Applied Anatomy of the Thorax

Question 1

What is the function of the pectoralis major?

Answer 1

Flexion of the arm, medial rotation, adduction of the arm and accessory muscle in respiration as attached to rib cage to help lift it up

Question 2

What is the function of the pectoralis minor?

Answer 2

Accessory muscle for inspiration

Question 3

What are the pectoralis major and minor innervated by/

Answer 3

C5-T1 lateral and medial pectoral nerves

Question 4

Where is the SCM?

Answer 4

Goes from the mastoid process around the neck to the sternum

Question 5

What is the function of the SCM?

Answer 5

Helps to elevate the chest

Question 6

What innervates the SCM?

Answer 6

Accessory nerve

Question 7

Where is the serratus anterior?

Answer 7

Underside of the scapula and wraps around the chest

Question 8

What is the serratus anterior innervated by/

Answer 8

Long thoracic nerve

Question 9

What is abnormal about the long thoracic nerve?

Answer 9

It is superficial to the muscle it innervates - serratus anterior

Question 10

How do you get scapula winging?

Answer 10

If you damage the long thoracic nerve, for example if you are removing axillary lymph nodes.

Question 11

What is the function of the external intercostal muscles?

Answer 11

Elevate rib cage

Question 12

What is the function of the internal and innermost intercostal muscles?

Answer 12

Depress the rib cage

Question 13

What are the intercostal muscles innervated by?

Answer 13

Intercostal nerves

Question 14

Where is the rectus abdominis?

Answer 14

Attaches to the costal margin, runs down in front of the abdomen and attaches to the pubic symphysis

Question 15

What is the function of the rectus abdominis?

Answer 15

Forced expiration

Question 16

What is the rectus abdominis innervated by?

Answer 16

Mainly intercostal nerves but also subcostal nerve

Question 17

What direction do the intercostal muscles travel in/

Answer 17

External - hands in pockets inferiorly and anteriorly

Internal and innermost - opposite so superiorly and posteriorly

Question 18

Where do the intercostal muscles lie?

Answer 18

Between the ribs

Question 19

What does the posterior intercostal artery arise from?

Answer 19

Thoracic aorta

Question 20

What does the anterior intercostal artery and vein arise from?

Answer 20

Internal thoracic artery and vein

Question 21

Where does the neurovascular bundle lie?

Answer 21

Between the internal and innermost, in the costal groove, just inferior to the rib

Question 22

Why is thoracocentesis done?

Answer 22

To sample pleural fluid

Question 23

Where is thoracocentesis done?

Answer 23

superior to the rib, inferior part of the pleural cavity to get into the costophrenic recess where fluid will accumulate, 9th mid axillary line during expiration

Question 24

Why is thoracocentesis done in that location?

Answer 24

To avoid lung so don’t get a pneumothorax, avoid intercostal nerves

Question 25

What is a chest drain used for?

Answer 25

Pneumothorax to drain fluid out

Question 26

Where is a chest drain done?

Answer 26

In the safe triangle | 5th intercostal space in the mid-axillary line

Question 27

What is the border for the safe triangle?

Answer 27

Apex below the axilla Lateral border of the pectoralis major Anterior border of the latissimus dorsi Line superior to level of nipple

Question 28

What passes through the diaphragm and where?

Answer 28

IVC - T8 oesophagus - T10 aorta - T12

Question 29

A 53-year-old man presented to the emergency department with a glasgow coma scale score of 15 after sustaining a stab wound to the posterior neck. The MRI shows complete transection of the spinal cord at the level C7/T1. Where would he experience sensory loss? How would this affect his ability to breathe?

Answer 29

Below the level of lesion Can still breathe as major muscle diaphragm is still innervated and SCM is unaffected. Rectus abdominis and intercostal muscles not innervated but pec minor and `major will have lost some innervation so may be weaker.

Question 30

Which pleura of the lungs is more sensitive to pain?

Answer 30

Pariteal

Question 31

Why is the parietal pleura more sensitive to pain?

Answer 31

have a somatic nerve supply

Question 32

What is the parietal pleura innervated by?

Answer 32

Costal surface - intercostal nerves mediastinal surface - phrenic nerves diaphragmatic surface - intercostal and phrenic

Question 33

Why are the visceral pleura not very sensitive to pain?

Answer 33

Pain detected by sympathetic nerves which don't detect well

Question 34

What do the parietal pleura cover?

Answer 34

thoracic wall and superior surface of diaphragm

Question 35

How is a pneumothorax seen on chest x ray?

Answer 35

visceral pleura edge is seen | very black region above it

Question 36

What forms the costophrenic angle?

Answer 36

Lower edge of the parietal pleura | Extends 2 ribs lower than inferior border of lung

Question 37

A 32 year old woman sustained a gunshot wound to the right 4th intercostal space. Above the nipple. A chest radiograph demonstrated complete collapse of the lung. A further radiograph 20 mins later demonstrated an air/fluid level in the pleural cavity. How would this be seen on a x-ray?

Answer 37

Blunted costophrenic angle indicating fluid in the cavity

Question 38

Where is the apex of the lung?

Answer 38

2cm above the clavicle

Question 39

Where is the cardiac notch?

Answer 39

At the 4th rib

Question 40

At which ribs are the borders of the lungs found?

Answer 40

Inferior border - 6th rib Mid clavicular line - 10th rib Mid axillary line - 8th rib

Question 41

At which ribs are the pleura found?

Answer 41

inferior border - 8th rib Mid clavicular line - 12th rib Mid axillary line - 10th rib

Question 42

What are the differences in the right and left lung?

Answer 42

R - superior middle and inferior lobe | L - superior and inferior lobe

Question 43

What do the horizonal and oblique fissures separate?

Answer 43

Horizontal fissure separates superior and middle lobe | Oblique fissure separates middle and inferior lobe

Question 44

How do you distinguish between the pulmonary artery, pulmonary vein and bronchus?

Answer 44

Pulmonary artery is always above the vein as comes off from the heart at a higher level The bronchus has cartilage in the walls, thicker wall and has a less regular shape

Question 45

Where does the trachea bifurcate?

Answer 45

At the sternal angle (T4/T5) carina

Question 46

What is the difference between the R and L bronchus and what is the significance of this?

Answer 46

L goes up horizontal angle but R is more vertical | This means aspiration of anything is normally to R

Question 47

What is the difference between bronchioles and the bronchus?

Answer 47

Bronchioles don't have cartilage in walls but bronchus does

Question 48

What is the order of divisions from the trachea to the alveoli?

Answer 48

trachea - main bronchus - lobar bronchus - segmental bronchi - conducting bronchioles - terminal bronchioles - respiratory bronchioles - alveolar ducts - alveolar sacs

Question 49

What is a sign of hyperexpansion on an x-ray?

Answer 49

more than 7 ribs intercepting the diaphragm meaning diaphragm is compressed downwards should be 5-7 ribs intercepting diaphragm

Question 50

What are the features of emphysema?

Answer 50

Destruction of alveolar walls = permanent large air spaces Surface area reduced Elastic tissue loss so less recoil narrowed bronchioles

Question 51

Why is less elastic recoil a problem in emphysema?

Answer 51

Alveolar collapse as air gets trapped in alveoli themselves as don't get pushed out in expiration = hyperexpansion

Question 52

What are the parts of the mediatstinum?

Answer 52

Superior and inferior separated by sternal angle - T4/T5 | inferior has posterior, middle and anterior

Question 53

What does the anterior mediastinum contain?

Answer 53

Thymus remnants

Question 54

What does the middle mediastinum contain?

Answer 54

Heart and pericardium

Question 55

What does the superior mediastinum contain?

Answer 55

great vessels, oesophagus, trachea, thymus, phrenic nerve, vagus nerve, thoracic duct, recurrent laryngeal nerves

Question 56

What is the course of the recurrent laryngeal?

Answer 56

branch of the vagus which branches within the thorax and loops around the arch of aorta on the left and subclavian artery on the right, then run back up to larynx to supply vocal cords

Question 57

What does the posterior mediastinum contain?

Answer 57

``` azygos and hemi azygos vagus oesophagus thoracic duct thoracic aorta (4 BIRDS + THORACIC AORTA) ```

Question 58

What are the roots of the symp chain ganglion?

Answer 58

T1-L2 + stellate ganglion

Question 59

What does the symp do in fight or flight?

Answer 59

``` Pupil dilation Bronchodilation Cardiac acceleration Inhibition of digestion Filling of the bladder Peripheral vasoconstriction Piloerection ```

Question 60

A 75 year old life-long smoker presents with a persistent cough, hoarse voice and a pinpoint pupil in his right eye; where is tumour?

Answer 60

stellate ganglion affected as pinpoint pupil hoarse voice - recurrent laryngeal tumour must be at apex of right lung