Thoracic cavity, pleura and lungs (anat) Flashcards
What does the mediastinum contain?
Heart, large vessels, trachea, esophagus and nerves
What does the pulmonary cavities contain?
Lungs and pleurae
Thoracic cavity vs pulmonary cavity
Thoracic cavity is within the thoracic cage while pulmonary cavity is part of the thoracic cavity
Are the 2 layers of the pleura continuous?
Yes
What is the inner layer of the membrane?
Visceral pleura
What is the outer layer of the membrane?
Parietal pleura
Where is the costo-diaphragmatic recess located?
On both sides of the lung in the space btw costal and diaphragmatic pleura
Purpose of costo-diaphragmatic recess
Allows for expansion of lungs during inspiration
Clinical: use this recess to aspirate pleural fluid for diagnostic purpose
Purpose of costo-mediastinal recess
During respiratioin, anterior borders of lungs slide in and out of recess
Where does the cervical pleura extend into?
Root of the neck (2cm above clavicle) and meet behind the sternal angle at the 2nd intercostal cartilage -> continues down to 4th costal cartilage
What are the reflections of the left parietal pleura?
Diverge 1cm away from sternum at 6th costal cartilage -> curves laterally and reaches 8th rib at midclavicular line, 10th rib at midaxillary line and 12th rib at paravertebral line
What are the reflections of the right parietal pleura?
Same as the left parietal pleura except that the right layer continues to run till 6th costal cartilage behind sternum
Where is the lower limit of the lungs?
2 ribs above parietal pleura at midclavicular, midaxillary and paravertebral lines at level of 6th, 8th and 10th ribs respectively
Where is the upper limit of the lungs?
Follow outline of pleura
What kind of blood does pulmonary vein carry?
Oxygenated blood
- pulmonary vein is an exception to the rule
Which part of the lung does bronchial artery supply?
Lung tissue
What kind of blood does the pulmonary artery carry?
Deoxygenated blood
- exception to the rule
How do healthy lungs feel?
Light, soft and spongy
Which lung is larger and heavier?
Right lung
Why is the right lung shorter and wider?
Right dome of diaphragm is slightly higher
What are the 2 groups of blood vessels and what do they supply?
Pulmonary circulation -> supply lung
Systemic circulation -> supply rest of the body
Does systemic and pulmonary circulation happen simultaneously?
Yes
What does the pulmonary artery transport?
Deoxygenated blood from heart to lungs
What does the pulmonary vein transport?
Oxygenated blood from lungs to heart
What is the hilum of the lung?
Area on the mediastinal surface of the lung through which structures enter/leave the lung
What is the root of the lung?
Short tubular collection of structures that emerge at the hilum of each lung
What makes up the root of the lung?
Main bronchus, 2 pulmonary veins and 1 pulmonary artery
What surrounds the root of the lung?
Mediastinal pleura
Are the lungs inside the pleural cavity?
No, it is surrounded by the pleural sac
Which lung has a cardiac notch?
Left lung
Arrangement of vessels entering the lungs respectively (superior to inferior)?
Right
1) bronchus
2) pulmonary artery
3) pulmonary vein
Left
1) pulmonary artery
2) bronchus
3) pulmonary vein
What are the impt structures in close contact w/ the left lung in the apex region?
Thoracic spinal nerve
Sympathetic trunk
Phrenic nerve
What are the impt structures in close contact w/ the left lung in the hilar region?
Heart
Esophagus
Thoracic aorta
Arch of aorta and it’s branches
What are the branches of the arch of aorta (medial to lateral)?
1) Brachiocephalic trunk
2) Left common carotid artery
3) Left subclavian artery.
What are the impt structure in relation to the right lung?
SVC
Heart
IVC
Esophagus
Azygos vein
Phrenic vs vagus nerve
Phrenic nerves pass anterior to the root of the lungs while vagus nerves pass posterior to the root of the lungs
What does the phrenic nerve comprise of?
Motor, sensory and sympathetic nerve fibers
What does phrenic nerve provide?
Motor innervation to diaphragm
Sensory innervation to central part of the diaphragm, mediastinal and diaphragmatic pleura
Sympathetic innervation to the blood vessels
What innervates the visceral structures in the thorax?
Cardiac, pulmonary and esophageal plexuses
- contain both sympathetic and parasympathetic nerve fibers
What does the cardiac plexus innervate?
Heart
What does the pulmonary plexus innervate?
Lungs w/ visceral pleura
Trachea
Bronchioles
What does the esophageal plexus innervate?
Esophagus
Innervation of parietal vs visceral pleura and lungs
Parietal pleura receives somatic afferent innervation -> sensitive to pain
Visceral pleura and lungs receives visceral afferent innervation (autonomic) -> insensitive to pain
What is the source of innervation for the parietal pleura?
Intercostal nerves T1 - T11
Phrenic nerve (C3 - C5)
What is the source of innervation for the visceral pleura and lungs?
Pulmonary plexus
What is a dermatome?
Area of skin that is mainly supplied by a single spinal nerve where each nerve relays sensation from a particular region of skin to the brain
What is referred pain?
Pain felt at a site diff from the injured/diseased organ/body part
Which spinal nerve supplies the skin over the neck and the shoulder?
C3 and C4
Which spinal nerve supplies the mediastinal and central part of the diaphragmatic pleura?
Phrenic nerve aka C3 to C5
Why does the brain mistake pain from the internal organ for pain from the skin?
Pain pathways from the skin surface and from internal structure/organ pass very close to each other at dorsal root via ephatic transmission -> brain mistakes pain
Where does the trachea begin and end in terms of spinal level?
Begins at cervical vertebra 6 (C6) and ends at sternal angle (btw thoracic vertebrae 4 and 5)
What are tracheal rings made of and how are they connected?
Hyaline cartilage (strong and flexible tissue)
Interconnected by fibroelastic tissue
How are tracheal rings shaped?
C-shaped
Fn of tracheal rings
Maintain mechanical stability of trachea -> keeps trachea open and prevent its collapse under negative pressures of respiratory cycle
What happens to the cartilage from superior to inferior?
Gradually reduces and disappear distally -> no cartilage in the bronchioles but smooth muscle fibres relatively more
Anterior relations to the trachea
Sternum, left brachiocephalic vein, brachiocephalic trunk and left common carotid artery and arch of aorta
Posterior relations to the trachea
Esophagus, left recurrent laryngeal nerve
Right side relations to the trachea
Azygos vein, right vagus nerve
Left side relations of the trachea
Arch of aorta, left common carotid and left subclavian arteries, left vagus and phrenic nerves
How is each bronchopulmonary segment supplied and the clinical relevance?
Has their own arterial supply
Venous and lymphatic vessels pass through the intervening septae that separate the segments from each other
Can remove a segment in event of a tumor w/o affecting other segments as they have their own arterial supply
How does movement of chest wall change when a lung is collapsed?
Movement is decreased -> chest wall moves inequally
How does sound differ when you percuss different parts?
Air containing organs (i.e: lungs) -> resonant note
Solid organ (i.e: heart) -> dull note
What is heard during auscultation if there is a collapsed lung?
Nothing -> breath sounds are absent in a collapsed lung
Where to place steth to listen to the apex of the lung?
Space above the clavicle
Where to place steth to listen to the superior lobe of the lung?
Ard the 4th rib
Where to place steth to listen to the middle lobe of the right lung?
Btw 4th and 6th rib
Where to place steth to listen to the inferior lobe of the lung?
Below 6th rib
Complication with lower ribs fracture
Tear diaphragm
What is a pneumothorax?
Entry of air into pleural cavity
What does a collapsed lung indicate on a chest x-ray?
Hyperlucency and absent vascular markings
What is pleural effusion?
Accumulation of fluid into pleural cavity
What is seen on chest x-ray in the event of paralysis of right hemidiaphragm?
Right hemidiaphragm higher than the left during inspiration
What is thoracentesis?
Insertion of needle through an intercostal space into pleural cavity
Precaution to take during thoracentesis
Needle to be inserted superior to the rib, high enough to avoid damage to collateral branches
What is a bronchogram?
Radiological examination of bronchus and its branches
What is a bronchoscopy?
Examination of the bronchus by illuminated scope
