Thorax Anatomy and Physiology

• The purpose of the thorax exam is to assess its health and function.
• This includes assessing the ribcage, muscles, heart, and lungs.
• The thorax is between the neck and the abdomen.
• It facilitates respiration and protects vital organs.
• The thorax contains organs/tissues active in the respiratory, cardiovascular, nervous, immune, and digestive systems.
• Respiratory system components include the lungs, bronchi, trachea, and pleura.
• Cardiovascular system components include the heart, pericardium, and great vessels.
• Thorax nervous system components include: vagus nerve, sympathetic chain, phrenic nerve, and recurrent laryngeal nerve.
• The immune system component of the thorax is the thymus.
• The digestive system component of the thorax is the esophagus.

Physiology of Thorax

• The thorax is a bony cage formed by the sternum (breastbone), ribs, and thoracic vertebrae of the spine.
• It houses the organs of the respiratory and cardiovascular systems.
• It also plays an important role in respiration.
• The diaphragm, a dome-shaped muscle at the bottom of the thoracic cavity, is the main breathing muscle.
• The lungs are the main respiratory organs within the thoracic cavity.
• Bronchi and bronchioles in the lungs facilitate the exchange of O2 and CO2.
• The pleura, a double-layered membrane, surrounds each lung, reduces friction, and aids lung expansion/contraction.
• The thorax contains the heart, a vital circulatory organ.
• The heart pumps oxygenated blood to tissues and receives deoxygenated blood for lung oxygenation.
• The heart is in the mediastinum, the thoracic cavity's central compartment.
• Accessory muscles of inspiration are the sternocleidomastoid and scalenus.
• Major muscles of inspiration are the external intercostal muscles and diaphragm.
• Internal intercostal muscles and abdominal muscles are muscles of active expiration.

Preparing for a Thorax Examination

• Hand hygiene and patient privacy are important.
• Use appropriate lighting with proper patient positioning.
• Greet the patient and explain assessment techniques.
• A warm, comfortable, and well-lit room is important.
• Patients should remove clothes from the waist up and wear an examination gown.
• Place the patient in an upright sitting position.
• If patient cannot tolerate sitting position, position supine, bedridden patient from side to side.
• Expose the area being assessed and drape women to cover their breasts when the posterior thorax is assessed.
• Proceed from lung apices to bases, right to left to lateral.
• Needed equipment for the examination includes: stethoscope, watch with second hand and tape measure/marker.

Inspection

• Inspect the client's sitting position to observe the use of accessory muscles to breath.
• The client will be sitting up and relaxed breathing easily with no use of accessory muscles in a normal, healthy patient.
• Shoulder muscle use facilitates inspiration in cases of airway obstruction, making it an abnormal finding.
• Tripod positions should be avoided.
• Inspect for nasal flaring, inspect the color and the shape of the nails.
• Under normal conditions there would be an absence of nasal flaring.
• Client may have normal and even color of the skin.
• Nasal flaring occurs during labored respirations.
• Clubbing nails indicates chronic hypoxia.
• Inspect the chest for shape and symmetry as well as muscle development.
• Estimate anteroposterior diameter for shape and inspect right and left.
• The thorax should be symmetrical, with normal and equal muscle development.
• Scapulae bilaterally symmetry is expected.
• Skeletal deformities, like scoliosis and kyphosis, may limit chest expansion.
• Scoliosis, kyphosis, pectus carinatum, and pectus excavatum are abnormal findings.
• Inspect presence of superficial veins.
• Observe respiration for rate and quality.
• Normally-dilated superficial veins are not seen.
• Expected respiration rate is 12-20 breaths/minute.
• Abnormal respiration findings include: bradypnea, <12 breaths per minute, tachypnoea, >20 breaths per minute, Kussumaul breathing (deep and laborious), and irregular breathing pattern.

Palpation

• Use fingers to palpate for tenderness, sensation, warmth, masses, and pulsations.
• Patient should have normal boy temperature and no tenderness, masses, or abnormal pulsations.
• Abnormal findings include presence of tenderness, abnormal body temperature/pulsations, and masses or abnormalities
• Assess chest expansion.
• Ask the client to take a deep breath and observe for movement of thumb.
• For anterior thorax assessment, place hands around chest (under nipples) with thumb in the middle
• For posterior thorax assessment, place hands at the level of T9 or T10.
• Both thumbs should move apart symmetrically with each breath.
• Unilateral or unequal movement of thumbs indicates chest wall injury or pain.
• Palpate for crepitus, a crackling sound sensation indicating subcutaneous emphysema.
• Palpate for fremitus.
• Move hand at each area and ask client to say "ninety-nine" to assess all areas for symmetry and vibrations.
• Use fingers to follow the sequence.
• Fremitus is the vibration felt on the patient's chest.
• There should be normal sensations and no crackles.
• Vibrations should be felt with both hands as the client says "ninety-nine".
• An abnormal finding is the presence of crackles along with abnormal sensations.
• Increased fremitus can occur due to poor ventilation.
• Decreased fremitus can occur due to pleural effusion, pulmonary edema, or pneumonia.

Percussion

• Percussion tones are determined by tapping a surface to determine underlying structure.
• Resonance is the percussion tone over normal lung tissue.
• Hyperresonance is heard in cases of trapped air, such as emphysema or pneumothorax.
• Dullness is present when fluids replace air in the lung or pleural space.

Auscultation

• Start auscultation at the apex of the right lung and listen for an entire respiratory cycle.
• Repeat on the left apex.
• Move down about every five centimeters or every other intercostal space comparing both sides.
• Auscultate on the anterior thorax, posterior thorax, and lateral aspects.
• Expected finding during auscultation is normal breathy sounds.
• Adventitious (abnormal) sounds during auscultation can indicate decreased sounds (like in emphysema); absent sounds (like in tumors, empyema or hemothorax); crackles, wheezes, stridor, and/or pleural friction rub.

Heart related Thorax Exam

• Inspect for visible pulsations.
• Observe jugular veins for visible pulsations.
• No pulsations should be visible, except in the mitral area.
• Jugular vein should not be distended, bulging, or protruding.
• Distension and bulging may indicated right sided heart failure.
• Palpate the apical pulse using the palmar of hand/index finger over the mitral area.
• Palpate for abnormal pulsation using the palmer surface to palpate the apex, left sternal border, and base.
• Apical impulse should be palpable at the mitral area.
• There should be no pulsation felt on other sites.
• Absence of apical pulse palpation can indicate Pulmonary emphysema.
• A thrill indicates murmurs.
• Percussion is used to note the enlargement of the dullness (thudlike sounds) of the cardiac region.
• There should be a noticeable left border apex and right border right sternal margin.
• Absent sounds can mean issues like Pericardial effusion.
• Auscultate valve areas: aortic, pulmonic, tricuspid, and mitral areas of the heart.
• Listen for heart sounds S1 and S2 which are described as lub-dub sounds.
• Abnormal murmurs or pericardial friction rubs can indicate abnormalities.

Documenting Findings

• Document: thorax examination, inspection, respiratory assessment, auscultation of the lungs, cardiovascular assessment, and percussion. The thorax appearance should be symmetrical with no visible deformities.
• The skin over the thorax should be intact with normal color and texture.
• No lesions, masses, any abnormalities noted.
• The patient's respiratory rate should be within the normal range with an indication of breaths per min.
• Breathing should be regular and unlabored.
• Chest expansion during inhalation should be equal bilaterally.
• No signs of accessory muscle use or retractions should present.
• Normal vesicular breath sounds can be heard bilaterally in lung fields.
• No adventitious breath sounds will be detected.
• Heart sounds will be heard and be regular, with no murmurs/abnormal heart sounds.
• The point of maximal impulse is palpated at the fifth intercostal space, midclavicular line, normal size/location.
• Percussion reveals resonant sounds over lung fields that indicates normal air-filled space.
• No signs of dullness or hyperresonance will be noted.
• Thorax examination must show normal findings with no apparent respiratory, cardiovascular, or chest wall abnormalities.
• There should be no further diagnostic testing or interventions needed.
• A follow-up to monitor regular healthcare plans should be scheduled.

Common Referral Criteria

• Abnormal breath sounds, cardiac murmurs, and dullness on percussion.
• Other reasons to refer is due to: abnormal heart sounds, suspicion of lung masses or tumors, suspected cardiopulmonary diseases, persistent unexplained symptoms and High-Risk Populations.