Module 6: Respiratory

Thoracic cage

Conical bony structure defined by sternum

12 pairs of ribs

12 thoracic vertebrae

Suprasternal notch

U-shaped depression above the sternum between the clavicles

Sternal angle (Angle of Louis)

Articulation of manubrium and body of sternum continuous with second rib

site of tracheal bifurcation into R/L main bronchi

upper border of atria of <3

Costal angle

R/L costal margins form an angle where they meet at xiphoid process

90 degree or less unless PT has emphysema (and lungs overinflated)

Vertebra prominens

Most prominent C7 spinous process felt when neck is flexed forward

Anterior reference lines

Midsternal

Midclavicular

Anterior axillary - end of clavicle

Posterior reference lines

Vertebral

Scapular lines

Lateral reference lines

Anterior, mid, and posterior axillary lines

Lung lobes (lateral)

Lung tissue extends from apex in axilla down to 7th or 8th rib

Lobes of the lung: landmarks

Left lung has no middle lobe (<3)

Anterior chest contains mostly upper and middle lobe, posterior contains almost all lower lobes

Visceral pleura

Serous membrane lining lung surfaces dipping into fissures

contineous w parietal pleura lining

Pleural cavity

Potential space with negative pressure and lubricating fluid between pleural layers

Holds lungs tightly against chest wall

Costodiaphragmatic recess

Pleural extension 3 cm below lung margin that can fill and compromise expansion

Parenchyma

functional tissue of an organ as distinguished from connective and supporting tissue

Right main bronchus

Shorter, wider, more vertical branch of trachea prone to aspiration

Dead space

Conducting airways not used for gas exchange (~150 mL in adult)

Goblet cells

Mucus-secreting airway cells that trap inhaled particles

Cilia

Hair-like structures sweeping mucus toward the pharynx

Acinus

Functional unit of lung—bronchioles, alveolar ducts, sacs, and alveoli for gas exchange

Respiratory functions

Supply O₂, remove CO₂, maintain acid-base balance (homeostasis), maintaining heat exchange

Ventilation control

Primarily driven by ↑CO₂ (hypercapnia), secondarily by ↓O₂ (hypoxemia) in blood

Humoral regulation

Normal stimulus to breathe

inc of CO2 in blood (hypercapnia)

Less effectively: dec in o2 in blood (hypoxemia)

Ventilation vs respiration

Ventilation: physical act of breathing

Respiration: cellular air exchange

ETS vulnerability: infants and children

Environmental tobacco smoke (ETS)

Tobacco smoke exposure increases SIDS, respiratory illness, and adolescent smoking

Pregnant respiratory change

Enlarging uterus elevates diaphragm, increases tidal volume, and causes dyspnea

Aging adult respiratory change

Dec vital capacity

Inc residual volume

Lead to dec gas exchange

Lung cancer genetics

Second most diagnosed US cancer and leading cancer death in the US

linked to smoking-induced mutational burden

Tuberculosis burden

Airborne infection affecting 1/3 of global population (social and migratory disease)

requiring detection and treatment

Asthma prevalence

Most common chronic childhood disease influenced by genetic and environmental factors

Highest burden in low SES

extrinsic/allergic asthama

long-term exposure to traffic-related air pollution (TRAP)

Apgar respiratory score

1-minute score for: respiratory effort, muscle tone, reflex irritability, color

0-2 = severe depression

3-6 = moderate depression requiring support

Infants: breathing considerations

Obligate nose breathing until 3 months

Count full minute

30-40 breaths/min (normal is 12-20 for adults), spikes to 60 when feeding or temp changes

Brief apnea common in premature infants

Pregnant women: dev competence

Thoracic cage may be wider

Inc in 40% todal vol

Kyphosis: inc AP diameter

Poster chest palpation

Thumbs should move apart 3-5 cm

confirm symmetric chest expansion

Tactile fremitus

Palpable vibration when patient repeats "99," best between scapulae and sternum

Dec: obstructed bronchus, pneumothorax, pleural effusion, or emphysema

Inc: compression/consolidation of lung tissue, bronchus is patent

Percussion resonance

Low-pitched, clear, hollow sound over healthy lung tissue

Bronchial breath sounds

Loud, high-pitched over trachea and larynx

expiration > inspiration

harsh, hollow tubular sound

Bronchovesicular sounds

Moderate-pitched over major bronchi (fewer alveoli)

inspiration = expiration

mixed sound

Vesicular breath sounds

Soft, low-pitched in peripheral fields

inspiration > expiration

rustling sound

Adventitious sounds

Added sound not normal for lungs

- crackles/rales

- wheeze/rhonchi

Atelectatic crackles

Short, popping, crackling sounds that sound like fine crackles but do not last beyond a few breaths

Adventitious sound that is not pathologic

Anterior palpation

Check symmetric chest expansion, tactile fremitus, tenderness, lumps, and skin turgor

Anterior percussion

Percuss apices, avoid breast tissue

identify cardiac and liver dullness located in 5th intercoastal space in right midclavicular line

gastric tympany on left

Anterior auscultation

Listen from apices to 6th rib in sequence

listen to one full inspiration and full expiration

displacing breast tissue as needed

Lateral auscultation

Right has 3 auscultatory points including the side boob due to 3 lobes

Pulse oximetry

Noninvasive SpO₂ measurement with normal 97-98% in healthy adults

Barrel chest

Equal AP to transverse diameter and horizontal ribs

normal in aging or bc of hyperinflation

Makes it hard to get air out o lungs

Scoliosis

Lateral S-shaped spine curvature that can impair lung volume if > 45°

Kyphosis

Exaggerated posterior thoracic curvature causing back pain and potential respiratory compromise

Neck may hyperextend to compensate level of vision

Pectus excavatum

Funnel breast

Sunken sternum and adjacent cartilages

most notable at inspiration

congenital

may compress the <3

Pectus carinatum

Pigeon breast

Forward protrusion of sternum that can restrict chest expansion and cardiopulmonary function

Severe cases can compress the <3

Tachypnea

Rapid breathing rate above normal age-specific range

Bradypnea

Slow breathing rate below normal age-specific range

Cheyne-Stokes respiration

Cyclic breathing with alternating hyperpnea and apnea indicating severe disease

COPD breathing

Prolonged expiration, accessory muscle use, and decreased breath sounds in chronic obstruction

air trapping

Discontinuous sounds

Crackles—fine

Crackles—course

Atelectatic crackles

Pleural friction rub

Continuous sounds

Wheeze—sibilant

Wheeze—sonorous rhonchi

Stridor

Diagnostic clues: pulmonary

alveolar

interstitial obstruction of airflow

Diagnostic clues: cardiac

arrhythmia

heart failure

restrictive or constrictive pericardial disease

Diagnostic clues: gastroinstinal

aspiration

Diagnostic clues: neuromuscular

respiratory muscle weakness

Diagnostic clues: psychological

anxiety