Topics

Topic

design image
Body of the metatarsal bone

The body (shaft) of the metatarsal bone is the elongated middle portion between the base and the head of each metatarsal. There are five metatarsal bones in the foot, forming the bony framework of the forefoot and playing a crucial role in weight transmission, propulsion, and balance.

Each metatarsal body is slender and slightly concave on its plantar aspect, giving strength and elasticity to the arches of the foot. The first metatarsal is the shortest and strongest, while the second metatarsal is the longest and most rigidly fixed, making it prone to stress fractures.

The cortical bone is thick along the diaphysis, enclosing fat-rich cancellous marrow, which appears bright on MRI. The metatarsal bodies serve as key load-bearing and lever structures during gait and are common sites of stress injuries, fractures, and bone marrow edema.

Synonyms

  • Shaft of metatarsal bone

  • Metatarsal diaphysis

Location and Structure

  • Location: Between the base (proximal end) and head (distal end) of the metatarsal bones in the forefoot

  • Shape: Slightly curved shaft; convex dorsally and concave plantarly

  • Surfaces:

    • Dorsal surface: smooth and subcutaneous

    • Plantar surface: concave, providing attachment for interosseous muscles and ligaments

  • Borders: Lateral and medial borders provide attachment to interossei and fibrous septa

Attachments

  • Dorsal interossei muscles: Attach to the sides of metatarsal bodies (2nd–4th)

  • Plantar interossei muscles: Arise from medial sides of 3rd–5th metatarsals

  • Interosseous fascia and ligaments: Strengthen metatarsal spaces and stabilize transverse arch

  • Tendinous sheaths: Extensor tendons run dorsally; flexor tendons plantarly

Relations

  • Dorsally: Dorsal interossei muscles and dorsal metatarsal arteries

  • Plantarly: Plantar interossei muscles, plantar fascia, and deep plantar arteries

  • Laterally and medially: Adjacent metatarsal bones and interosseous spaces

  • Proximally: Base articulates with tarsal bones (cuneiforms, cuboid)

  • Distally: Head articulates with the proximal phalanges of toes

Arterial Supply

  • Dorsal metatarsal arteries (branches of dorsalis pedis)

  • Plantar metatarsal arteries (branches of lateral plantar artery)

  • Nutrient arteries enter through the diaphyseal cortex to supply marrow

Venous Drainage

  • Dorsal venous arch and plantar venous plexus, draining into the great saphenous and posterior tibial veins

Nerve Supply

  • Dorsally: Deep and superficial fibular nerves

  • Plantarly: Medial and lateral plantar nerves (branches of tibial nerve)

Function

  • Weight transmission: Distributes body weight during standing and walking

  • Propulsion: Acts as a lever during toe-off phase of gait

  • Arch support: Contributes to transverse and longitudinal arches of the foot

  • Attachment site: Provides origins and insertions for muscles maintaining foot stability

Clinical Significance

  • Fractures: Common in athletes; 5th metatarsal (Jones fracture) and 2nd metatarsal (stress fracture) most frequent

  • Stress reactions: Result from repetitive microtrauma; appear as marrow edema before cortical break

  • Osteomyelitis: Infections often spread from soft tissues or ulcers in diabetics

  • Tumors and cysts: Rare but can involve the diaphysis

  • Imaging role: MRI detects early marrow changes; CT identifies cortical disruptions and fracture healing

MRI Appearance

  • T1-weighted images:

    • Normal marrow: bright signal intensity, depending on fat content (more fatty = brighter)

    • Cortex: low signal (dark thin rim)

    • Stress fracture or marrow edema: focal or diffuse low signal replacing fatty marrow

    • Muscle and tendons appear intermediate in comparison

  • T2-weighted images:

    • Normal marrow: bright signal, though slightly less than subcutaneous fat

    • Cortex: dark outline

    • Edema or fracture: hyperintense (bright) areas within or around the marrow

    • Periosteal reaction: bright linear signal along cortical surface

  • STIR (Short Tau Inversion Recovery):

    • Normal marrow: dark signal (fat suppressed)

    • Pathology: bright hyperintense signal indicating bone bruise, edema, infection, or stress injury

    • Excellent for early detection of stress-related bone changes

  • Proton Density Fat-Saturated (PD FS):

    • Normal marrow: dark due to fat suppression

    • Pathologic marrow: bright signal from edema or inflammatory infiltration

    • Highlights periosteal and soft tissue edema around fractures

  • T1 Fat-Sat Post-Contrast:

    • Normal: minimal enhancement

    • Infection or inflammation: enhancing marrow and periosteum

    • Chronic sclerosis: poor or absent enhancement

CT Appearance

Non-Contrast CT:

  • Clearly shows cortical thickness and trabecular pattern

  • Fractures: visible as lucent lines or cortical disruptions

  • Stress fractures: may present as focal sclerosis or periosteal thickening

  • Osteomyelitis: cortical erosion, periosteal new bone formation, and sequestra visible

  • Healing fractures: bridging callus and trabecular continuity

Post-Contrast CT (standard):

  • Limited value for bone marrow itself

  • May highlight periosteal reaction, soft tissue abscess, or infection

  • Useful for surgical planning and assessing cortical integrity

CT VRT 3D image

body (shaft) of the metatarsal bone ct a3d vert image

MRI image

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

CT image

body (shaft) of the metatarsal bone ct sag image