What Is The Respiratory System

Respiratory System


Ask history of present illness with special emphasis on onset (sudden, acute, subacute, or insidious), evolution of disease and response to therapy. The major symptoms of respiratory system disorder include fever, cough, coryza (viral URI or hay fever), sore throat and respiratory difficulty. Ask whether cough is mild or intractable, dry or associated with bubbling sounds in the throat or chest, diurnal or predominantly nocturnal. Infants and young children cannot expectorate sputum and they often swallow it and may bring out the phlegm in the vomitus or pass it in the stools. Spasmodic hacking cough is suggestive of bronchospasm, tracheitis, pertussis, cystic fibrosis, foreign body and aspiration. Cough is relatively an uncommon symptom in neonates and may occur due to aspiration and chlamydial infection. Inspiratory whoop following a bout of spasmodic cough is characteristic of pertussis but may occur in respiratory infections due to B. parapertussis, adenoviruses and chlamydiae. Cough with copious putrid expectoration is suggestive of bronchiectasis and pulmonary suppuration. There may be history suggestive of measles, pertussis and inhalation of foreign body at the onset.

Respiratory SystemIn children with recurrent respiratory infections, a detailed history should be taken to exclude inhalation of foreign body as evidenced by a sudden and dramatic episode of life threatening choking, cough and cyanosis. Ask for history of abnormal sounds during inspiration (stridor) and expiratory grunting in pneumonia and wheezing in bronchiolitis and bronchial asthma. Tachypnea and dyspnea are suggestive of acute lower respiratory infection, bronchospasm, atelectasis, and compression of lungs (pneumothorax, pleural effusion, mediastinal mass, diaphragmatic hernia). Retractions of chest are common and marked in children due to soft rib cage. Marked suprasternal retractions are seen in upper airway obstruction. The presence of cyanosis and feeding difficulty are suggestive of life threatening respiratory disorder requiring immediate hospitalization. History of recurrent episodes of cough with breathing difficulty are suggestive of bronchial asthma, bronchiectasis, foreign body, left-to-right shunt, cystic fibrosis, immunodeficiency state and gastro-esophageal reflux. Ask for history of dysphagia which may be acute (acute pharyngitis or tonsillitis, diphtheria, acute epiglottitis, retropharyngeal abscess etc.) or insidious (mediastinal mass, vascular ring) in onset. Hemoptysis is uncommon in children and may occur due to bronchiectasis, lung abscess, resolving lobar pneumonia, pulmonary hemosiderosis, pulmonary edema, mitral stenosis, tubercular cavity and bleeding disorder. Unlike hematemesis, hemoptysis is preceded by a bout of cough, the blood is bright red in color, and usually small in quantity. History of chest pain is uncommon and may occur due to pleurisy, pericarditis, pleurodynia, costochondritis, herpes zoster, trauma and coronary insufficiency (severe aortic stenosis or regurgitation). Family history of tuberculosis, bronchial asthma, and hay fever should be asked. Unsatisfactory living conditions, over crowding, environmental pollution, parental smoking and smoky chulla at home, are associated with increased incidence of respiratory infections and episodes of bronchospasm. The vaccination status of the child should be enquired. It provides useful guidelines to assess the respiratory disorder and make a correct diagnosis.

General Physical Examination

Assess whether the child is comfortable, tachypneic or dyspneic. While recording history, note whether accessory muscles of respiration and alae nasi are working or not. Inspiratory dyspnea occurs due to obstruction of upper airways while expiratory dyspnea is seen in children with obstructive lung disease. State of consciousness, build and nutrition, and putrid odor from the mouth should be noted. Audible sounds during breathing e.g. stridor, croup, hissing, grunting, stertorous, pharyngeal snores and wheezing may be heard. Grunting occurs when infant makes expiratory efforts through a partially closed glottis to increase end expiratory pressure to prevent collapse of alveoli during expiration. They are relatively common in children because of narrow air passages. Nature of cough whether intermittent, spasmodic, whoopy, metallic, bubbly etc. should be recorded. Note the character of voice or cry. The crying often facilitates auscultation of breath sounds in infants.

Temperature, pulse rate and its ratio to respiration (normal ratio being 4 to 1) should be noted. Respiration rate per minute, type of breathing, rhythm (normal, reversed, Cheyne-Stokes, Biot’s breathing), character (normal, inspiratory distress, expiratory distress), depth (normal, shallow, deep or Kussmaul’s breathing) and suprasternal, intercostal, subcostal recessions and movements of alae nasi should be looked for. Normal rhythm of breathing is characterized by inspiration – expiration – pause. Reversed rhythm i.e. expiratory grunt – inspiration – pause is seen in children with acute lower respiratory infection. Cheyne-Stokes breathing is characterized by temporary cessation of breathing (apnea) followed by respiratory efforts which gradually increase in magnitude to a maximum and then gradually diminish until apnea occurs once again. It occurs due to depression of respiratory center due to hypoxia, encephalitis or meningitis, increased intracranial pressure, uremia and congestive heart failure. Anemia, cyanosis, jaundice and lymphadenopathy should be looked for. E.N.T check up is essential to rule out upper respiratory tract infection, otitis media and sinusitis. The sphenoid sinuses are present at birth but ethmoid and maxillary sinuses are of clinical importance during early childhood. The frontal sinuses are usually not affected during first 10 years of age. Chronic sinusitis is associated with nasal obstruction with persistent mucopurulent nasal discharge, slight puffiness of eyelids and dark circles under the eyes. The important causes of chronic sinusitis include cleft palate, nasal allergy, Kartagener’s or Immotile cilia syndrome, Hurler’s syndrome, cystic fibrosis, choanal atresia and immunodeficiency disorders.

Look for clubbing of nails and osteo-arthropathy (clubbing with pain in the wrists and ankles), J.V.P. and position of trachea and apex beat.

Examination of Chest

The ready availability of roentgenographic examination and advances in imaging technology have rusted the art of clinical examination of chest. Anatomical areas for purposes of clinical examination of chest are as follows:

Front Supraclavicular, infraclavicular, mammary and inframammary areas.

Back Superior, middle and inferior axillary areas.

Back Suprascapular, interscapular, scapular, infrascapular and basal areas.

Surface Anatomy. The bifurcation of trachea coresponds to angle of Louis anteriorily and 4th thoracic spine posteriorily. A line drawn from 2nd thoracic spine to the 6th rib in the midclavicular line corresponds to the major interlobar fissure or upper border of lower lobe of the lung. The boundary between the upper and middle lobes is marked by a horizontal line drawn from sternum at the level of 4th costal cartilage to meet the major interlobar fissure line on the right side of chest. Mostly upper (middle also on the right side) and lower lobes are accessible to physical examination anteriorily and posteriorily respectively while all the lobes are accessible in the axillary area.

The surface anatomy of bronchopulmonary segments of lungs both infront.


The exposed chest should be inspected by standing at the head or foot side of the patient with eyes at the level of chest. The child, however, is best examined while sitting comfortably on a stool or standing with arms hanging limply by the sides.

Shape of chest. It is nearly circular or cylinderical in infants. The shape may be normal, barrel-shaped of emphysematous, pigeon chest or pectus carinatum (rickets, chondrodystrophy, spondyloepiphyseal dysplasia congenita. Noonan syndrome, Schwartz-Jampel syndrome, ashyxiating thoracic dystrophy, bronchial asthma), and funnel-shaped chest or pectus excavatum (Marfan syndrome, Noonan syndrome, mucosal neuroma syndrome). Harrison’s sulcus, kyphosis, levo or dextro scoliosis of spine should be looked for. Costochondral beading (rickety rosary) may be the sole evidence of early rickets. In every child with a chest deformity, the spinal deformity must be excluded.

Symmetry. Note whether chest is bilaterally symmetrical or not. Note the distance of medial borders of scapulae from midline on both the sides which is useful to assess any asymmetry of the chest. Drooping of one shoulder may occur in patients with fibrocaseous tuberculosis. Look for localized bulge (whether costal or intercostal bulge) or retraction (collapse or fibrosis). There is bulging of intercostal spaces in cases of pleural effusion or empyema. When empyema points through an intercostal space as a cystic swelling, it is reducible and cough impulse is present it is called empyema necessitans. The bony cage of chest may show localized bulge due to long standing cardiomegaly, intrathoracic mass lesion, deformities of ribs and spine.

Movements of chest. The breathing is mostly abdominal or abdominothoracic in infants. The range of movements, respiratory lag on a particular side and indrawing of suprasternal, intercostal and subcostal spaces should be looked for. Marked suprasternal recessions are suggestive of narrowing or obstruction of upper airways (laryngeal diphtheria, acute laryngotracheobronchitis, acute epiglottitis, laryngeal/tracheal foreign body, and angioneurotic edema).

The position of trachea and apex beat should be localized. The trachea is examined with child in supine position or sitting with slight flexion of neck. Place the index finger into the suprasternal notch, and gently push it backwards. Normally the finger should touch the trachea in midline. If trachea is deviated, the finger will slide into the tracheo-stemomastoid space. In a child with marked tracheal displacement, clavicular head of the stemomastoid muscle would be pushed forward as a visible bulge on the displaced side (Stenomastoid or Trail sign). Trachea may be pulled (towards the diseased side) due to collapse, fibrosis and thickened pleura. It may be pushed (towards the normal side) by pleural effusion, pneumothorax and a mass lesion.


The findings of inspection should be confirmed. Look for any tender areas, crepitus (subcutaneous emphysema, fracture of rib), assess any differences of movements on two sides of chest. Feel for any abnormal vibrations e.g. rhonchi. friction rub, coarse crackles and characteristic spongy feeling of subcutaneous emphysema. Vocal fremitus is looked for by comparing tactile transmission of spoken words or cry in infants, over identical areas on two sides of the chest. It may be normal and equal on two sides or decreased or increased over a particular area. It has the same significance as vocal resonance but is unreliable in children. Assess the expansion of chest on two sides.


The pleximeter finger (middle finger of the non dominant hand) should be placed in firm contact with the chest while rest of the fingers should be lifted off the chest. The pleximeter finger should be held parallel to the margin of the organ to be outlined. It should move from resonant towards the possible dull area. The tap should be ‘free’ and gentle and is best done with the middle finger (plexor) of the dominant hand. If organ or tissue to be percussed is superficial it is advised to do light percussion. For example direct (without pleximeter) light percussion over the clavicles is done to assess the apices of the lungs. The strokes should be of uniform force and executed by movements at the relaxed wrist. The plexor finger must be withdrawn immediately after the stroke. The intensity and quality of the sound produced and ‘feeling’ of resistance imparted to the pleximeter finger should be observed. The identical areas of chest on two sides should be compared simultaneously. The chest may be normally or equally resonant on two sides, there may be unilateral or bilateral hyperresonance, tympanitic note (large cavity, pneumothorax, diaphragmatic hernia), impaired resonance, dull or stony dull percussion note. Rising dullness (higher level of dullness in the axilla as compared to front and back) and shifting dullness should be looked for when pleural effusion is suspected.

“Auscultatory percussion”

It is more reliable and informative than the conventional percussion and can pick up small lesions upto 3 cm in diameter especially hilar or mediastinal lymphnodes, pulmonary infiltrates, atelectasis and patches of pneumonia. The patient sits up with arms resting on his thighs. The examiner stands or sits on either side of the patient. The examiner percusses over the manubrium sterni by tapping lightly with the distal phalanx of middle or index finger of dominant hand while listening with the diaphragm piece of stethoscope applied snugly by the other hand over the posterior chest wall. It must be ensured that percussion is applied with equal intensity over the same area of the manubrium while stethoscope explores both lung fields by comparing the intensity and quality of percussion note on corresponding anatomical areas from apex to base. In the end paravertebral areas are auscultated to detect possible mediastinal and hilar masses.


The infants and young children are best auscultated while mother or father supports the child against the security of her/his shoulders.

Character of Breath Sounds

Vesicular. The normal breath sounds produced in the alveoli are called vesicular. The inspiration is loud, high pitched and long, there is no pause after the inspiration, expiration is low in intensity and short in duration and is followed by a pause. In children, the normal breath sounds are peurile or harsh vesicular with slightly prolonged expiration (bronchovesicular).

Bronchial. The inspiration is low in intensity, and is followed by a pause while expiration is harsh, blowing, guttural, high pitched, loud and prolonged. The duration of inspiration and expiration is almost identical. The sounds have definite tubular quality. It may be normally heard over the neck and thoracic spine upto 4th thoracic vertebra (trachea). The bronchial breathing may be of the following types:

(a) High pitched or tubular (consolidation)
(b) Medium pitched (consolidation, small cavity or atelectasis with a patent bronchus).
(C) Low pitched or cavernous (large cavity)
(d) Amphoric (broncho-pleural fistula). It is low-pitched bronchial breathing with metallic overtones.

Intensity of Breath Sounds

It may be normal, decreased or absent on one or both sides. The abnormality may be localized to a particular lobe or affect the whole hemithorax.

Adventitious Sounds

Rhonchi. These are dry musical sounds produced due to narrowing, of air passages. The expiration is prolonged. They are monophonic in character when there is localized obstruction of a bronchus or polyphonic when there is generalized airway obstruction. They are classified on the basis of their pitch and site of origin.

(a) High pitched or sibilant rhonchi are produced in the bronchioles. They are audible during the end of inspiration or beginning of expiration and are better appreciated by placing the chest piece in front of infant’s mouth (acute bronchiolitis).

(b) Medium pitched rhonchi are produced in medium sized bronchi.

(c) Low pitched or sonorous rhonchi are produced in large bronchi. They are heard throughout both the phases of breathing and are often audible even without a stethoscope.

Crepitations or rales or crackles are bubbling or wet sounds produced by passage of air through the exudates collected in the alveoli, bronchioles, bronchi or trachea.

(a) Fine crepitations are produced by sudden opening of previously closed airways or alveoli and are audible during the end of inspiration (bronchopneumonia and congestive heart failure).

(b) Medium pitched crepitations (bronchitis and resolving pneumonia).

(c) Course bubbling crepitations are audible throughout both the phases of respiration and are loud in intensity (bronchiectasis).

The crepitations must be differentiated from pharyngeal sounds or sterterous breathing. The pharyngeal sounds disappear after suction and are better heard by auscultation over mouth and front of upper neck. In small infants, adventitious sounds from one side of the chest may be transmitted to the opposite side.

Pleural friction rub. It is unaltered by cough (c.f. crepitations), is more localized, and augmented by snug contact of chest piece of stethoscope to the chest wall. It is heard during the identical phases of inspiration and expiration and has a peculiar superficial leathery character. There may be localized chest pain. It disappears when two leaves of pleura are separated by further accumulation of exudates. At times pleural rub may be palpable with the palm.

Vocal Resonance

Both the intensity and quality of sound transmitted through chest piece of the stethoscope are looked for when child is asked to repeat some words (one, two, three) or made to cry. The intensity of vocal resonance may be equal and normal on two sides, absent or decreased (pleural effusion, pleural thickening, pneumothorax, emphysema, atelectasis) or increased (consolidation, cavity, infarction, atelactasis with patent bronchus). Bronchophony refers to increased vocal resonance when it is so loud that it appears that the sound is being produced in the ear pieces of stethoscope (consolidation, cavity). The audible vocal resonance, when child is just asked to whisper certain words is called as whispering pectoriloquoy and is indicative of markedly increased vocal resonance (broncho-pleural fistula). The nasal twang or bleating quality of vocal resonance is called aegophony and is audible at the upper level of pleural effusion due to partially collapsed underlying lung. It is produced by selective transmission of high frequency components of breath sounds.

Specific Signs

Hippocratic succussion or succussion splash. Whenever pleural effusion is suspected, splash should be elicited to rule out hydropneumothorax. The chest piece is affixed at the upper border of dullness and child is suddenly shaken to elicit splash of fluid.

Coin test (Bell tympany). A coin is placed in front of chest and tapped with another coin while chest piece is placed at an identical spot on the back. A loud bell-like tinkle is audible in patients with pneumothorax.

Friction test. The chest piece is placed on the center of the chest and friction is produced on either side of chest wall with a wooden spatula or finger nail. The conduction of the sound is distinctly better when chest is scratched on the side having pneumothorax.

Ewart’s sign. The bronchial breathing and bronchophony may be audible over the left lower interscapular area in a patient with pericardial effusion due to compression of left main bronchus leading to collapse.

d’Espine sign. The presence of bronchial breathing and increased vocal resonance in the midline over the back below the level of 4th thoracic vertebra in cases of mediastinal mass.

Mediastinal crunch (Hamman’s sign). In children with mediastinal emphysema, especially when associated with left sided pneumothorax, systolic crunching sounds may be heard on auscultation over left sternal border from third to fifth interspaces. Mediastinal air leaks may be associated with crepitus over the supraclavicular region without any subcutaneous emphysema of chest wall.

Diagnostic Features of Common Respiratory Disorders

Lobar pneumonia (consolidation). Sudden onset of fever, cough, chest pain, dyspnea and rusty sputum are characteristic symptoms. Trachea is central. The chest movements may be slightly impaired on the affected side, percussion note is dull, tubular bronchial breathing with crepitations, and increased vocal fremitus and vocal resonance are classical signs of consolidation.

Pleural effusion or empyema. There is history of chest pain, breathing difficulty, fever and cough. Onset may be sudden but is generally insidious. The patient prefers to lie on the affected side. Trachea and heart is displaced towards the opposite side. The chest may be bulging (especially intercostal spaces) on the affected side with reduced movements. There is stony dullness, rising dullness and sometimes shifting dullness on the affected side. Breath sounds are vesicular, diminished or absent without any adventitious sounds. Vocal fremitus and vocal resonance are reduced.

Atelectasis or collapse. History of inhalation of foreign body and recurrent chest infections should arouse the suspicion of atelectasis. Trachea and heart is pulled towards the side of atelectasis due to increased negative pleural pressure. Intercostal spaces may be narrowed on the affected side. Percussion note is impaired. Breath sounds are reduced in intensity, vesicular or distant bronchial if connecting bronchus is patent. Vocal fremitus and vocal resonance are reduced or increased depending upon the patency of connecting bronchus. The opposite lung may show compensatory emphysema.

Fibrosis. Thickened pleura, chronic infection with fibrosis, mucoviscidosis and idiopathic insterstitial fibrosis produce chronic respiratory insufficiency with dyspnea, cyanosis and clubbing. If unilateral or localized, chest is retracted and moves less on inspiration. Mediastinum is pulled towards the affected side. Percussion note is impaired. Breath sounds are vesicular and reduced in intensity. Crackles are commonly present. Associated consolidation or collapse may produce additional clinical findings. Evidences of chronic cor pulmonale may be seen in long standing cases.

Pneumothorax. Sudden chest pain, dyspnea and cyanosis herald the onset of pneumothorax. Subcutaneous emphysema may be evident over the neck and upper chest. Trachea and heart are pushed towards the opposite side. The affected side shows hyperinflation and reduced movements on breathing. Percussion note is hyperresonant. Breath sounds are vesicular and reduced in intensity, vocal fremitus and vocal resonance are reduced. When there is bronchopleural fistula, amphoric bronchial breathing with whispering pectoriloquoy is audible. Coin lest and friction tests may be positive.

Salient physical signs in common diseases of lungs
Signs Consolidation Collapse Fibrosis Pleural effusion Pneumothorax Emphysema
 Chest wall  Normal  No or minimal retraction  Significant chest wall retractions with impaired movements of chest  Bulging of intercostal spaces at the base with reduced chest movements  Diffuse asymmetric inflation of hemithorax with reduced chest movements on breathing  Barrel shaped symmetrical chest with poor expansion of chest
 Mediastinal shift  None  Same side  Same side  Opposite side  Opposite side  None
 Vocal fremitus  Increased  Normal or decreased  Decreased  Grossly diminished  Diminished  Diminished
 Percussion note  Dull  Impaired  Impaired  Stony dull with rising or shifting dullness  Tympanitic  Hyperresonant with loss of liver and cardiac dullness
 Breath sounds  Bronchial  Absent or bronchial*  Diminished or bronchial*  Diminished or absent, may be bronchial at upper border of effusion  Amphoric (if there is a broncho-pleural fistula) or diminished  Diminished with
 Bronchophony or whispering pectoriloquoy  Diminished or bronchophony  Diminished or bronchophony  Diminished or absent with aegophony at the upper border of effusion  Diminished or bronchophony  Diminished
 Fine crackles  None  Coarse crackles  Friction rub in early stages  Metallic crackles, succussion splash if there is – hydropneumothorax  Expiratory


Scheme for Presentation
 General physical examination  Comfortable, tachypneic or dyspneic, whether alae nasi and accessory muscles of respiration are working or not, audible sounds during breathing (grunt, stridor, croup, wheezing etc), state of nutrition, growth and development, and level of consciousness. Temperature, pulse, respiration (rate, type, character, depth, abnormal sounds recessions etc), and blood pressure. Anemia, cyanosis, jaundice, lymphadenopathy, detailed ENT checkup, clubbing, osteoarthropathy, position of trachea and apex beat, evidences of chronic cor pulmonale.
 Inspection  Describe findings in accordance with the standard format of clinical areas of chest on front, sides and back. Shape of chest on front, sides and back. Shape of chest, localized bulge (costal or intercostal spaces) or retractions, deformities (exclude spinal deformity), movements on breathing, expansion of chest, position of trachca (including stemomastoid sign) and apex beat.
 Palpation  Assess movements on two sides, tenderness, crepitus (subcutaneous emphysema), rhonchi, coarse crackles, friction rub and tactile fremitus on two sides.
 Percussion  Describe character (resonant, tympanitic) and intensity (hyper-resonant, normal, impaired, dull, stony dull) of percussion note over different sites on two sides, and shifting dullness on change of position.
 Auscultation  Describe character (vesicular, harsh vesicular, bronchial) and intensity (normal, increased, decreased, absent) of breath sounds, adventitious sounds and their character (crackles, rhonchi, pleural friction rub), vocal resonance (normal,decreased, increased, bronchophony, whispering pectoriloquoy and aegophony) and various diagnostic clinical signs whenever indicated such as Hippocratic succussion, coin test, friction test, Ewarts’ sign. d’Espine sign, Hamman’s sign etc.