Lungs & Associated Structures Flashcards
What is the pleura?
Serous membrane that produces fluid that allows for lubrication and attaches lungs to inner surface of thoracic cage
**A dysfunctional pleura: stiffened pleura doesn’t allow lungs to expand –> no oxygen –> difficulty breathing (pneumothorax, hemothorax etc.)
Pleura is made up of how many parts?
3 parts form an envelope between lungs and the chest wall.
1) “Parietal pleura”: lines inside chest wall and part of diaphragm
2) “Visceral pleura”: lines lungs and adherent to all its surfaces
3) “Pleural space”: between visceral and parietal, also known as the “pleural cavity” containing the pleural fluid
Describe the lungs?
Paired, cone-shaped organs in the thoracic cavity
- Separated by the heart and other mediastinum structures
- Extend from diaphragm inferiorly to just above clavicles superiorly
- *In COPD, emphysema, or uncontrolled asthmatics -> lungs are hyperinflated/hyperextended superiorly above clavicles (when you put a needle in subclavian line you can puncture the lung)
- *Clavicle fractures can also injure the lung
- Anterior, lateral and posterior boundaries of the lung: pleura, muscles, and ribs of the thoracic cage
What is the hilum?
The medial root of the lung where the airway, blood vessels and lymphatic enter the lung
What is the anterior border of the apex of the lung?
3-4 cm above the inner 1/3 of clavicles
How many lobes does each lung have? How many fissures separate each?
- Right lung: 3 lobes (upper, middle, lower); shorter due to liver, 2 fissures separate the lobe areas (oblique and horizontal fissures)
- Left lung: 2 lobes (upper and lower); narrower due to heart; 1 fissure (oblique fissure)
Where are the lungs best auscultated?
- Better auscultated posteriorly, but right middle lobe is not auscultated posteriorly
- Base areas: T10
- “Diaphragmatic excursion”: area between T10 and T12; listening for hollow sound (telling you there’s air between cavity) -> percuss for hollow sound lower down so you can see how far down the diaphragm pulls that lung on deep inspiration
When auscultating the anterior chest what lung sounds will you hear? What areas will you auscultate?
Anterior has mostly upper lobe and very little lower lobe (and middle lobe from right lung)
- RUL and LUL apex just superior to clavicle
- RUL base at medial horizontal fissure @ 4th rib and lateral horizontal fissure/lateral oblique fissure @ 5th rib midaxillary line
- Right medial oblique fissure (between bases of RML and RLL) @ 6th rib midclavicular line
- Left oblique fissure (between bases of LUL and LLL) @ 6th rib midclavicular line
When auscultating the posterior chest what lung sounds will you hear? What areas will you auscultate?
Posterior has mostly lower lobe (no right middle lobe)
- RUL and LUL oblique fissures at T3
- RLL and LLL at T10-T12
Where will you auscultate laterally?
- RUL: spinous process of T3
- RML: 5th rib midaxillary extending anterior-laterally to 4th rib
- RLL: 6th rib midclavicular line
- LUL: spinous process of T3
- LLL: 6th rib midclavicular line
How are the lungs supplied with blood?
Dual supply:
1) Bronchial supply: arises from superior thoracic aorta or aortic arch -> supplies bronchi, airway walls and pleura
2) Pulmonary supply: enter at hila & branch with airways
What is the trachea? What is alveoli and what does it do?
- Trachea connects the larynx to 2 principle bronchi (left and right bronchus)
- Alveoli: terminal branches of 2 bronchioles, within it is the capillary system (where gas exchange occurs)
- *if airway constricted the quickest way to open up bronchiole trees is through inhalation therapy
- *inhaled objects generally found in RT-bronchus due to straighter pathway (listen to LT first for comparison, if decreased breath sounds do not ask pt. to breathe deeply)
Describe the lower respiratory tract.
Intralobular bronchiole -> terminal bronchiole -> respiratory bronchiole -> alveolus -> alveolar duct -> alveolar sac -> alveoli
- contains a lot of smooth muscle
- *any disease of smooth muscle (stiffening) -> bronchiole tree will be constricted -> can’t expand -> less airflow
What kinds of respiratory tract infections occur in our population?
175 episodes of respiratory infection
- URT (59.4%) -> lungs CLEAR (common cold/rhinitis, acute otitis media, tonsillitis, sudden rash)
- LRT (40.6%) -> lungs will have wheezing/rhonchi, rales (wheezing in asthma & cardiac problems, pneumonia, bronchiolitis/secondary pneumonia, atelactasis-affects alveoli and seen on x-ray as skinny white line extending across lung, whooping cough-paroxysmal cough that is highly contagious and has extremely high morbility)
Where does the trachea begin and where is it located?
- Anterior to esophagus, 10-11 cm long
- Begins at cricoid cartilage
- Bifurcates just below sternal angle into RT-main stem bronchus (shorter and straighter, where you place an intubation) and LT-main stem bronchus
- Trachea and bronchi provide passage for air to get into lungs from environment
What is the cardiac notch?
The indentation in the medial part of the left lung to accommodate the heart
What is the anterior border of the base of the lung?
Rests on the diaphragm at the level of the 6th rib at mid-clavicular line
What is the lateral borders of the lungs?
Extend from the apex of the axilla to the 7th-8th ribs
What is the posterior borders of the lungs?
Apex is at C7 and the base is at T10 (T12 on deep inspiration)
Where would you listen to lung sounds on a patient with CHF?
Posteriorly and B/L -you can hear fluid best in the posterior regions. You will often hear bibasilar rales or absent lung sounds in the lung bases when fluid is present. Important to ausculate B/L because B/L-pleural effusion is common
What is a possible respiratory complication of an enlarged heart?
Pneumonia - due to the decreased air exchange that an enlarged heart causes
How many lobar bronchi does the right lung contain?
3 - right superior, right middle and right inferior lobar bronchi (for each lobe)
How many lobar bronchi does the left lung contain?
2 - left superior and left inferior lobar bronchi (for each lobe)
What is the trachea?
10-11 cm long tube anterior to esophagus, that connects to the two principal bronchi
Where does the trachea begin and bifurcate?
Begins at cricoid cartilage and bifurcates just below sternal angle
What is the function of the trachea and bronchial tree?
Provide passage for air to get into lungs from environment
What is dead space?
The part of tidal volume that is not involved in gas exchange (around 150 mL in a healthy person); excess capacity for lungs to inflate
What are the 4 functions of the respiratory system?
1) Supplies oxygen for energy production
2) Removes CO2 and waste products for energy production
3) Homeostasis (acid-base of arterial blood)
4) Heat exchange
How does respiration maintain pH of blood?
Supplying O2 and removing CO2
What are normal ranges of arterial blood gases?
pH = 7.34-7.45 pCO2 = 35-45 mmHg pO2 = 80-100 mmHg SaO2 = 94-98%
How do lungs adjust the amount of CO2 in the body?
Respiratory rate: hypoventilation (shallow/slower breathing) and hyperventilation (faster breathing)
- hyperpnea = increased depth and rate of breathing
- tachypnea = shallow, increased rate of breathing
- hypopnea = shallow breathing
- bradypnea = slow breathing
What should you do when someone is hyperventilating due to anxiety?
Give them a paper bag to breathe into and allow them to recycle their own CO2, since they will be blowing off too much CO2
-CO2 controls respiration!
Where does control of respiration come from?
The pons and medulla of the brainstem
What is the stimulus to breathe in a normal person?
Hypercapnia - an increase in the level of CO2 in the blood and CSF
What are the muscles of inspiration?
- External intercostal muscles: elevate the ribs and expand the width of the thoracic cavity (in quiet and forced inspiration)
- Interchondral part of the internal intercostal muscles: elevates the ribs
- Diaphragm: domes descend, increasing length of thoracic cavity; elevates lower ribs
- Accessory/secondary muscles: sternocleidomastoid (elevates sternum), scalenes (elevate and fix 1st and 2nd ribs), trapezius, serratus anterior, pectoralis major/minor, latissmus dorsi
What are the muscles of inspiration?
- External intercostal muscles: elevate the ribs and expand the width of the thoracic cavity (in quiet and forced inspiration)
- Interchondral part of the internal intercostal muscles: elevates the ribs
- Diaphragm: domes descend, increasing length of thoracic cavity; elevates lower ribs
- Accessory muscles: sternocleidomastoid (elevates sternum), scalenes (elevate and fix 1st and 2nd ribs), trapezius, serratus anterior, pectoralis major/minor, latissmus dorsi
What are the muscles of expiration?
- Quiet breathing: expiration results from passive recoil of lungs and rib cage
- Active breathing: Internal intercostal muscles (except interchondral part) lowers ribs and decrease width of thoracic cavity; Abdominal muscles (rectus abdominis, internal/external obliques, transverse abdominis) depress lower ribs and compress abdominal contents, thus pushing up diaphragm
What happens when the diaphragm contracts?
The superior-inferior dimension of the thoracic cavity is increased
What is pectus excavatum?
Posterior depression of the sternum and costal cartilage due to overgrowth of the costal cartilage
**3.5 : 1 male-to-female ratio
Are other thoracic structures affected with pectus excavatum?
No - the 1st, 2nd ribs and manubrium are in the normal position
What are the musculoskeletal abnormalities associated with pectus excavatum?
Scoliosis, kyphosis, myopathy, Marfan’s syndrome, Cerebral palsy
What are the symptoms of pectus excavatum?
Decreased exercise tolerance Fatigabilitiy Dyspnea on exertion Sternal pain Multiple URIs Palpitations **most common complaint is cosmetic
What is pectus carinatum?
Anterior protrusion of the sternum
- “pigeon chest”
- less common that pectus excavatum
What is Poland’s syndrome?
Congenital absence of pectoralis major/minor muscles, ribs, breast abnormality, chest wall depression and syndactylyl (2 or more digits fused together), brachydactylyl (shortening of fingers and toes due to unusually short bones, usually 4th digit; inherited condition–what you see in hands you see in feet), or absence of phalanges
What is the thoracic outlet?
The space through which the subclavian artery, subclavian vein and the brachial plexus pass to the upper limb
- boundaries: 1st rib, clavicle, scalene muscles
- sx develop when these structures are compressed at the outlet
What is a cervical rib?
An accessory rib which is not normally present - when present, it can cause compression of important structures in the thoracic outlet
What are the neurogenic symptoms of a cervical rib in TOS?
95% incidence - ulnar nerve C7-T1 usually affected
- Sympathetic -> Raynaud’s phenomenon (usually B/L because it is systemic, if unilateral suspect TOS)
- Peripheral -> pain, paresthesias, motor weakness
What are the vascular symptoms of a cervical rib in TOS?
5% incidence - prolonged compression and trauma
- Subclavian vein -> edema, venous distention, Paget-Schroetter syndrome -> UE DVT in the axillary/subclavian veins
- Subclavian artery -> intimal injury -> stenosis, thrombosis -> post-stenotic dilation/aneurysm -> distal micro-embolisation
Which ribs are most commonly injured?
5th-9th rib (anterior and lateral)
How do rib fractures present?
- History of single traumatic blow
- Pain over fx site (pinpoint pain; diffuse pain would be a pulmonary problem)
- Pain with deep inspiration, coughing, sneezing, movement of torso
What is subcutaneous emphysema?
Pockets of air over fractured areas directly under the skin (feels like wax paper, when you touch the area crackles); seen with blunt force trauma
What is the most common cause of chest pain?
Tietze syndrome = costochondritis (inflammation of costochondral cartilage where ribs join sternum); referred pain midclavicular line 3rd and 4th ribs down to back
-MOI: hyperflexion, horizontal abduction
What is a pneumothorax?
Accumulation of air in the pleural cavity
- Must evaluate because lung cannot expand
- Treatment: put in chest tube
- Clinical signs: apprehension/agitation, cyanosis, diminished breath sounds, distended neck veins/tracheal deviation
- Palpation: trauma induced -> point tenderness
- Vital signs: labored, shallow respirations, BP decreases rapidly
What is a spontaneous pneumothorax?
ATRAUMATIC lung rupture -> air within pleural cavity -> pressure increases
- Re-inflate lung via chest tube to get air and fluid out to create negative pressure so the lungs can expand
- Diagnosis dependent on signs/symptoms = rare (SOB)
- Contributing factors = tall/thin, family hx, sports related, weight lifting, football injuries, simple jogging
- Localized (side of affected lung and can radiate to shoulder, neck and back)
What is primary and secondary spontaneous pneumothorax?
- Primary spontaneous pneumothorax = bleb (outpocket of air in lungs bursts especially in smokers, COPD)
- Secondary spontaneous pneumothorax = subcutaneous emphysema
What is a tension pneumothorax?
TRAUMATIC; one way valve is created from blunt or penetrating trauma
- Air can enter but cannot leave pleural space –> increases intrathoracic pressure –> lung collapses –> increases pressure on mediastinum
- Pressure will eventually collapse superior and inferior vena cava –> loss of venous return –> decreased BP
- Stabilize by ecclusive closing dressing so air cannot get in
What is a hemothorax?
Blood enters pleural space –> lung on affected side compressed
- Causes: infection, trauma, loss of blood due to blunt injury
- Secondary complications: mediastinal shift, compressions of superior and inferior vena cava
- Sx/signs: anxiety, depression, hypovolemic shock
What is a massive hemothorax?
1500cc blood loss into thoracic cavity
