Anatomy- Superior And Inferior Mediastina

Front 1

What is contained in the mediastinum?

Back 1

all thoracic viscera except the lungs

Front 2

Where does the mediastinum extend?

Back 2

1. anteriorly- from posterior aspect of sternum
2. posteriorly- to the thoracic vertebrae
3. superiorly- to the anatomical thoracic inlet
4. inferiorly- to the diaphragm

Front 3

What line subdivides the superior and inferior mediastina?

Back 3

1. line through sternal angle and the T4/5 intervertebral disc

Front 4

What is the inferior mediastinum divided into?

Back 4

1. anterior
2. middle
3. posterior

Front 5

What is contained in the anterior mediastinum?

Back 5

1. fatty tissues
2. thymic tissues

Front 6

What is contained in the middle mediastinum?

Back 6

1. heart
2. great vessels

Front 7

What is contained in the posterior mediastinum?

Back 7

1. viscera traversing thorax and going to abdomen

Front 8

What are the retrosternal structures of the superior mediastinum?

Back 8

1. thymus
2. great veins
3. vagus and phrenic nerves

Front 9

What is thymus derived from?

Back 9

3rd pharyngeal pouch similarly to the inferior parathyroid glands

Front 10

Where does the thymus lie?

Back 10

posterior to the manubrium

Front 11

What lies on either side of the thymus and what lies posteriorly?

Back 11

1. costomediastinal recesses on either side
2. left brachiocephalic vein and aortic arch lie posteriorly

Front 12

What join to form the left brachiocephalic vein and where is this located?

Back 12

1. left jugular vein and left subclavian vein
2. posterior to the left sternoclavicular joint

Front 13

The left brachiocephalic vein joins with what to form what and where does it do this?

Back 13

1. right brachiocephalic vein
2. superior vena cava
3. 1st right intercostal space

Front 14

Where does the left brachiocephalic vein pass in relation to the 3 great branches of the aortic arch?

Back 14

anterior and superior

Front 15

What does the left brachiocephalic vein pass anterior and superior to on its way to forming the superior vena cava?

Back 15

3 great branches of the aortic arch

Front 16

What joins to form the right brachiocephalic vein and where do they do it?

Back 16

1. right internal jugular and right subclavian
2. posterior to right sternoclavicular joint

Front 17

Where does the superior vena cava enter the right atrium?

Back 17

level of the 3rd right costal cartilage

Front 18

What flows into the superior vena cava on its posterior surface as it enter the right atrium?

Back 18

arch of the azygos system

Front 19

What nerve runs with the superior vena cava until it runs into the right atrium?

Back 19

right phrenic nerve

Front 20

Where do the vagus and phrenic nerves run in the area of the superior mediastinum?

Back 20

descend posterior to the brachiocephalic veins

Front 21

Where do the phrenic and vagus nerve run in relation to the roots of the lung?

Back 21

1. phrenic nerve- passes anterior to the root of the lung
2. vagus nerve- passes posterior to the root of the lung

Front 22

Where do the esophagus and trachea lie in relation to each other?

Back 22

trachea is more anterior than the esophagus

Front 23

Where does the trachea begin (what is it below and what spinal level is it)?

Back 23

1. begins below the larynx(below cricoid cartilage)
2. at the level of C6

Front 24

What areas of the body is the trachea present in?

Back 24

1. 1/2 in neck
2. 1/2 in superior mediastinum

Front 25

At what level does the trachea bifurcate?

Back 25

T4/5 (carina)

Front 26

How does the aortic arch affect the trachea?

Back 26

inferiorly the aortic arch displaces the trachea to the right

Front 27

What structures are immediately to the right of the trachea?

Back 27

1. brachiocephalic artery
2. right vagus nerve
3. azygos arch

Front 28

What structures are immediately to the left of the trache?

Back 28

1. left common carotid artery
2. the left subclavian artery
3. left vagus nerve
4. left recurrent laryngeal nerve

Front 29

Where does the left recurrent laryngeal nerve lie?

Back 29

between the trachea and the mediastinal pleura

Front 30

Where are lymph nodes found in relation to the trachea?

Back 30

3 bifurcation angles

Front 31

Where do the lymph nodes around the trachea and its bifurcation drain into?

Back 31

1. right lymphatic duct
2. the thoracic duct

Front 32

What is contained in the cardiac plexus?

Back 32

1. sympathetic fibers
2. vagal fibers

Front 33

Where are the sympathetic and vagal fibers of the cardiac plexus located?

Back 33

1. anterior to the carina
2. inferior to the bifurcation of the pulmonary trunk and arch of aorta

Front 34

What are the extensions of the cardiac plexus and what are they made up of?

Back 34

1. R and L pulmonary plexus(cervical,cervicothoracic, and thoracic cardiac branches, anterior and posterior vagal and sympathetic nerves
2. plexus of the thoracic aorta

Front 35

Where do the preganglionic sympathetiic nerves originate?

Back 35

at T1-4 lateral horn of spinal cord

Front 36

How do the preganglionic sympathetic nerves enter the paravertebral sympathetic chain of ganglia?

Back 36

white rami communicantes

Front 37

What other areas can the preganglionic sympathetic nerves synapse as they enter the paravertebral sympathetic chain of ganglion?

Back 37

may synapse in upper ganglia or as high up as the cervical ganglia

Front 38

What do postganglionic fibers produce in the coronary arteries?

Back 38

1. tachycardia
2. vasodilation

Front 39

What strange symptom does the sympathetic innervation of the heart control in coronary arterial disease?

Back 39

paradoxical vasoconstriction of the coronary arteries

Front 40

What fibers carry visceral reflexes and visceral pain (sensory) sensations to the spinal cord from the heart?

Back 40

visceral afferent fibers

Front 41

Where are the cell bodies of the visceral sensory fibers located and where do their fibers enter the spinal cord?

Back 41

1. cell bodies located in dorsal root ganglion
2. fibers enter spinal cord at level of T1-2

Front 42

The heart's sensory fibers enter the spinal cord at the level of T1-2. Why is this important?

Back 42

1. pain due to myocardial ischemia can be referred to the T1 and T2 dermatomes of the the left arm and chest

Front 43

Where do preganglionic vagal fibers arise from?

Back 43

cell bodies in the brainstem

Front 44

How do the preganglionic vagal fibers reach the heart?

Back 44

via the R and L vagus nerves

Front 45

Where are the ganglia for the vagal fibers located?

Back 45

confined to the atria and the interatrial septum near the roots of the great vessels

Front 46

What do efferent vagal fibers produce?

Back 46

bradycardia

Front 47

Afferent vagal fibers from the heart, aorta, and great vessels are mainly for what type of reception?

Back 47

1.chemoreception
2. baroreception

Front 48

Where are the cell bodies of the vagal fibers located

Back 48

inferior ganglion of the vagus nerve

Front 49

How many great branches come off the aortic arch?

Back 49

3

Front 50

What line does the inferior aspect of the aortic arch lie on top of?

Back 50

1. line from the sternal angle through the T4/5 intervertebral disc

Front 51

Where is the aorta located in relation to the sternum?

Back 51

posterior to the right margin of the sternum

Front 52

What does the aortic arch arch over and what does it become? What level does it become this?

Back 52

1. arches over right pulmonary artery and left bronchus
2. curves to the left and becomes descending aorta
3. to the left of T5 vert. body

Front 53

What does the aortic arch lie anterior to?

Back 53

1. end of trachea
2. left recurrent laryngeal nerve(curves around anterior and inferior to the arch but ends behind it)
3. superior esophagus
4. thoracic duct

Front 54

What crosses the aortic arch anteriorly?

Back 54

1. Left vagus nerve
2. left phrenic nerve
3. left superior intercostal vein

Front 55

What part of the aortic arch do the great branches arise and what are they (right to left)?

Back 55

1. arise from superior aspect of arch
2. brachiocephalic trunk, left common carotid, left subclavian arteries

Front 56

What vessel crosses the great branches of the aortic arch anteriorly?

Back 56

left brachiocephalic vein

Front 57

What does the brachiocephalic trunk arise posterior to?

Back 57

manubrium

Front 58

Where does the brachiocephalic trunk divide and what does it divide into?

Back 58

1. divides posterior to the right sternoclavicular joint
2. divides into right common carotid and right subclavian arteries

Front 59

What does the left common carotid artery course into the head inside?

Back 59

carotid sheath

Front 60

What does the left subclavian artery arch over? Where does this happen? What does it enter after doing this?

Back 60

1. arches over apex of left lung
2. happens posterior to rib 1 costal cartilage
3. enters the axilla after doing this

Front 61

What is present on the inferior aspect of the aortic arch and what did it used to be?

Back 61

1. ligamentum arteriosum
2. used to be ductus arteriosus

Front 62

What is the purpose of the ductus arteriosus during prenatal life?

Back 62

shunts blood away from the pulmonary system

Front 63

What causes the ductus arteriosus to close?

Back 63

1. expansion of the lungs
2. a decrease in resistance in the pulmonary arterial system postnatally

Front 64

What other structure's course is the ligamentum arteriosum intimately associated with?

Back 64

1. the course of the left recurrent laryngeal nerve

Front 65

How do the vagus nerves descend in the neck?

Back 65

1. on the posterior aspect of the common carotid arteries in the carotid sheath

Front 66

Where do the vagus nerves enter the thoracic inlet?

Back 66

posterior to rib 1

Front 67

Once entering the thoracic inlet what do the vagus nerves pass anteriorly to (right and left)?

Back 67

arterial system
1. Right - right subclavian artery
2. Left- aortic arch

Front 68

Once passing anterior to the arterial system in the superior mediastinum what do the vagus nerves pass posterior to and what branches do they give out?

Back 68

1. roots of the lung
2. giving out branches to the cardiac and pulmonary plexuses

Front 69

What does the left recurrent laryngeal nerve branch from?

Back 69

1. left vagus nerve

Front 70

Where does the left recurrent laryngeal nerve pass once branching off the left vagus?

Back 70

1. passes below ligamentum arteriosum and the arch of the aorta
2. ascends between the trachea and esophagus into the root of the neck

Front 71

What does the right recurrent laryngeal nerve arise from and where does it do this?

Back 71

1. right vagus nerve
2. anterior to the right subclavian artery

Front 72

What is the course the right recurrent laryngeal nerve takes after branching off the right vagus nerve?

Back 72

1. courses under the subclavian artery and ascends into the neck

Front 73

What do the recurrent laryngeal nerves provide innervation?

Back 73

1. trachea
2. esophagus
3. larynx

Front 74

What do the phrenic nerves arise from?

Back 74

anterior rami of C3,4,5

Front 75

After entering the thoracic inlet what direction do the phrenic nerves course?

Back 75

medially

Front 76

How does the left phrenic nerve cross the left vagus nerve?

Back 76

anteriorly

Front 77

How do the phrenic nerves descend in the mediastinum?

Back 77

1. anterior to the root of the lungs (between lateral wall of the fibrous pericardium and the mediastinal part of the parietal pleura)

Front 78

What vessel is the right phrenic nerve associated with in its upper course and its lower course? Where does it pierce the diaphragm?

Back 78

1. upper course- SVC
2. lower course- IVC
3. pierces diaphragm with IVC at the margin of the fibrous pericardial attachment to the central tendon

Front 79

Where does the desending aorta start? Where does it run from there?

Back 79

1. starts on left side at T5
2. descends on the left of the vert. column posterior to the root of th left lung

Front 80

Where does the descending aorta become midline?

Back 80

at T8

Front 81

What does the descending aorta pass through and where does it do it?

Back 81

1. aortic hiatus
2. T11/12

Front 82

What joins the descending aorta at the aortic hiatus and where do they go?

Back 82

1. greater splanchnic nerves from the sympathetic trunk
2. enter the abdomen

Front 83

What are the visceral branches of the descending aorta?

Back 83

1. 1-3 bronchial arteries
2. 1-3 esophageal arteries
3. branches to pericardium and diaphragm

Front 84

What are the parietal (thoracic) branches from the descending aorta?

Back 84

1. R and L posterior intercostal arteries

Front 85

Where are the R and L posterior intercostal arteries located?

Back 85

1. from 3rd intercostal space to subcostal arteries below R12

Front 86

Where do the right posterior intercostal arteries from T3-T8 run when crossing to the right side?

Back 86

anteriorly to vert. column

Front 87

What do the posterior intercostal arteries anastomose with and where do they do it?

Back 87

1. anterior intercostal arteries and internal thoracic arteries
2. midclavicular line

Front 88

Where does the thoracic duct begin? Where is this structure located?

Back 88

1. cisterna chyli
2. posterior to the abdominal aorta, inferior to diaphragm

Front 89

Where does the thoracic duct enter the thorax? Where does it run once it enters?

Back 89

1.posterior to the descending aorta
2. stays on right side of the vert. column

Front 90

At the level of T8 where is the thoracic duct and how far does it run like this?

Back 90

1. posterior to esophagus
2. runs to T5 behind it

Front 91

What happens to the thoracic duct at T5?

Back 91

1. crosses the vert. column and enters the root of the neck on the left side

Front 92

Where does the thoracic duct terminate?

Back 92

1. at the junction between the left subclavian and left internal jugular veins

Front 93

What does the thoracic duct drain?

Back 93

1. all the lymph of the body except for the right thorax, right upper limb, and right side of head and neck

Front 94

Where does the lymph from the right thorax, right upper limb, and right side of head and neck drain?

Back 94

right lymphatic duct

Front 95

What does the azygos and hemiazygos venous system drain?

Back 95

1. the posterior thoracic wall from the 3rd intercostal space to the subcostal veins

Front 96

What side and what veins does the hemiazygos vein drain?

Back 96

1. posterior intercostal veins of the left side

Front 97

What does the hemiazygos system join with and where does it do it?

Back 97

1. azygos system
2. mid thoracic region passing anterior to the vertebral column

Front 98

Where does the azygos system run?

Back 98

1. ascends on right side of vert. column
2. arches over right bronchus to enter the posterior aspect of superior vena cava at level of costal cartilage 3

Front 99

What does the azygos vein drain into and at what level does it do this?

Back 99

1. posterior aspect of the superior vena cava
2. at level of costal cartilage of rib 3

Front 100

What do the right superior intercostal veins drain? What do they drain into?

Back 100

1. 2nd, 3rd and 4th right intercostal spaces
2. azygos vein

Front 101

What does the left superior intercostal vein drain into? What path does it take to do it?

Back 101

1. left brachiocephalic vein
2. by crossing the anterior aspect of the aortic arch

Front 102

What do the highest posterior intercostal veins drain and where do they drain into?

Back 102

1. drain 1st intercostal space
2. drain into brachiocephalic veins

Front 103

What do the anterior intercostal veins drain into?

Back 103

1. internal thoracic veins

Front 104

Where does the esophagus begin(also what level) and where does it pierce the left dome of the diaphragm?

Back 104

1. begins posterior to the pharynx (C6)
2. pierces diaphragm at level of costal cartilage of rib 7 (T10)

Front 105

Where is the esophagus constricted?

Back 105

1. C6(upper esophageal sphincter-voluntary)
2. T2/3 (crossing of aortic arch)
3. T4/5 (crossing of left primary bronchus)
4. T10 (diaphragm)

Front 106

What are the distances associated with the areas of esophageal constriction in relation to the incisor teeth?

Back 106

1. C6 (15cm)
2. T2/3 (22cm)
3. T4/5 (27.5cm)
4. T10 (40 cm)

Front 107

What vertebral levels does the esophagus lie anterior to?

Back 107

C7-T8

Front 108

What direction does the esophagus swing in the lower thorax and what structure does it run in front of?

Back 108

1. left
2. descending aorta

Front 109

What is the esophagus anterior to in the midthoracic region?

Back 109

1. thoracic duct
2. right posterior intercostal arteries (T3-T7)
3. azygos and hemiazygos systems

Front 110

Where is the trachea in relation to the esophagus and at what levels does it lie this way?

Back 110

1. anterior
2. from C7-T4

Front 111

What part of the heart does the esophagus lie posterior to when it crosses behind the heart?

Back 111

1. left atrium

Front 112

What is the cricopharyngeus?

Back 112

1. superior esophageal sphincter (voluntary muscle)

Front 113

What is the inferior esophageal sphincter under the control of?

Back 113

1. vagus (opens)
2. sympathetic fibers (closes)

Front 114

In the cervical region, where do the recurrent laryngeal nerves lie?

Back 114

1. between the trachea and esophagus

Front 115

Inferior to the root of the lung, where do the right and left vagus nerves lie?

Back 115

1. right- posterior to esophagus
2. left- anterior to esophagus

Front 116

Branches from the right and left vagus nerves form what near the esophageal hiatus?

Back 116

1. anterior and posterior esophageal plexuses

Front 117

Once crossing through the diaphragm what are the vagus nerves renamed?

Back 117

1. anterior and posterior gastric nerves

Front 118

What do the vagal nerves do for the esophagus?

Back 118

1. induce peristalsis
2. secretomotor (promote secretion) to mucous glands

Front 119

Sympathetic nerve branches act how on blood vessels?

Back 119

1. vasomotor (control diameter of the lumen of blood vessels)