Anatomy: Practical 1 - Mediastinum

Question 1

what are the divisions of the mediastinum?

Answer 1

superior

anterior

middle

posterior

Question 2

label xo

Answer 2

Question 3

At which vertebral level does the trans-thoracic plane lie?

Answer 3

T4/5 - identified at sternal angle

Question 4

is thymus in inferior or superior mediastinum?

is heart in inferior or superior mediastinum?

is trachea in inferior or superior mediastinum?

Answer 4

thymus: both

heart: inferior

trachea: superior

Question 5

where do you find the apex of the heart?

Answer 5

5th intercostal space in the mid-clavicular line

Question 6

where are the ascultation points of the heart valves?

Answer 6

The aortic area is found in the 2nd intercostal space to the right of the sternum.

The pulmonic area is found in the 2nd intercostal space to the left of the sternum.

The tricuspid area is found in the 4th intercostal space to the left of the sternum, where other right heart sounds will also be heard.

Finally, the mitral area is found in the 5th intercostal space along the mid-clavicular line, where left heart sounds can also be heard.

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Question 7

what does the superior mediastinum mostly contain?

Answer 7

mainly contains the great vessels

&

• *nerves:**
• vagus nerves descends down the neck through the carotid sheath into the thorax
• Here, it gives off the recurrent laryngeal nerves (motor to vocal cords)
• The right recurrent laryngeal nerve loops underneath the right subclavian artery and travels back up to the larynx
• The left recurrent laryngeal nerve branches off to hook under the arch of the aorta next to the ligamentum arteriosum and ascends to the larynx
• phrenic nerve

Question 8

where does the phrenic nerve enter the superior mediastinum?

Answer 8

between the subclavian artery and the origin of the subclavian vein

Question 9

label 1-6 xo

Answer 9

1: azygous vein
2: right subclavian artery
3: left brachiocephalic vein
4: left internal jugular vein
5: left common carotid artery
6: right common carotid artery

Question 10

Answer 10

Answer 11

Question 12

match these xo

Answer 12

Question 13

which nerves are 1-4?

Answer 13

1 = **right vagus nerve** (gives rise to.. the right recurrent laryngeal nerve)
2 = **right recurrent laryngeal nerve** - branches from the vagus nerve and loops under the right subclavian artery before travelling to layrnx
3 = **right recurrent laryngeal nerve** -
4 = **left vagus nerve**

Question 14

describe the path of innervation from vagus nerve to right recurrent laryngeal nerve

Answer 14

vagus nerve -> branches and loops under the right subclavian artery - > before travelling to layrnx

Question 15

label A-E

Answer 15

A = Right brachiocephalic vein
B = Left common carotid artery
C = right phrenic nerve
D = right subclavian vein
E = left vagus nerve

Question 16

what type of cartilage makes the trachea?

the trachea starts and finishes at which vertebrae levels ?

Answer 16

hyaline cartilage

starts: C6
ends: T4

Question 17

What is the bifurcation into the left and right main bronchi called?

what vert level?

Answer 17

carina

t4/5

Question 18

Answer 18

1: left common carotid artery
2: right common carotid artery

Question 19

which structures are found in anterior mediastinum?

Answer 19

not many - mostly fat and the remnant of the thymus

Question 20

which structures are found in middle mediastinum?

Answer 20

heart and its pericardial sac

Question 21

The nerve supply of the fibrous and parietal pericardium is from the X nerves?

Answer 21

The nerve supply of the fibrous and parietal pericardium is from the phrenic nerves (C3-C5).

Question 22

The pericardial sac is fused with the ….. …… of the great vessels.

Answer 22

The pericardial sac is fused with the tunica adventitia of the great vessels.

Question 23

The posterior mediastinum is located between …. (vert. levls), posterior to the pericardium and the diaphragm, and between the … ….

Answer 23

The posterior mediastinum is located between T5-12, posterior to the pericardium and the diaphragm, and between the parietal pleura of the 2 lungs.

Question 24

Which structures are found in the posterior mediastinum? (5)

Answer 24

azygos and hemizygos veins

descending aorta

oesophagus

thoracic duct

vagus nerves

Question 25

Answer 25

1 - posterior intercostal arteries 2 - anterior intercostal arteries 3 - thoracic descending aorta 4. right internal thoracic (mammary) artery 5. right subclavian artery 6 left subclavian artery 7 left internal thoracic (mammary) artery

Question 26

which vein is this?

Answer 26

azygous vein

Question 27

what is this?

Answer 27

azygos vein

Question 28

what are the two main tributaties of the azygos vein?

Answer 28

**hemiazygos vein** and the **accessory hemiazygos vein.**

Question 29

?

Answer 29

hemiazygous vein

Question 30

?

Answer 30

accessory hemiazygos vein

Question 31

name where each is found (superior, posterior, anterior and middle mediastinum) - Brachiocephalic veins - thymus: - descending aorta: - left current laryngeal nerve: - thoracic duct: - azygos vein: - left common carotid artery:

Answer 31

- Brachiocephalic veins: **superior mediastinum** - thymus: **anterior** - descending aorta: **posterior mediastinum** - left current laryngeal nerve: **superior mediastinum** - thoracic duct: **posterior mediastinum** - azygos vein: **posterior mediastinum** - left common carotid artery: **superior mediastinum**

Question 32

what are the subdivisions of the inferior mediastinum?

Answer 32

anterior, middle and posterior mediastinum

Question 33

what and where is the carotid sheath? - which structures are in it?

Answer 33

**carotid sheath:** tThe carotid sheath is one of four accumulations of deep cervical fascia or fibrous connective tissue of the neck which surrounds the great vessels of the neck. inside including the **carotid artery, jugular vein, vagus nerve, and sympathetic plexus**. It arises in the base of the neck and terminates at the skull base

Question 34

describe phrenic nerve location / which type of nerve fibres it contains. where are the nerve roots? what does the phrenic nerve cause during inhalation / exhalation?

Answer 34

The phrenic nerve originates from the anterior rami of the **C3 through C5** nerve roots and consists of motor, sensory, and sympathetic nerve fibers. It provides complete motor innervation to the diaphragm and sensation to the central tendon aspect of the diaphragm. nerve roots: **_anterior rami of C3, C4 and C5_** The **motor innervation activation** will cause the **diaphragm to contract with inspiration**, resulting in a flattened diaphragm and increased intrapleural space. During **exhalation**, the **diaphragm relaxes and returns to the dual dome shape.** The phrenic nerve also provides **touch and pain sensory innervation** to the _{mediastinal pleura and the pericardium} in addition to the intercostal nerves.

Question 35

what structures do the left and right recurrent laryngeal nerves hook under?

Answer 35

_right RLN:_ goes **under right subclavian artery** then traveling upwards. _left RLN:_ left nerve looping **under the aortic arch**

Question 36

which nerve contributs the oesphageal plexus?

Answer 36

vagus nerve

Question 37

where do u find the left and right coronary artery?

Answer 37

right coronary artery: **The right coronary artery emerges from the aorta into the AV groove.** left coronary artery: **between pulmonary trunk and left atra**

Question 38

Answer 38

Question 39

what is the crista terminalis? where found?

Answer 39

The interior surface of the **right atrium** can be divided into two parts, each with a distinct embryological origin. These two parts (sinus venarum and atrium proper) are separated by a muscular ridge called the **crista terminalis** (sinus venarum: smooth walls atrium proper: rough walls)

Question 40

what are the interatrail and interventrical septums?

Answer 40

The **interatrial septum** is a solid muscular wall that s**eparates the right and left atria.** **interventrical septum** the stout wall separating the ventricles, the lower chambers of the heart, from one another

Question 41

what is the trabeculae carnae? what is pectinate muscle? where each found?

Answer 41

The **trabeculae carneae** are rounded or **irregular muscular columns** which project from the **inner surface of the right and left ventricle of the heart**. These are different from the pectinate muscles, which are present in the atria of the heart. The **pectinate muscles** (musculi pectinati) are parallel muscular ridges in the walls of the **atria of the heart.**

Question 42

1. which three veins drain into the right atrium? 2 which vessels emerge from th aortic sinus?

Answer 42

1. superior and inferior vena cava and the coronary sinus. 2. The **left posterior aortic sinus** gives rise to the **left coronary artery.** The **anterior aortic sinus** gives rise to the **right coronary artery.** The **right posterior aortic sinus** usually gives rise to **no vessels,** and is often known as the non-coronary sinus.

Question 43

what are the 4 main valves of the heart?

Answer 43

**tricuspid valve:** located between the **right atrium and the right ventricle.** **pulmonary valve:** located between the **right ventricle and the pulmonary artery.** **mitral valve**: located between the **left atrium and the left ventricle.** **aortic valve:** located between the **left ventricle and the aorta.**