question 15

Chylothorax results from

Answer 15

Results from torn or leaking thoracic duct

Question 16

Chylothorax Often from

Answer 16

lymphoma or trauma during thoracic surgery

A type of pleural effusion visible on chest films

Question 17

Superior mediastinum above

Answer 17

above the sternal angle (= posterior to the manubrium) & T4-T5 IV disc

Superior extent is an oblique plane passing from the jugular notch upward and posteriorly to the superior border of T1 vertebra.

Question 18

Anterior mediastinum

between

Answer 18

sternum & pericardium

Question 19

Middle mediastinum

contains

Answer 19

pericardium & related structures

Question 20

Posterior mediastinum

between

Answer 20

pericardium & T5-T12 vertebrae

Question 21

Thymus Gland: Posterior to the

Answer 21

Manubrium

Question 22

Thymus Gland: Lies anterior to

Answer 22

brachiocephalic vv.

Question 23

Thymus Gland: Prominent & active in childhood prior to

Answer 23

puberty

T cell maturation

Question 24

Thymus Gland: Functionally

Answer 24

inactive & atrophies in adults

may appear as a fatty mass in older individuals

Question 25

Aortic Arch: Begins & ends at

Answer 25

same level = sternal angle or T4-T5 | 3 portions of aorta

Question 26

Aortic Arch: Arches over

Answer 26

L main bronchus & pulmonary trunk

Question 27

Aortic Arch: Gives rise to

Answer 27

3 great aa. before descending brachiocephalic trunk L common carotid a. L subclavian a.

Question 28

Trachea: Descends immediately

Answer 28

anterior to esophagus

Question 29

Trachea: Bifurcates at

Answer 29

inferior limit of superior mediastinum | Carina

Question 30

Trachea: Numerous lymph nodes found at the

Answer 30

carina

Question 31

Clinical Notes: Carina: Foreign bodies usually

Answer 31

aspirated into R main bronchus

Question 32

Clinical Notes: Carina: Shorter and wider than

Answer 32

L main bronchus

Question 33

Clinical Notes: Carina: R also more

Answer 33

vertically oriented than L

Question 34

Clinical Notes: Carina: Carina usually positioned

Answer 34

L of median plane

Question 35

Esophagus: Descends immediately

Answer 35

posterior to trachea

Question 36

Esophagus: Pierces diaphragm at

Answer 36

esophageal hiatus

Question 37

Esophagus: Arteries arise from

Answer 37

thoracic a., bronchial aa. & ascending L gastric a.

Question 38

Esophagus: Venous drainage via

Answer 38

azygos, hemiazygos & L gastric vv.

Question 39

Esophagus: Lymphatics to

Answer 39

posterior Mediastinum

Question 40

Clinical Notes: Esophageal Hiatus: Stomach may herniate thru

Answer 40

esophogeal hiatus = hiatal (hiatus) hernia

Question 41

Clinical Notes: Esophageal Hiatus: Type I:

Answer 41

sliding hiatal hernia stomach slides freely into thorax most common often asymptomatic

Question 42

Clinical Notes: Esophageal Hiatus: Type II:

Answer 42

paraesophageal hernia fundus often fixed in position risking gastric blood supply

Question 43

Posterior Mediastinum

Answer 43

``` Esophagus & esophageal plexus Azygos system of vv. Descending aorta Thoracic duct Thoracic splanchnic nn ```

Question 44

Esophagus & Esophageal Plexus: Vagus nn join to form

Answer 44

plexus around esophagus

Question 45

Esophagus & Esophageal Plexus: near diaphragm plexus reforms

Answer 45

vagal trunks

Question 46

Esophagus & Esophageal Plexus: L Vagus n. =

Answer 46

anterior vagal trunk

Question 47

Esophagus & Esophageal Plexus: R Vagus n. =

Answer 47

posterior vagal trunk | due to rotation of gut during development

Question 48

Esophagus & Esophageal Plexus: both trunks pass thru

Answer 48

diaphragm with esophagus

Question 49

Azygos System of Veins: Provides venous drainage for

Answer 49

thorax

Question 50

Azygos System of Veins: Azygos v. - drains

Answer 50

intercostal vv from R side of thorax

Question 51

Azygos System of Veins: Hemiazygos & accessory hemiazygos vv. =

Answer 51

drains L thorax | these both drain to azygos v.

Question 52

Azygos System of Veins: Azygos v. arches over

Answer 52

R superior bronchus to drain into SVC

Question 53

Thoracic Duct: Posterior to

Answer 53

esophagus & anterior to vertebral bodies

Question 54

Thoracic Duct: Located between

Answer 54

azygoes v. & descending aorta (thorax)

Question 55

Thoracic Duct: Passes thru diaphragm with

Answer 55

descending aorta

Question 56

Thoracic Duct: Drains lymph from

Answer 56

entire body below diaphragm

Question 57

Thoracic Duct: Enters venous angle between

Answer 57

L subclavian v. & L IJV

Question 58

Symp. Trunks are \

Answer 58

lateral of vertebral bodies & pass post. to diaphragm (or thru crura) to enter abdomen

Question 59

2 types of branches from ganglia:

Answer 59

1st – postgang. symp. To thoracic viscera 2nd - preganglionic symp. innervate the abdomen (not thorax) -Greater splanchnic nn. -Lesser splanchnic nn. -Least splanchnic nn.

Question 60

Thoracic Autonomic Nerves: Symp – originate from

Answer 60

T1-T5

Question 61

Thoracic Autonomic Nerves: Parasymp – originate from

Answer 61

vagus

Question 62

Vagus, T1-5 Commingle to form

Answer 62

thoracic plexuses cardiac pulmonary esophageal

Question 63

Somatic NS =

Answer 63

voluntary system to skin & mm.

Question 64

Autonomic NS =

Answer 64

involuntary system to viscera & vessels | Note: ANS controls visceral functions

Question 65

Trachea ends at

Answer 65

T6