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Anterior nasal spine

The anterior nasal spine (ANS) is a midline bony projection at the lower margin of the nasal aperture, formed by the fusion of the two maxillary bones. It serves as the anterior support for the cartilaginous nasal septum and forms the inferior boundary of the piriform aperture, contributing to the overall shape and symmetry of the nasal skeleton. The ANS is triangular in shape, typically pointed anteriorly, and can vary in size and prominence between individuals. It is covered by periosteum and soft tissue, and its position provides a stable attachment point for the columellar base and nasal septal cartilage. The ANS also acts as a reliable skeletal landmark in craniofacial measurements and cephalometric analysis.

Synonyms

  • Nasal spine of maxilla

  • Midline nasal spine

  • ANS

Function

  • Provides attachment for the cartilaginous nasal septum

  • Supports the lower nose and nasal tip

  • Serves as an important anatomical landmark for craniofacial measurements

  • Maintains midline symmetry of the nasal skeleton

MRI Appearance
T1-weighted images:

  • Appears as a small, linear hypointense structure within surrounding soft tissue

  • Surrounded by hyperintense subcutaneous fat, which provides natural contrast

  • Fractures or bone lesions may appear as disruption of the normal low-signal continuity

T2-weighted images:

  • ANS is hypointense, with surrounding fat and soft tissues appearing hyperintense

  • Useful for identifying bone marrow edema or inflammatory changes

STIR (Short Tau Inversion Recovery):

  • Fat suppression enhances visualization of bone marrow and soft tissue pathology

  • Normal ANS remains hypointense, while fractures or inflammation appear hyperintense

CT Appearance

  • ANS appears as a hyperdense, well-corticated bony projection at the base of the nasal aperture

  • Surrounding air of the nasal cavity appears hypodense, providing natural contrast

  • Easily visualized in axial, coronal, and sagittal planes for fracture assessment, congenital anomalies, or surgical planning

  • Cortical continuity and shape can be clearly evaluated for variations in prominence or angulation

MRI images

Anterior nasal spine mri axial image -img-00000-00000