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Tuberosity of distal phalanx of foot

The tuberosity of the distal phalanx of the foot is a roughened bony prominence located at the plantar aspect of the distal end of the distal phalanx of each toe. It serves as an important site for soft-tissue attachment and contributes to the structural support and weight-bearing function of the toes during gait and stance.

It is a key anatomical feature in foot anatomy, podiatry, trauma evaluation, and imaging of the forefoot.

Synonyms

  • Plantar tuberosity of the distal phalanx

  • Ungual tuberosity (toe)

Location

  • Situated at the distal end of each toe

  • Located on the plantar surface of the distal phalanx

  • Deep to the digital pulp (toe pad)

  • Distal to the shaft of the distal phalanx

  • Inferior to the nail bed and ungual process

Anatomical components

  • Osseous prominence of the distal phalanx

  • Cortical shell with cancellous core

  • Attachment site for:

    • Fibrous septa of the digital pulp

    • Terminal fibers of the flexor digitorum longus and brevis (indirectly via fibrous tissues)

  • Relationship to nail unit:

    • Supports the distal toe pad and nail complex

Relations

Superiorly:

  • Nail bed and ungual process

Inferiorly:

  • Plantar digital fat pad

Anteriorly:

  • Skin and subcutaneous tissue of the toe pulp

Posteriorly:

  • Shaft of the distal phalanx

Medially and laterally:

  • Collateral digital soft tissues

X-ray appearance

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

  • Tuberosity: Seen as a slight plantar bony prominence at the distal phalanx

  • Cortical outline: Smooth and continuous

  • Best visualized on: Lateral views of the toe

  • Relation to nail: Lies plantar to the ungual tuft

CT appearance

Non-contrast CT:

  • Tuberosity: Well-defined plantar bony projection of the distal phalanx

  • Cortical margins: Sharp and intact

  • Trabecular pattern: Normal cancellous bone

  • Spatial assessment: Excellent delineation of size, contour, and relation to nail unit

MRI appearance

T1-weighted images:

  • Cortical bone: Low signal intensity

  • Marrow of distal phalanx: High signal intensity

  • Tuberosity contour: Clearly outlined against surrounding soft tissues

T2-weighted images:

  • Cortex: Low signal

  • Adjacent soft tissues and pulp fat: High signal

  • Nail bed and pad: Well differentiated

STIR:

  • Fat suppression: Uniform suppression of marrow fat

  • Plantar soft tissues: Bright signal

  • Tuberosity margins: Well visualized

Proton density fat-saturated (PD FS):

  • Bone marrow: Suppressed fat signal

  • Digital pulp: High signal

  • Fibrous attachments: Low-signal bands extending from tuberosity

CT VRT 3D image

Tuberosity of Distal Phalanx of Foot 3D

MRI image

Tuberosity of Distal Phalanx of Foot mri anatomy labelled image-img-00000-00000

CT image

Tuberosity of Distal Phalanx of Foot CT