NORMAL NOSE

EMBRYOLOGY

• The nasal cavity originates from paired invaginations of ectoderm (nasal sacs). The nasal sacs are separated from the oral cavity by the oronasal membrane (which subsequently undergoes resorption).
• At 6wk GA - Nasal and oral cavities communicate freely through an opening that progressively closes by the developing palate.
• At 12 wk GA - Lateral palatine processes fuse medially with nasal septum. The oral and two nasal cavities are formed and separated.
• The external nose forms from the lower portion of the frontonasal prominence, which merge on both sides with the maxillary processes.
• Failure of development of frontonasal prominence results in complete or incomplete nasal aplasia.

ULTRASOUND

• Seen best on axial or sagittal views.
• Tip of nose, alae nasi, and columna are seen above the upper lip.

• Do not measure the soft tissues overlying the nasal bone.

• Nasal bone length (Table)– Guis et.al. 1995
• Nasal bone length (Graph)– Guis et.al. 1995

Video clip of Fetal Nasal Breathing Video clip of Nose / Lips / Nasal Fluid Flow