The clinical context of thoracic anatomy Flashcards
content of the superior thoracic aperture
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.
what are the pleural reflections
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
structures that constitute the thoracic cage.
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.
key divisions of tracheobroncjial tree
right upper lobe bronchus and then the bronchus intermedius
Trachea → carina → main bronchi → lobar bronchi → segmental bronchi → terminal bronchioles → respiratory bronchioles → alveolar duct → alveolar sac → alveoli.
bifurcation of trachea to carina what level
T6
what is th pulmonary ligament
reflection of the mediastinal parietal pleura below the lung root ( hilum)on each side
innervation of the lungs
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
is the visceral sensitive to pain
no but is sensitive to chemical burns
pleural innervation
parietal pleur very sensitive to pain and irritation may produce either local or referred pain
spinal nerve roots are the T nerves
costal groove at the bottom of the rib carries what
intercostal nerves
If fracture is brought on by coughing – consider “pathological fracture
what are you thinking
metastasis
fractures of the first rib cause damage to what
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
thoracic outlet syndrome
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.
who’s most likely to get thoracic outlet syndrome
pain where
complcications
investigations and examination
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
flail chest
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
pneumothorax
punture parietal pleura causing lung collapse
what is a tension pneumothorax
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
what is a tension pneumothorax
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
implications of pneumothorax
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.
tension pneumo management
Emergency thoracentesis: cannula 2nd intercostal space in Mid Clavicular Line
Then chest drain … - 5th space mid axially line
when do you insert a chest drain
Pneumothorax
Haemothorax
Empyema
Possibly effusion, though more often this is simply ‘tapped
safe triangle -5th intercostal space
order of intercostal vasculature in the rib
VAN
costal groove
intercostal nerve block
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.
haemothorax
what is it
what can it cause
how is it managed
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.
phrenic nerve palsy
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.
