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Tuberosity of first metatarsal bone

The tuberosity of the first metatarsal bone is a prominent bony projection located at the base of the first metatarsal on the medial aspect of the foot. It serves as an important site for ligamentous and muscular attachment and plays a role in maintaining the medial longitudinal arch and stability of the first ray.

It is a key landmark in foot anatomy, biomechanics, trauma assessment, and imaging of forefoot structures.

Synonyms

  • First metatarsal tuberosity

  • Medial tubercle of the first metatarsal

Location

  • Situated at the proximal end of the first metatarsal bone

  • Located on the medial aspect of the foot

  • Anterior to the medial cuneiform

  • Posteromedial to the shaft of the first metatarsal

  • Superficial and subcutaneous along the medial border of the foot

Anatomical components

  • Osseous prominence of the first metatarsal base

  • Cortical shell with cancellous core

  • Attachment sites for soft tissues:

    • Tibialis anterior tendon (partial insertion)

    • Peroneus longus tendon (via plantar groove and base region)

    • Capsuloligamentous structures of the first tarsometatarsal joint

Relations

Anteriorly:

  • Shaft of the first metatarsal

Posteriorly:

  • Medial cuneiform

Medially:

  • Subcutaneous tissue and skin

Laterally:

  • First metatarsal base and tarsometatarsal joint

Inferiorly (plantar):

  • Plantar ligaments and peroneus longus tendon groove (nearby)

Superiorly (dorsal):

  • Dorsal ligaments and extensor tendons (in proximity)

X-ray appearance

Plain radiographs (AP, oblique, and lateral foot views):

  • Tuberosity: Seen as a medial bony prominence at the base of the first metatarsal

  • Cortical margins: Smooth and well-defined

  • Relationship: Forms part of the medial contour of the foot

  • Best visualized on: AP and oblique views

CT appearance

Non-contrast CT:

  • Tuberosity: Well-defined osseous projection at the base of the first metatarsal

  • Cortical outline: Sharp and continuous

  • Trabecular pattern: Normal cancellous bone texture

  • Spatial evaluation: Precise assessment of shape, orientation, and surface contour

  • Articulation: Clear depiction of its relationship with the medial cuneiform

MRI appearance

T1-weighted images:

  • Cortical bone: Low signal intensity

  • Marrow within tuberosity: High signal intensity

  • Contour: Clearly delineated against surrounding soft tissues

T2-weighted images:

  • Cortex: Low signal

  • Adjacent joint fluid or soft tissues: High signal

  • Tendon insertions: Low-to-intermediate signal bands

STIR:

  • Fat suppression: Uniform suppression of marrow fat

  • Tuberosity margins: Well visualized

  • Surrounding soft tissues: High signal contrast

Proton density fat-saturated (PD FS):

  • Bone marrow: Suppressed fat signal

  • Tendon and ligament attachments: Well delineated as low-signal structures

  • Joint and peritendinous regions: High signal

CT VRT 3D image

Tuberosity of first metatarsal bone 3d

MRI image

Tuberosity of first metatarsal bone mri anatomy labelled image-img-00000-00000

X Ray image

Tuberosity of first metatarsal bone