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Topic

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Major alar cartilage

The major alar cartilage (lower lateral nasal cartilage) is a paired, curved hyaline cartilage forming the structural framework of the nasal tip and nostrils. It plays a crucial role in defining nasal tip shape, nostril contour, and external nasal valve support.

This cartilage is a key anatomical structure in facial anatomy, rhinoplasty, trauma evaluation, and imaging of the external nose.

Synonyms

  • Lower lateral nasal cartilage

  • Greater alar cartilage

Location

  • Located in the lower third of the external nose

  • Inferior to the lateral (upper lateral) nasal cartilages

  • Lateral to the septal cartilage

  • Forms the margins of the nostrils

  • Deep to the nasal skin and superficial musculoaponeurotic system

Anatomical components

  • Paired hyaline cartilages, each composed of:

    • Medial crus:

      • Forms the columella

    • Intermediate (dome) segment:

      • Defines the nasal tip

    • Lateral crus:

      • Forms the alar rim and nostril margin

  • Flexible configuration allowing nasal tip mobility

Relations

Superficially:

  • Nasal skin and subcutaneous tissue

  • Nasal muscles (nasalis, dilator naris, depressor septi nasi)

Deep:

  • Nasal vestibular mucosa

Medially:

  • Columella

  • Septal cartilage (via medial crura)

Laterally:

  • Fibrofatty tissue of the alar lobule

Superiorly:

  • Lateral (upper lateral) nasal cartilages

Inferiorly:

  • Nasal vestibule and nostril opening

Developmental anatomy

  • Derived from nasal cartilage primordia

  • Fully formed at birth

  • Remains flexible throughout life

  • Does not ossify, unlike nasal bones

X-ray appearance

Plain radiographs:

  • Major alar cartilage: Not directly visualized

  • Assessment: Indirect evaluation through nasal soft-tissue contour

  • Nasal bones: Seen separately as radiopaque structures

CT appearance

Non-contrast CT:

  • Cartilage: Soft-tissue density structure at the nasal tip and alar margins

  • Configuration: Curved, symmetric appearance

  • Relationship: Clearly separated from nasal bones and septal cartilage

Post-contrast CT:

  • Cartilage: No enhancement

  • Surrounding soft tissues: Mild enhancement of skin and mucosa

MRI appearance

T1-weighted images:

  • Major alar cartilage: Low-to-intermediate signal intensity

  • Surrounding fat: High signal providing contrast

T2-weighted images:

  • Cartilage: Intermediate signal intensity

  • Vestibular mucosa and soft tissues: Relatively higher signal

Post-contrast T1-weighted images:

  • Cartilage: No enhancement

MRI images

Major alar cartilage MRI AXIAL

MRI images

Major alar cartilage MRI