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Body of first metatarsal bone

The body of the first metatarsal bone refers to the elongated shaft between its proximal base and distal head. It is the shortest and thickest metatarsal, designed to bear significant load during gait and push-off. Its robust structure and alignment are essential for normal biomechanics of the forefoot and medial longitudinal arch.

It is a key structure in foot anatomy, orthopedic evaluation, sports medicine, and foot imaging.

Synonyms

  • Shaft of the first metatarsal

  • Diaphysis of the first metatarsal

Location

  • Situated in the medial forefoot

  • Between the base and head of the first metatarsal

  • Lies medial to the second metatarsal

  • Extends from the medial cuneiform proximally toward the hallux distally

  • Forms part of the medial column of the foot

Anatomical components

  • Cylindrical diaphysis with thick cortical bone

  • Central medullary canal

  • Dorsal surface:

    • Smooth and subcutaneous

  • Plantar surface:

    • Grooved for tendon and ligament attachments

  • Medial and lateral surfaces:

    • Provide attachment for interosseous and capsular structures

Relations

Superiorly (Dorsally):

  • Extensor hallucis longus tendon

  • Extensor hallucis brevis tendon

Inferiorly (Plantar):

  • Flexor hallucis longus tendon (distal course)

  • Plantar fascia and intrinsic foot muscles

Medially:

  • Abductor hallucis muscle

Laterally:

  • First dorsal interosseous muscle

  • Second metatarsal bone

Proximally:

  • Base of first metatarsal and medial cuneiform

Distally:

  • Head of the first metatarsal and first metatarsophalangeal joint

X-ray appearance

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

  • Body: Thick, straight shaft with dense cortical margins

  • Medullary canal: Visible central lucency

  • Alignment: Parallel with adjacent metatarsals

  • Articular ends: Clearly defined proximally and distally

CT appearance

Non-contrast CT:

  • Body: Dense cortical shell with central medullary cavity

  • Cortical thickness: Greater than other metatarsals

  • Trabecular pattern: Uniform cancellous bone

  • Orientation: Clearly demonstrates shaft curvature and rotational alignment

MRI appearance

T1-weighted images:

  • Cortical bone: Low signal intensity

  • Marrow: High signal intensity within the shaft

  • Periosteum: Thin low-signal outline

T2-weighted images:

  • Cortex: Low signal

  • Marrow: Intermediate signal

  • Adjacent soft tissues: Higher signal than bone

STIR:

  • Fat suppression: Uniform suppression of marrow fat

  • Shaft margins: Well delineated

  • Surrounding muscles and tendons: High contrast against suppressed marrow

Proton density fat-saturated (PD FS):

  • Marrow fat: Suppressed

  • Cortex: Low signal

  • Soft tissue interfaces: Clearly visualized

MRI image

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

CT VRT 3D image

Body of first metatarsal bone