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Anterior tubercle of atlas

The anterior tubercle is a small bony prominence located on the anterior arch of the atlas (C1 vertebra). It lies midline on the anterior arch, just anterior to the odontoid process (dens) of the axis. The anterior tubercle serves as the attachment site for the longus colli muscles and anterior longitudinal ligament, contributing to cervical spine stability and flexion. It is palpable in imaging and surgical procedures and is a critical landmark in anterior cervical approaches.

The anterior tubercle is more prominent in some individuals and is usually small and rounded. Its anatomical integrity is important in trauma assessment, particularly atlas fractures, and in evaluating congenital anomalies or developmental variants of the cervical spine.

Function

  • Provides attachment for longus colli muscles

  • Serves as an insertion for the anterior longitudinal ligament

  • Contributes to stability of the atlantoaxial and atlanto-occipital joints

  • Supports cervical spine flexion and postural control

  • Acts as a surgical and imaging landmark

Synonyms

  • Anterior tubercle of C1

  • Anterior arch tubercle of atlas

  • Tuberculum anterius of atlas

MRI Appearance

T1-weighted images:

  • Appears as low signal intensity (hypointense) cortical bone

  • Surrounded by high signal bone marrow within the anterior arch

  • Fractures or abnormal lesions appear as altered signal or cortical discontinuity

T2-weighted images:

  • Cortical bone remains low signal (hypointense)

  • Bone marrow in the anterior arch is intermediate signal

  • Useful for detecting edema or fracture lines, which appear hyperintense

STIR (Short Tau Inversion Recovery):

  • Cortical tubercle remains low signal

  • Edema, inflammation, or acute fracture appears hyperintense, making it sensitive for trauma evaluation

T1 Post-Contrast (Gadolinium-enhanced):

  • Normal anterior tubercle shows no enhancement, except for thin periosteal vascularity

  • Pathological conditions (infection, tumor) show focal enhancement along affected cortical or marrow areas

CT Appearance:

  • Appears as a small hyperdense bony prominence on the anterior arch of C1

  • Axial and sagittal views clearly demonstrate cortical margins, fractures, or congenital anomalies

  • Essential for assessing trauma, surgical planning, and anatomical variations

MRI images

Anterior tubercle of atlas MRI AXIAL IMAGE

MRI images

Anterior tubercle of atlas