A respiratory examination, or lung examination, is performed as part of a physical examination, in response to respiratory symptoms such as shortness of breath, cough, or chest pain, and is often carried out with a cardiac examination. The four steps of the respiratory exam are inspection, palpation, percussion, and auscultation of respiratory sounds, normally first carried out from the back of the chest. Stages After positioning in which the patient sits upright with their arms at the side, with the chest clear of clothing, the four stages of the examination can be carried out. In order to listen to the lungs from the back the patient is asked to move their arms forward to prevent the scapulae (shoulder blades) from obstructing the upper lung fields. These fields are intended to correlate with the lung lobes and are thus tested on the anterior (front) and posterior (back) chest walls. Inspection The examiner then estimates the patient's respiratory rate by observing how many times the patient breathes in and out within the span of one minute. This is typically conducted under the pretext of some other exam, so that the patient does not subconsciously change their baseline respiratory rate, as they might do if they were aware of the examiner observing their breathing. Adults normally breathe about 14 to 20 times per minute, while infants may breathe up to 44 times per minute. After obtaining the patient's respiratory rate, the examiner looks for any signs of respiratory distress, which may include: Cyanosis, a bluish tinge of the extremities (peripheral cyanosis), or of tongue (central cyanosis) Pursed-lip breathing Accessory muscle use, including the scalene and intercostal muscles Diaphragmatic breathing, paradoxical movement of the diaphragm outwards during inspiration Intercostal indrawing Decreased chest–chest movement on the affected side An increased jugular venous pressure, indicating possible right heart failure The anterior and posterior chest wall are also inspected for any abnormalities, which may include: Kyphosis, abnormal anterior-posterior curvature of the spine Scoliosis, abnormal lateral curvature of the spine Barrel chest, bulging out of the chest wall; normal in children; typical of hyperinflation seen in chronic obstructive pulmonary disease (COPD) Pectus excavatum, sternum sunken into the chest Pectus carinatum, sternum protruding from the chest In addition to measuring the patient's respiratory rate, the examiner will observe the patient's breathing pattern: A patient with metabolic acidosis will often demonstrate a rapid breathing pattern, known as Kussmaul breathing. Rapid