Thorax and Lungs

Thorax and Lungs Study Notes

Anterior Thoracic Cage

  • Key structures and landmarks:

    • Clavicle: The bone that extends horizontally across the front of the thorax.

    • 2nd intercostal space: Located between the 2nd and 3rd ribs.

    • Costal cartilage: Flexible tissue that connects the ribs to the sternum.

    • Dome of the diaphragm: The upper part of the diaphragm which separates the thoracic cavity from the abdominal cavity.

    • Suprasternal notch: The notch located above the manubrium of the sternum.

    • Manubrium of the sternum: The broad upper part of the sternum.

    • Manubriosternal angle (angle of Louis): The angle formed between the manubrium and the body of the sternum, important anatomical landmark.

    • Costochondral junction: The point where the rib connects to the costal cartilage.

    • Body of sternum: The central part of the sternum.

    • Costal margin: The lower edge of the rib cage formed by the cartilages of the ribs.

    • Xiphoid process: The smallest and most inferior part of the sternum.

    • Costal angle: The angle formed by the costal margins.

Posterior Thoracic Cage

  • Key structures and landmarks:

    • C7 (Vertebra prominens): The seventh cervical vertebra, easily palpated in the neck.

    • T1 to T12: Thoracic vertebrae increments from T1 to T12.

    • Spinous process of T3: The bony prominence of the third thoracic vertebra.

    • Clavicle and Scapula: Skeletal structure surrounding the thoracic area, the scapula (shoulder blade) has an inferior angle that is relevant for physical assessment.

Reference Lines

Anterior Reference Lines

  • Midsternal line: Vertical reference line running down the center of the chest.

  • Midclavicular line: Line that runs vertically down from the midpoint of the clavicle.

  • Anterior axillary line: Line that runs down from the anterior axillary fold.

Posterior Reference Lines

  • Scapular line: Vertical line that runs through the inferior angle of the scapula.

  • Vertebral line: Straight line down the center of the spine.

Lateral Reference Lines

  • Anterior axillary line: As previously defined.

  • Posterior axillary line: Line running vertically at the posterior axillary fold.

  • Midaxillary line: Line located at the midpoint between the anterior and posterior axillary lines.

Mechanics of Respiration

  • Four Functions of the Respiratory System:

    1. Gas exchange: Oxygen uptake and carbon dioxide removal.

    2. Regulation of blood pH: Control of carbon dioxide levels to maintain acid-base balance.

    3. Protection against microorganisms: Filtering and warming inhaled air.

    4. Odor detection: Sensory function through olfactory receptors.

  • Changing Chest Size During Respiration:

    • Inspiration: Chest expands as muscles contract (diaphragm contracts, increasing vertical diameter; intercostal muscles elevate ribs, increasing A-P diameter).

    • Expiration: Chest contracts as muscles relax (internal intercostals depress ribs and diaphragm ascends).

    • Muscles involved in respiration:

    • Sternomastoid: Elevates sternum.

    • Scalenus muscles: Elevate upper ribs.

    • External intercostals: Elevate ribs.

    • Internal intercostals: Depress ribs.

    • Diaphragm: Descends as it contracts, increasing thoracic volume.

Subjective Data—Health History Questions

  • Key questions for evaluating respiratory health:

    • Cough.

    • Shortness of breath.

    • Chest pain with breathing.

    • History of respiratory infections.

    • Smoking history.

    • Environmental exposure.

    • Self-care behaviors.

Objective Data—The Physical Exam

Preparation

  • General preparations:

    • Position patient comfortably.

    • Make sure chest is properly exposed for examination.

    • Clean stethoscope endpiece with an alcohol swab before use.

Posterior Chest Examination

  1. Inspection:

    • Observe shape and configuration of the thoracic cage (A-P to transverse diameter).

    • Note skin color and condition.

  2. Palpation:

    • Assess symmetric expansion.

    • Check tactile (or vocal) fremitus using both hands.

    • Palpate the entire chest wall for any abnormalities.

  3. Auscultation:

    • Breath sounds:

      • Bronchial: Loud and harsh, best heard over the trachea.

      • Bronchovesicular: Medium pitch, heard over main bronchi.

      • Vesicular: Soft and low-pitched, heard over most lung fields.

    • Adventitious sounds:

      • Crackles: Intermittent sounds due to fluid in alveoli.

      • Wheeze: Continuous sounds due to narrowed airways.

      • Voice sounds:

      • Bronchophony: Elicited by asking the patient to say “99”; clearer sounds indicate lung consolidation.

      • Egophony: Listening for an “E” sound that sounds like an “A,” indicating lung pathology.

      • Whispered pectoriloquy: Enhanced whispering sounds indicating underlying lung disease.

Anterior Chest Examination

  1. Inspection:

    • Observe shape, configuration, skin color, and quality of respirations.

  2. Palpation:

    • Assess symmetric expansion and tactile fremitus.

  3. Auscultation:

    • Listen for breath sounds, differentiating normal from adventitious.

Charting Example

  • Subjective Data:

    • Patient reports no cough, shortness of breath, or chest pain.

    • No history of respiratory diseases; experiences “one or no” colds per year.

    • Has never smoked.

    • Last TB skin test negative, done four years ago.

  • Objective Data:

    • Inspection: A-P < transverse diameter; respirations noted at 16/min, relaxed and even.

    • Palpation: Symmetric chest expansion; tactile fremitus equal bilaterally; no tenderness, lumps, or lesions.

    • Percussion: Resonant over lung fields; diaphragmatic excursion = 5 cm bilaterally.

    • Auscultation: Clear vesicular breath sounds; no adventitious sounds.

Assessment

  • Intact thoracic structures.

  • Lung sounds are clear.

Abnormal Findings

Configurations of the Thorax

  • Types:

    1. Barrel chest

    2. Pectus excavatum

    3. Pectus carinatum

    4. Scoliosis

    5. Kyphosis

Abnormal Respiratory Patterns

  • Common patterns:

    • Sigh.

    • Tachypnea (rapid breathing).

    • Bradypnea (slow breathing).

    • Hyperventilation.

    • Hypoventilation.

    • Cheyne-Stokes respiration (periods of deep breathing followed by shallow breathing).

    • Biot's respiration (irregular breathing patterns).

    • Chronic obstructive breathing.

Adventitious Lung Sounds

  • Types:

    • Discontinuous sounds (e.g., crackles).

    • Continuous sounds (e.g., wheeze).

    • Pleural friction rub.

Common Respiratory Conditions

  • List of conditions:

    1. Atelectasis

    2. Lobar pneumonia

    3. Bronchitis

    4. Emphysema

    5. Asthma (reactive airway disease)

    6. Pleural effusion/thickening

    7. Congestive heart failure

    8. Pneumothorax

    9. Pneumocystis carinii pneumonia

    10. Tuberculosis

    11. Pulmonary embolism

    12. Acute respiratory distress syndrome (ARDS)

Clinical Questions

  • Tactile fremitus findings would be increased when:

    • The patient has a blocked bronchus.

    • The patient has a mild case of pneumonia.

    • The patient has an advanced case of pneumonia with consolidation.

    • The patient has a pleural effusion.

  • Which breath sound is present in the lower lobes of a patient who does not have any respiratory conditions?

    • Choices:

    • Vesicular

    • Bronchial

    • Bronchovesicular

    • Wheeze