The clinical context of thoracic anatomy

Question 1

content of the superior thoracic aperture

Answer 1

The superior thoracic aperture is bounded by the following: T1, first ribs (left and right), and superior aspect of the sternum. The superior thoracic aperture allows connection of the anatomic structures of the thorax and the neck.

Question 2

what are the pleural reflections

Answer 2

The lines along which the parietal pleura changes direction as it passes from one wall of the pleural cavity to another are called the lines of pleural reflection

Question 3

structures that constitute the thoracic cage.

Answer 3

The thoracic cage (rib cage) is the skeleton of the thoracic wall. It is formed by the 12 thoracic vertebrae, 12 pairs of ribs and associated costal cartilages and the sternum.

Question 4

key divisions of tracheobroncjial tree

right upper lobe bronchus and then the bronchus intermedius

Answer 4

Trachea → carina → main bronchi → lobar bronchi → segmental bronchi → terminal bronchioles → respiratory bronchioles → alveolar duct → alveolar sac → alveoli.

Question 5

bifurcation of trachea to carina what level

Answer 5

T6

Question 6

what is th pulmonary ligament

Answer 6

reflection of the mediastinal parietal pleura below the lung root ( hilum)on each side

Question 7

innervation of the lungs

Answer 7

Pulmonary plexus at the hilum
Sympathetic and parasympathetic fibres
Symp – T2-T5 or T6
Afferent from nociceptor pain receptors
Efferent bronchodilator
Parasymp – Vagus
Afferent from stretch receptors
Efferent secretomotor to mucus glands

Question 8

is the visceral sensitive to pain

Answer 8

no but is sensitive to chemical burns

Question 9

pleural innervation

Answer 9

parietal pleur very sensitive to pain and irritation may produce either local or referred pain
spinal nerve roots are the T nerves

Question 10

costal groove at the bottom of the rib carries what

Answer 10

intercostal nerves

Question 11

If fracture is brought on by coughing – consider “pathological fracture
what are you thinking

Answer 11

metastasis

Question 12

fractures of the first rib cause damage to what

Answer 12

brachial plexus
subclavian artery
subclavian vein
pleural covering of the apex of the lung – cupula (inverted cup)
apex of the lung (pneumothorax) APEX rises above the clavicle and first rib

Question 13

thoracic outlet syndrome

Answer 13

nerve artery vein from post to ant ( subclavian and C*-T1 nerves)

compression of the nerve

The superior thoracic aperture could be obstructed by:
Extra ribs (cervical rib – inc 0.5%) above the first rib
Abnormal tight band connecting the spine to the ribs.

Question 14

who’s most likely to get thoracic outlet syndrome

pain where

complcications

investigations and examination

Answer 14

Female 30-40
Pain in the neck and shoulder
Weakness/Paraesthesia over the ulnar aspect of the hand and forearm
Loss of intrinsic ms and interossei WASTING

Complications
Axillary Vein thrombosis
Digital Ischaemia – Emboli from subclavian artery aneurysm.

Examination
Cervical Rib may be palpable, small muscle wasting hand.

Investigation
XR neck, MRI
(+/- USS arm, nerve conduction studies, venography

Question 15

flail chest

Answer 15

chest wall will look floating 
bifocal fracture(in 2 places) of 3 or more adjacent ribs - RTA

flail as loose segments of thoracic wall move in opposite directions with repsriaotry mvoemtns

Question 16

pneumothorax

Answer 16

punture parietal pleura causing lung collapse

Question 17

what is a tension pneumothorax

Answer 17

opening in the pleura acts as a one-way valve so air in on inspiration but valve closes on expiration so air cant escape
postive intra-pleural pressure collapses lung, leading to hypoxia and mediastinal shift ( and so tracheal deviation)
trachea moves/deviates to the other side

Question 18

what is a tension pneumothorax

Answer 18

opening in the pleura acts as a one-way valve so air in on inspiration but valve closes on expiration so air cant escape
postive intra-pleural pressure collapses lung, leading to hypoxia and mediastinal shift ( and so tracheal deviation)
trachea moves/deviates to the other side as air build in pleural cavity

hyper-renesont breath sounds

root of the neck injuries may result in pleural injuries ( to cupla)
in children due to having shorter necks and pleura reaching higher have a higher chance of injury

Question 19

implications of pneumothorax

Answer 19

Pleural cavity becomes a real space.
The diaphragm depressed on one side and elevated on the other.
Ribs come closer together, narrowed intercostal spaces.
Mediastinal shift away from side of pneumothorax and towards side of lung collapse.
Collapsed lung appears dense (whiter) surrounded by radiolucent (blacker) air within the pleural cavity.
This is Primary Atelectasis (Collapse of a previously inflated lung) cf Secondary where mucus plugs etc develop and cause additional collapse

tension

Hypotension& hypoxia.
Breath soundsare absent on the affected side.
Trachea deviates away from the affected side.
The thorax may also be hyperresonant.
Jugular venous distention and tachycardia may be present.

Question 20

tension pneumo management

Answer 20

Emergency thoracentesis: cannula 2nd intercostal space in Mid Clavicular Line
Then chest drain … - 5th space mid axially line

Question 21

when do you insert a chest drain

Answer 21

Pneumothorax
Haemothorax
Empyema
Possibly effusion, though more often this is simply ‘tapped

safe triangle -5th intercostal space

Question 22

order of intercostal vasculature in the rib

Answer 22

VAN

costal groove

Question 23

intercostal nerve block

Answer 23

Provides local anaesthesia of an intercostal space
Anaesthetic injected around the intercostal nerve trunk- just under the rib , above the rib is the collateral branch NAV

Note:
Complete loss of sensation is not usually achieved - overlap between adjacent dermatomes

Two or more intercostal spaces (nerves) need to be anaesthetized for complete loss of sensation at a particular region of the thoracic wall.

Question 24

haemothorax
what is it
what can it cause
how is it managed

Answer 24

Accumulation of blood and fluid in the hemithorax – compresses the lung and prevents adequate ventilation

Can cause hypovolaemic shock

Managed by simultaneous drainage and replacement of blood

Chest drain required

Rapid collection of more than 1500mL blood or 1/3 of the patients blood volume in the chest cavity.
Managed by simultaneous drainage and replacement of blood.
Thoracotomy decision is based on blood loss.

Question 25

phrenic nerve palsy

Answer 25

One common etiology of phrenic nerve injury is from surgery, primarily thoracic and cardiac surgery. The left phrenic nerve descends anteriorly between the pericardium and mediastinal pleura and can be injured while dissecting near the area of an internal thoracic artery.
The phrenic nerve can also be damaged from blunt or penetrating trauma, metabolic diseases eg diabetes, infectious causes eg Lyme disease and herpes zoster, direct invasion by tumor, neurological diseases such eg cervical spondylosis and multiple sclerosis, myopathy and immunological disease (

The diagnosis of phrenic nerve injury requires high suspicion due to nonspecific signs and symptoms including unexplained shortness of breath, recurrent pneumonia, anxiety, insomnia, morning headache, excessive daytime somnolence, orthopnea, fatigue, and difficulty weaning from mechanical ventilation. On physical examinations, findings may include decreased breath sounds on the affected side, dullness to percussion of the affected side of the chest and inward movement of the epigastrium during inspiration.