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FETAL LUNGS |
EMBRYOLOGY |
ULTRASOUND |
- First Trimester.
Difficult to differentiate from liver because: - Similar echogenicity.
- Diaphragm not yet evident.
- Second Trimester.
- Can be seen in early second trimester.
- Homogeneous mid-range echoes, although echogenicity can vary without being pathological.
- Third Trimester. Lung becomes more echogenic than liver in late second and third trimester. Muscular wall of diaphragm more visible.
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Video clip of Fetal Nasal Breathing
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- Discrete pulmonary nodules not evident unless pleural fluid extends into fissures marking the lobar boundaries.
- The lungs heart and thoracic cage grow at a constant rate so that the ratio between the heart and thoracic circumference is constant in the second and third trimester.
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13 weeks of gestation |
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20 weeks of gestation |
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32 weeks of gestation |
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Term – 38 weeks of gestation |
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- Position and axis of the heart provides useful information when evaluating the normal thoracic cavity.
NORMAL MEASUREMENTS |
- Thoracic
length (Table) – Chitkara et.al. 1987
- Thoracic length (Graph) – Chitkara et.al. 1987
- Thoracic length (Table) (Graph)
