anatomy

Question 1

where is the sternal angle

what is its significance

Answer 1

marks where 2nd rib articulates with sternum

very useful for counting ribs!

Question 2

where is the infrasternal angle

what is its significance

Answer 2

location for compression for CPR

Question 3

where are the two points ribs articulate with thoracic vertebrae

Answer 3

1. costotransverse joint

2. joint of head of rib

Question 4

divisions within thoracic cavity

Answer 4

left pleural cavity
right pleural cavity
(left and right pleural cavities contain the lungs)

mediastinum
( contains heart, blood vessels, airways (trachea), thorax innervation (vagus n, sympathetic trunk and phrenic nerve), thorax lymphatics (nodes, thoracic duct)

Question 5

what are the pulmonary cavities lined by?

Answer 5

lined by pleurae (double layered membranes)

• parietal pleura
• visceral pleura

parietal pleura is sensitive to pain, temperature, touch and pressure (intercostal nerves, phrenic nerve)

visceral pleura is sensitive to stretching only (autonomic nervous system)

Question 6

recesses formed by the 2 layers of pleura

Answer 6

costomediastinal recesses

costodiaphragmatic recesses

Question 7

which cervical nerves innervate diaphragm?

Answer 7

C3,4,5

Question 8

what are the 3 openings through the diaphragm?

Answer 8

1. caval opening (through central tendon)
2. oesophageal opening (through muscular part)
3. aortic opening (through tendinous arch)

Question 9

what are the three layers of intercostal muscles

Answer 9

external intercostal – elevate ribs

internal intercostal – depress ribs

innermost intercostal – depress ribs (probably)

Question 10

intercostal muscles are innervated by?

Answer 10

intercostal nerves

Question 11

blood supply of intercostal muscles?

Answer 11

intercostal arteries and veins

Question 12

what gives rise to intercostal nerves

where are the intercostal (veins, arteries and) nerves located

Answer 12

ventral rami of spinal nerves give rise to intercostal nerves

intercostal vein, artery and nerve usually sit right below rib, in between innermost and internal intercostal muscle, travel through costal groove

Question 13

arterial blood supply of intercostals

Answer 13

1. from thoracic aorta via posterior intercostal arteries and its lateral cutaneous branches
2. from subclavian arteries
   via internal thoracic arteries and anterior intercostal arteries

Question 14

Venous drainage of intercostals

Answer 14

1. posterior intercostal veins and their cutaneous branches
   drain to azygous, hemiazygous and accessory hemiazygous veins

ultimately, azygos vein drains to superior vena cava

2. anterior intercostal veins drain to internal thoracic vein and subclavian veins

Question 15

thoracic lymphatics

Answer 15

chest wall and parts of mediastinum drain first towards the

• paravertebral nodes
• parasternal nodes
• paramammary nodes

and then to
thoracic duct and
right lymphatic duct

Question 16

accessory muscles of respiration

Answer 16

anterior, middle and posterior scalenus
sternocleidomastoid
pectorals (major and minor)

Question 17

anterior, middle and posterior scalenus

functions and innervations

Answer 17

laterally bend the neck
and lift or stabilise ribs 1 and 2

innervation via cervical and brachial plexi (C4-C8)

Question 18

Definition of mediastinum

Answer 18

Medial compartment of thoracic cavity

Question 19

Is the mediastinal mobile in chest?

Answer 19

Yes

Question 20

What separates the superior and inferior mediastinum

Answer 20

Transverse thoracic plane

Question 21

What is in the superior mediastinum

Answer 21

Great vessels

• veins (brachiocephalic veins and SVC) anterior to arteries
• arteries (arch of aorta and roots of its major branches — brachiocephalic trunk, left common carotid artery and left subclavian artery)

Related nerves (vagus, phrenic nerves and cardiac plexus of nerves)

Inferior continuation of cervical viscera (trachea, oesophagus) and related nerves (left recurrent laryngeal nerve)

Thoracic duct and lymphatic trunks

Part of thymus

Question 22

What is in posterior mediastinum

Answer 22

Thoracic aorta
Thoracic duct
Lymphatic trunks
Posterior mediastinal lymph nodes
Azygos and hemiazygos veins
Oesophagus and oesophageal nerve plexus

Question 23

What is found in anterior mediastinum (smallest subdivision)

Answer 23

Loose connective tissue
Fat
Lymphatic vessels and a few lymph nodes
Branches of internal thoracic vessels

In infants and children, anterior mediastinum contains inferior part of thymus

Question 24

Pericardium

Answer 24

Fibroserous membrane that covers heart and beginning of its great vessels

Fibrous pericardium: tough external layer, protect heart against sudden overfilling

Serous pericardium: dual layered (parietal and sudden overfilling)

Question 25

Pericardial effusion

Answer 25

Passage of fluid from pericardial capillaries or pus into pericardial cavity Caused by some inflammatory diseases

Question 26

Mediastinal nerves

Answer 26

Right and left phrenic nerves | Right and left vagus nerves

Question 27

Mediastinal lymphatics

Answer 27

Mediastinal lymph nodes are found in front of aorta and alongside it Tracheobronchial nodes are located at bifurcation of trachea, and collect lymph from lungs and heart

Question 28

Position of lungs in thorax

Answer 28

Posteriorly, lungs reach below 9th pair of ribs (Pleura reaches even further, into costodiaphragmatic recess, below 11th pair of ribs Anteriorly, lungs reach to about 6th pair of ribs (Pleura to 7th rib pair)

Question 29

How are lungs divided into lobes by

Answer 29

Fissures

Question 30

How many lobes are there in the right and left lung respectively

Answer 30

Right lung has 3 lobes (superior, middle and inferior lobe) Left lung has 2 lobes (superior and inferior)

Question 31

What does the root of the lung contain

Answer 31

Blood vessels and bronchi entering and leaving the lungs on their mediastinal surface As well as lymph nodes and neural structures

Question 32

Which main bronchus is foreign material more likely to enter and get lodged in? Why?

Answer 32

Right main bronchus It is wider, shorter and more vertical than left main bronchus