Chapter 1 Flashcards
How is the mediastinum divided into compartments?
1) Four-compartment model (subdivided by thoracic plane)
2) Felson’s three-compartment model (no superior compartment)
3) Shield’s three-compartment model (prevasc-visc-paraverteb)
Where does thoracic duct go from R to L?
At T4, angle of Louis
Where does left recurrent laryngeale nerve loop around aortic arch?
At T4, angle of Louis
What is the arterial supply of the thymus?
a) Internal thoracic arteries
b) Inferior thyroid arteries
c) Superior thyroid arteries
What is the venous drainage of the thymus?
Via the posterior veins of Keynes which drain into the
a) brachiocephalic veins
b) internal thoracic veins
c) superior vena cava
d) inferior thyroid veins
What are the posterior veins of Keynes?
Venous drainage of thymus
How much of the lymphatic fluid flows via the thoracic duct into the venous system?
75%
What are the openings in the diaphragm?
T8: VCI + phrenic nerve r
T10: Oesophagus + both vagus nerves
T12: Aorta + thoracic duct + azygos vein
Where does the thoracic duct empty into?
Into venous circulation at superior aspect of the junction of the left internal jugular and subclavian veins, where it is related to the left common carotid artery and vagus nerve.
Total length of the trachea? + parts of trachea?
11-13 cm
Cervical part (5 cm) til suprasternal notch, thoracic part (6-8 cm)
How many tracheal rings?
18-22
Right main bronchus vs left?
Right is wider, shorter and more vertical
Arterial supply trachea?
Cervical: inferior thyroid arteries
Thoracic: bronchial arteries
Length of esophagus?
25 cm
Z-line
Squamocolumnar junction:
- Non-keratinising squamous epithelium
-> glandular epithelium
Most important layer to close when repairing perforations of the oesophagus?
Internal mucosal layer
2 plexi in body of oesophageal wall
A) Auerbach’s plexus / myenteric plexus (between circular and longitudinal muscular layers)
B) Meissner’s plexus / submucosal (within submucosal layer)
Why and where does perforation of oesophagus cause empyema and mediastinitis?
At level of T8: oesophagus moves to lie anterior to the descending thoracic aorta with both lateral surfaces covered by parietal pleura.
Arterial supply oesophagus?
Cervical: inferior thyroid artery
Thoracic: bronchial and oesophageal branches of descending thoracic aorta
Abdominal: left gastric and splenic arteries
Venous drainage of abdominal oesophagus?
Left gastric vein = tributary of portal system -> portosystemic venous anastomosis
Origin of phrenic nerve?
C3 - C4 - C5
Relation of phrenic to subclavian artery and IMA?
Posterior to subclavian
Medial to IMA
Vagus nerve is which cranial nerve?
10th
Where does vagus nerve enter thorax?
Behind sternoclavicular joint and brachiocephalic vein
How many paired sympathetic ganglia?
23
3 cervical
12 thoracic
4 lumbar
4 sacral
Which ganglion gives Horner’s syndrome when damaged?
The stellate ganglion. Fusion of inferior cervical ganglion and the 1st thoracic ganglion
Fissures of the lungs? left vs right?
Left: only oblique
Right: horizontal (upper one) and oblique (lower one)
Segments of the lung?
Right: 10
Left: 10
See image
Each bronchopulmonary segment is
- Roughly equal in sze
- Pyramidal in shape with apex pointing towards hilum of the lung
- Supplied by own bronchus en pulmonary artery branch; branches of vein run in inter-segmental planes
Pig bronchus anomaly?
RUL apical segmental bronchus arises from traches rather than RUL bronchus
Occurs in 3% of patients
Can make lung isolation with double-lumen tube difficult
After RUL bronchus, what is bronchus called?
Bronchus intermedius, is about 2 cm long
RML and RLL bronchus: which one anterior, which one posterior?
RML anterior
RLL posterior
Middle lobe syndrome?
Narrowing of RML bronchus due to extrinsic nodal compression
Course of RML bronchus?
Passes under RLL pulmonary artery branch
Lies between inferior part superior pulmonary vein and RML pulmonary artery branch
What must you take care of when dividing and closing bronchus of RLL?
Narrowing of RML bronchus!
What makes bronchial sleeve resection on the left more complicated?
Presence of secondary carina on the left rather than an equivalent to the bronchus intermedius
Anatomy of tracheobronchial tree?
- Conducting zone 1-16: no gas exchange
- Respiratory zonde: 17-23: gas exchange: bronchioles, alveolar ducts and alveolar sacs
Difference between bronchioles and bronchi?
Bronchioles lack cartilage, thereby making them collapsible
Pulmonary acinus
Represents a respiratory bronchiole and all of its branches
Danger zone of right pulmonary artery
After giving of RUL artery, it goes behind superior pulmonary vein, in danger of damage when encircling that structure.
What is special about artery posterior segment upper lobe right?
- Ascending pulmonary artery branch supplies it
- Is accessedby dissecting major fissure
- Sits behind lymph node station 11s, whic is between lower border of upper lobe bronchus en bronchus intermedius
Drainage lobes rights
- Upper: superior portion superior pulmonary vein
- Middle: inferior portion superior pulmonary vein
- Lower: inferior pulmonary vein
Troubleshooting encircling vein lower lobe right
Inferior pulmonary vein: drainage from apical segment may join very proximally and may be missed!
Veins forming common trunk prior to entering pericardium?
Left much more often than right (25 vs 3%)
Troubleshooting encircling pulmonary vein left
Left often common trunk before entering pericardium -> preop CT is important
Lymph node stations of the lungs
- Mediastinal nodal stations: single digit
- Pulmonary stations: double digit
See image
Which lymphatics cross the midline?
The lymphatic channels of the mediastinum
Which structures pass through the thoracic inlet?
- Subclavian artery
- Brachial plexus
- Subclavian vein
- Stellate ganglion of the sympathetic chain
- Thoracic duct
Major muscles of chest wall?
- Latissimus dorsi (n. thoracodorsalis)
- Serratus anterior (long thoracic nerve of Bell)
- Pectoralis major
- Trapezius (accessory XI nerve)
- External oblique
Which crus of the diaphragm is larger and longer?
Right is larger and longer than left, and completely surrounds the oesophagus
