Thorax & Spinal Configurations

Configurations of the Thorax

• Normal adult thorax has an elliptical shape. The anteroposterior-to-transverse diameter is documented as 1:2 or 0.70.
• Barrel chest has an equal anteroposterior-to-transverse diameter, and ribs are horizontal instead of having the normal downward slope. It i associated with aging, chronic emphysema, and asthma due to hyperinflation of the lungs.
• Pectus excavatum (funnel breast) is a sunken sternum and adjacent cartilages. The depression begins at the second intercostal space, more noticeable on inspiration. It is usually congenital and can be corrected surgically.
• Pectus carinatum is a forward protrusion of the sternum, with ribs sloping back at either side. Vertical depressions are present along costochondral junctions (pigeon breast).

Spinal Configurations

• Scoliosis is a lateral S-shaped curvature of the thoracic and lumbar spine, involving vertebrae rotation. It is more prevalent in adolescent age groups, especially girls, which may reduce lung volume, and potentially impair cardiopulmonary function.
• Kyphosis is an exaggerated posterior curvature of the thoracic spine (humpback) often associated with aging and osteoporosis, which can impair cardiopulmonary function.

Respiratory Patterns

• Normal adult respiratory rate is 10 to 20 breaths/min, with a depth of 500 to 800 ml. The ratio of pulse to respiration is 4:1.
• Sighs punctuate the normal breathing pattern to expand alveoli. Frequent sighs may indicate emotional dysfunction and can lead to hyperventilation and dizziness.
• Tachypnea is rapid, shallow breathing with a rate greater than 24 per minute, caused by respiratory insufficiency, pneumonia, alkalosis, pleurisy, and lesions in the pons.
• Hyperventilation involves an increase in both rate and depth, and can cause a decreased level of carbon dioxide in the blood. It can also compensate for conditions causing metabolic acidosis
• Bradypnea is slow breathing with a rate of less than 10 per minute, such as in drug-induced depression of the respiratory center in the medulla or diabetic coma.
• Hypoventilation is an irregular, shallow pattern. Can result from an overdose of narcotics or anesthetics, or from prolonged bed rest.
• Cheyne-Stokes respiration is a cycle in which respirations gradually wax and wane in a regular pattern, increasing in depth and then decreasing which may be caused by severe heart failure, drug overdose, and increased intracranial pressure.
• Biot respiration is similar to Cheyne-Stokes respiration, but the pattern is irregular. It is seen with head trauma, brain abscess, heat stroke, spinal meningitis, and encephalitis.
• Chronic Obstructive Breathing involves normal inspiration and prolonged expiration to overcome increased airway resistance. This can lead to dyspnea through air trapping because the person does not have enough time for full expiration.

Abnormal Tactile Fremitus

• Increased tactile fremitus occurs with conditions that increase the density of lung tissue, like compression or consolidation (pneumonia).
• Decreased tactile fremitus occurs when transmission of vibrations is obstructed by an obstructed bronchus, pleural effusion or thickening, pneumothorax, or emphysema.
• Rhonchal fremitus is vibration felt when inhaled air passes through thick secretions in the larger bronchi.
• Pleural friction fremitus is produced when inflammation of the pleura causes a decrease in lubricating fluid, detectable by palpation, synchronous with respiratory excursion.

Adventitious Lung Sounds

• Crackles (fine): Discontinuous, high-pitched crackling sounds, not cleared by coughing, heard during inspiration when inhaled air collides with previously deflated airways. Late inspiratory crackles occur with pneumonia or heart failure.
• Crackles (coarse): Loud, low-pitched bubbling sounds, present in early inspiration and expiration. They may decrease somewhat by suctioning or coughing. They occur when inhaled air collides with secretions in trachea and large bronchi.
• Atelectatic crackles: Sound like fine crackles that disappear after the first few breaths, usually in dependent lung. They occur when sections of alveoli are not fully aerated, they deflate and accumulate secretions.
• Pleural friction rub: A coarse, low-pitched grating sound and is inspiratory and expiratory that, which occurs when inflamed pleurae lose lubricating fluid.
• Wheeze (high-pitched, sibilant): High-pitched, musical squeaking sounds that predominate in expiration. They occur when air is squeezed through passageways narrowed by collapsing, swelling, secretions, or tumors.
• Wheeze (low-pitched, sonorous rhonchi): Low-pitched, monophonic musical snoring sounds that are more prominent on expiration, and may clear somewhat by coughing. They indicate airflow obstruction.
• Stridor: High-pitched, monophonic, inspiratory, crowing sound louder in the neck. It occurs in larynx or trachea due to upper airway obstruction from swollen, inflamed tissues or a lodged foreign body.