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Body of metatarsal bone

The body of the metatarsal bone (also known as the shaft) forms the elongated central portion between the base and head. It is prismoid and slightly concave on its plantar surface, designed to bear weight, absorb impact, and transmit forces during gait. The dorsal surface is gently convex, and the bone tapers distally toward the head.

Each metatarsal (I–V) consists of a base (proximal end) articulating with tarsal bones and adjacent metatarsals, a shaft (body) forming the main lever arm of the foot, and a head (distal end) that articulates with the proximal phalanx of the corresponding toe. The body provides attachment for interosseous muscles, ligaments, and tendons critical for stability and propulsion.

Synonyms

  • Shaft of metatarsal

  • Diaphysis of metatarsal bone

Location and Structure

  • Lies between the base (proximally) and head (distally) of each metatarsal.

  • Shape: Slightly curved, with dorsal convexity and plantar concavity.

  • Surfaces:

    • Dorsal surface: Smooth and convex, providing passage for extensor tendons.

    • Plantar surface: Concave and roughened for attachment of plantar interossei and ligaments.

    • Sides: Provide attachment to interosseous muscles.

  • Cortex: Thick cortical shell, particularly along the plantar aspect, designed for weight-bearing.

  • Marrow cavity: Contains fatty marrow in adults, continuous with base and head cavities.

Relations

  • Dorsally: Extensor tendons (extensor digitorum longus and brevis, extensor hallucis longus)

  • Plantar surface: Flexor tendons (flexor digitorum longus and brevis, flexor hallucis longus) and plantar aponeurosis

  • Medially and laterally: Interosseous muscles and neurovascular bundles

  • Proximally: Base articulates with tarsal bones and adjacent metatarsals

  • Distally: Head articulates with proximal phalanx

Attachments

  • Dorsal surface: Interosseous muscles and extensor tendons pass along grooves

  • Plantar surface: Plantar interossei and fibrous slips of plantar aponeurosis

  • Lateral and medial aspects: Collateral ligaments of the metatarsophalangeal joints near distal end

  • Base (continuity): Dorsal and plantar tarsometatarsal ligaments

  • Periosteum: Serves as attachment for deep fascia and intrinsic foot musculature

Nerve Supply

  • Periosteum and surrounding soft tissues: Supplied by digital branches of the deep fibular, medial plantar, and lateral plantar nerves depending on location

Arterial Supply

  • Dorsal metatarsal arteries (from arcuate artery, branch of dorsalis pedis)

  • Plantar metatarsal arteries (from deep plantar arch)

  • Nutrient artery: Enters posterior third of shaft to supply the medullary cavity

Venous Drainage

  • Dorsal metatarsal veins draining into the dorsal venous arch

  • Plantar venous plexus connecting to posterior tibial veins

Function

  • Weight-bearing: Transmits body weight from tarsus to phalanges during stance and gait

  • Lever arm: Provides mechanical leverage for propulsion in walking and running

  • Force distribution: Maintains arches of the foot by acting as struts between tarsus and toes

  • Attachment site: Serves as anchor for muscles, fascia, and ligaments contributing to stability

Clinical Significance

  • Fractures: Common in trauma (direct impact, twisting), stress fractures (metatarsal shaft stress reaction in runners, dancers)

  • Periostitis: Inflammatory reaction due to repetitive strain

  • Osteomyelitis: May occur secondary to penetrating injury or diabetic ulcer

  • Deformities: Metatarsalgia, metatarsus primus elevatus, and callosity formation from altered weight-bearing

  • Imaging role: MRI and CT are key in diagnosing stress reactions, cortical defects, and healing response

MRI Appearance

  • T1-weighted images:

    • Cortex: Low signal (dark)

    • Bone marrow: Bright (fatty marrow signal)

    • Muscle: Intermediate signal

    • Periosteum: Thin low-signal line surrounding cortex

    • Fracture or stress reaction: Linear low-signal band crossing cortex and marrow with adjacent marrow edema

  • T2-weighted images:

    • Cortex: Low signal (dark)

    • Marrow: Bright, slightly lower intensity than on T1 but still hyperintense relative to muscle

    • Periosteal reaction: Low-to-intermediate signal thickening around shaft

    • Pathology: Stress edema or fracture line shows high T2 signal with low-signal fracture plane

  • STIR:

    • Normal marrow: Intermediate-to-dark signal

    • Abnormal marrow: Bright hyperintense areas indicating edema, stress reaction, infection, or tumor

    • Excellent for detecting early bone stress injuries before cortical changes appear on CT

  • Proton Density Fat-Saturated (PD FS):

    • Normal marrow: Intermediate-to-dark signal

    • Pathology: Bright hyperintensity in marrow or periosteum indicates stress edema or inflammatory changes

    • Ideal for subtle cortical stress fractures, periostitis, or osteitis

  • T1 Fat-Sat Post-Contrast:

    • Normal bone: Mild uniform enhancement

    • Active inflammation or infection: Patchy marrow and periosteal enhancement

    • Healing fracture: Linear peripheral enhancement surrounding low-signal fracture line

    • Chronic sclerosis: Minimal or no enhancement

CT Appearance

Non-Contrast CT:

  • Cortex: Dense, sharply defined high attenuation

  • Trabecular pattern: Fine, regular structure within marrow cavity

  • Pathology: Clearly visualizes cortical fractures, periosteal reaction, sclerosis, or callus formation

  • Stress fracture: May appear as subtle cortical lucency or thickening before displacement occurs

  • Useful for: Post-traumatic assessment, surgical planning, and evaluation of bone integrity

Post-Contrast CT (standard):

  • Normal bone: Mild enhancement of vascularized marrow

  • Pathologic enhancement: Seen in infection, inflammation, or neoplastic infiltration

  • Periosteal enhancement: Suggestive of osteomyelitis or healing response

  • Soft-tissue enhancement: Correlates with abscess or reactive inflammation

MRI image

body of metatarsal bone coronal cross sectional anatomy 3T MRI AI enhanced radiology image-img-00000-00000

MRI image

Body of metatarsal bone SAG cross sectional anatomy 3T MRI AI enhanced radiology image-img-00000-00000

CT image

body of metatarsal bone sagittal ct image