Pleura and Lungs Flashcards
Each pleural cavity is. .
. .a closed and separate space.
Visceral pleura
Serous membrane on surface of the lungs
Parietal pleura
Lines the walls of the thoracic cavity.
-The visceral and parietal pleura are continuous with one another at the root of the lung
What is the potential space between the parietal and visceral pleura called?
Pleural cavity
What system do the lungs develop from?
GI tract
- Start as components o fhte rostral GI tract
- Common precursor = endodermal tube/primitive foregut
What does the splanchnic mesoderm give rise to?
Visceral pleura
What does the somatic mesoderm give rise to?
Parietal pleura
When do lung buds develop?
5th week
What nerves carry sensation from the parietal pleura?
Phrenic & Intercostal Nerves
What are the four regions of the parietal pleura?
- Costal pleura
- Mediastinal pleura
- Diaphragmatic pleura
- Cervical pleura or pleural cupola (over apex of lung)
What nerves carry sensation from the visceral pleura?
None! Visceral pleura is insensitive
Where is the pulmonary ligament and what is it?
It drapes below the root of the lung, the thickened fusion of the visceral and parietal pleura.
How many/what lobes does the left lung have?
2
Superior & Inferior
How many/what lobes does the right lung have?
3
Superior, Middle & Inferior
Where is the costodiaphragmatic recess? What is it?
- Between costal pleura and diaphragmatic pleura of parietal pleura
- These are areas where lung tissue does not extend fully into pleural space except at full inspiration
- Potential space where abnormal fluid will accumulate
Where is the costomediastinal recess?
-Between costal pleura and mediastinal pleura of parietal pleura
Where are the phrenic nerves carried?
Between the heart and lungs in the serous coverings. They are carried in the pleuropericardial folds.
What lies anterior to the root of the lung?
- Phrenic nerve
- Pericardiacophrenic vessels (pericardiophrenic artery)
What lies posterior to the root of the lung?
-Vagus nerve
What is the pericardiophrenic artery a branch of?
Internal thoracic artery
What supplies ALL motor innervation and PART of sensory output from diaphragm?
C345 keeps the diaphragm alive! (ventral rami)
What does the phrenic nerve supply?
- Motor innervation to the diaphragm
- Sensation from central area of diaphragm
What carries sensory information from the peripheral portion of the diaphragm?
Intercostal nerves
What are the two fissures of the right lung? What do they lie between?
Superior, Middle, Inferior
- Horizontal between superior and middle
- Oblique between middle and inferior
What is the fissure of the left lung?
Oblique - lies between superior and inferior
Bc the apex of the lung extends above the clavicle. . .
. . .it is at risk of traumatic injuries to the neck such as gunshots and stabbing
What does the lingua do during respiration?
Lingua of superior lobe of left lung sides in an out of the costomediastinal recess during respiration
What are Pancoast tumors?
(Superior sulcus tumors)
-Unique lung carcinomas located specifically in apex of lung and invade through tissue contiguity the apical chest wall and the structures of the thoracic inlet (parietal pleura, 1st & 2nd ribs/vertebral bodies, lower roots of brachial plexus, upper sympathetic chain, subclavian vein and artery)
What symptoms are caused by pancoast tumors?
- Pain/numbness in arm & hand
- Horner’s syndrome
- Compression of neck structures (brachiocephalic vein, subclavian artery, phrenic nerve, vagus and recurrent laryngeal nerves)
- Bone destruction from chest wall invasion
Where does the lingual develop from?
The tongue
Why is the right lung shorter and wider?
Liver!
What are unique parts of the left lung?
Cardiac notch, lingula (anatomic equivalent of L middle lobe), oblique fissure
What does RALS tell us?
Relationship between pulmonary artery and main bronchus
-Right anterior, left superior
Where does the pulmonary artery lie on the right lung?
Pulmonary artery lies anterior to primary bronchus (RA of RALS)
What will you see at the branch of the right lung?
- R Lobar bronchi
- R Pulmonary artery
- R Superior pulmonary veins
- Hilar lymph node
- R Inferior pulmonary vein
What impressions will you see on the right lung?
- Esophagus
- Trachea
- SVC
- Esophagus
- Arch of Azygous
- Cardiac impression
Where does the pulmonary artery lie on left lung?
RALS - LS
On left lung, pulmonary artery lies superior to the primary bronchus
What will you see at the branch of the left lung?
- L pulmonary artery
- L main bronchus
- L superior pulmonary veins
- Hilar lymph nodes
- L Inferior pulmonary vein
What impressions will you see on the left lung?
- Aorta
- Heart
- Esophagus
How does the trachea split?
Trachea –> primary bronchi –> Lobar bronchi –> Segmental bronchi (~10 for each lung)
Where does the trachea split into the primary bronchi?
Around T4-5 (lying down)
T6 standing up
Where is the carina?
-Keel-shaped cartilaginous ridge at bifurcation of trachea
Bronchopulmonary segment:
That portion of lung supplies by a segmental bronchus and pulmonary artery branch
What is the significance of the trachealis muscle?
- Trachea is supported by C-shaped cartilaginous rings, open at the back
- Opening in back is filled by trachealis muscle
- As you descend, cartilage replaces the rings
What does deviation in the position of the carina indicate?
It may indicate metastasis of bronchogenic carcinoma into the tracheobronchial lymph nodes
What is the typical area in the airway where a foreign body will lodge?
Right airway
- Shorter in length
- Wider in diameter
- More vertical
Obstruction of a bronchus is the primary cause of…
Atelectasis = A collapsed and airless state of a lung. It may be acute or chronic, and may involve all or part of a lung
-Collapse of significant amount of lung may lead to mediastinal shift toward side of the collapse
What is a bronchopulmonary segment?
Smallest, functionally independent region of a lung and the smallest area of lung that can be isolated and removed without affecting other regions.
- Arteries run with Airways!
- Veins and lymphatics will drain intersegmentally around the edges
- Segments separated by connective tissue
What direction are chest radiographs typically taken?
PA
AP only if patient can’t stand
What is the difference between primary and secondary atelectasis?
Primary - failure of lung to inflate at birth
Secondary - collapse of previously inflated lung
How does inspiration causing a decrease in intra-thoracic pressure?
Normal inspiration:
- Contraction of diaphragm extends the vertical dimension of the thoracic cavity
- External intercostals widen and expand the lateral dimension while the sternum also elevates and moves anteriorly
- Increase in volume of the thoracic cavity causes a decrease in the intra-thoracic pressure
How do the pleural cavities expand during inspiration?
They experience a decrease in pressure was they expand to fill void.
-Lungs expand to fill the vacuum of the pleural cavities, and since they are open to atmospheric pressure, air moves into the lungs along its pressure gradient
What happens during expiration?
- The diaphragm relaxes, elastic recoil of the chest wall and lungs occurs.
- The volume of thoracic cavity decreases
- Increased pressure on the pleural cavities and lungs expels air
What is normal intra-pleural pressure? What does it do?
4 mmHg below atm pressure
-Acts like suction to keep alveoli inflated
What is a pneumothorax?
Entry of air into the pleural cavity is called a pneumothorax.
-As a result of air entering the cavity, pressure in the pleural cavity increases, the lung collapses and the pleural cavity becomes a real space.
What causes pneumothorax?
Traumatic punctures (bullet, stab wounds) that penetrate the thoracic wall and parietal pleura; ruptures of the lung parenchyma and visceral pleura. -Note that the pleural cavities extend into the neck
What causes a spontaneous pneumothorax?
Can be due to a rupture of a bleb or bulla on lung surface.
- Typically patient with no known lung disease
- Can occur secondary to diseases of lung
- Tall men at risk due to rapid growth spurts
- Once one has ruptured, 60% chance another will
- Some genetic predisposition
What is the common presentation of a simple/sponteneous pneumothorax?
- Tall, thin male teenager (20-40)
- Abrupt onset dyspnea
- Chest pain
- Hyperresonant percussion (exaggerated hollow sound) on affected side
- Breath sounds diminished
What is open pneumothorax?
May be caused by stab wounds often.
- Air flows easily in and out of the open wound.
- Mediastinal structures are pushed to the opposite side with inspiration but return with expiration
What is a tension pneumothorax?
Injury may be to the thoracic wall or lung tissue -Wound is covered by skin, muscle or clothing.
- Air becomes trapped in the pleural space and mediastinal structures are pushed to the opposite side
- One lung is collapsed and the other is compressed
- Trachea deviates away from the lesion
What are the clinical signs of tension pneumothorax?
Distended neck veins, shifted trachea, decreased breath sounds in both lungs, hypotension, agitation
What are the classic signs of tension pneumothorax?
- Deviation of trachea away from side of tension
- Shift in mediastinum
- Depression of hemidiaphragm
- Cardiovascular function compromised due to venous obstruction of heart
What is tube thoracostomy?
- Used for open & closed pneumothorax if large
- Chest tube inserted into 4th or 5th intercostal space in midaxillary line
- Tube is attached to suction device, allows lungs to re-expand
- Local anesthesia used
- Chest tube left in place until lung leak seals on its own, usually within two to five days
Where is a needle inserted to remove blood or other fluids?
Through intercostal space in the costodiaphragmatic recess
- Between 9th and 10th rib
- Needle must be placed above diaphragm and avoid liver and spleen
What is pleural effusion?
Increase of fluid in the pleural space
What is hemothorax?
Blood entering the pleural space e.g. from a chest wound
What location is the safest to perform a pleural tap?
9th intercostal space, mid-axillary line
