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Fifth metatarsal bone

The fifth metatarsal bone is the long bone on the lateral side of the foot, articulating proximally with the cuboid and distally with the proximal phalanx of the little toe. It serves as a critical structural element for lateral foot stability, load transfer, and muscle attachment.

The base of the bone features a prominent tuberosity, which provides the insertion for the peroneus brevis and peroneus tertius tendons. This region is clinically significant due to its vulnerability to avulsion (pseudo-Jones) fractures, Jones fractures, and stress fractures — all of which have distinct imaging appearances and prognostic implications.

Synonyms

  • Metatarsal V

  • Fifth ray bone

Location and Articulations

  • Location: Lateral aspect of the foot, forming the fifth ray between the cuboid and proximal phalanx of the fifth toe

  • Proximal articulation: Cuboid bone (at the fifth tarsometatarsal joint)

  • Distal articulation: Base of the proximal phalanx of the fifth toe

  • Medial articulation: Fourth metatarsal base (via intermetatarsal joint)

Surfaces and Features

  • Base: Expanded and rough, giving rise to the styloid (tuberosity) on its lateral side for tendon attachment

  • Shaft: Slender and slightly curved; serves as an important lever during gait

  • Head: Small and convex, articulating with the base of the proximal phalanx

  • Dorsal surface: Rough for ligament attachment

  • Plantar surface: Smooth, forming part of the weight-bearing surface

Attachments

  • Peroneus brevis tendon: Inserts onto the lateral tuberosity (styloid process) of the base

  • Peroneus tertius tendon: Inserts near the dorsal surface of the base or shaft

  • Plantar aponeurosis: Attaches to the plantar aspect of the head

  • Interosseous ligaments: Link to the fourth metatarsal

  • Dorsal and plantar tarsometatarsal ligaments: Strengthen the cuboid–metatarsal joint

Relations

  • Superiorly: Dorsalis pedis artery and dorsal cutaneous nerves

  • Inferiorly: Plantar fascia and lateral plantar vessels

  • Medially: Fourth metatarsal

  • Laterally: Peroneus brevis and tertius tendons overlie its tuberosity

  • Posteriorly: Cuboid bone

  • Anteriorly: Fifth toe proximal phalanx

Arterial Supply

  • Dorsalis pedis artery: via lateral tarsal and arcuate branches

  • Perforating branches from the plantar metatarsal arteries

  • Nutrient artery: Penetrates the shaft, supplying the medullary cavity

Venous Drainage

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

Function

  • Structural support: Forms the lateral border of the forefoot

  • Muscle leverage: Provides attachment for peroneus brevis and tertius, aiding eversion and dorsiflexion

  • Weight transfer: Conveys forces from lateral foot to toes during gait

  • Balance and propulsion: Contributes to push-off stability during walking and running

Clinical Significance

  • Avulsion fracture (pseudo-Jones): At styloid tuberosity due to peroneus brevis pull

  • Jones fracture: Transverse fracture at metaphyseal–diaphyseal junction; poor healing due to limited blood supply

  • Stress fractures: Common in athletes, typically at the shaft; related to repetitive strain

  • Accessory ossicle (os vesalianum): May mimic avulsion fracture

  • Imaging role: MRI and CT are essential for early detection of stress injuries and fracture classification

MRI Appearance

  • T1-weighted images:

    • Normal marrow: bright signal intensity due to fatty content

    • Cortex: low signal (dark rim)

    • Fracture: linear or irregular low-signal line with surrounding marrow edema

    • Chronic sclerosis: low signal with adjacent fatty bright marrow

  • T2-weighted images:

    • Normal marrow: bright signal, varying with fat content (less intense than subcutaneous fat)

    • Cortex: dark

    • Acute fracture or stress reaction: bright marrow edema replacing normal fat

    • Healing: peripheral bright callus surrounding darker cortical line

  • STIR (Short Tau Inversion Recovery):

    • Normal marrow: dark (signal suppressed)

    • Pathology: bright hyperintense signal indicating marrow edema, stress fracture, or infection

  • Proton Density Fat-Saturated (PD FS):

    • Normal marrow: dark

    • Pathology: bright signal in marrow or periosteum (bone bruise, stress injury, osteomyelitis)

    • Useful for differentiating edema vs sclerosis and evaluating tendon attachments

  • T1 Fat-Sat Post-Contrast:

    • Normal bone: mild homogeneous enhancement

    • Fracture or infection: heterogeneous or peripheral enhancement around marrow edema

    • Chronic necrosis or sclerosis: minimal or absent enhancement

CT Appearance

Non-Contrast CT:

  • High-resolution detail of cortical and trabecular bone

  • Fractures: clearly seen as cortical breaks or lucent lines

  • Stress fractures: subtle linear lucencies or cortical thickening

  • Chronic injury: sclerotic healing, periosteal reaction, or callus formation

  • Accessory ossicles: smooth corticated margins distinguish them from acute fractures

Post-Contrast CT (standard):

  • Limited added value for bone

  • Enhancement seen in active infection, healing, or inflammation

  • Best for assessing fracture alignment, nonunion, or post-surgical healing

CT VRT 3D image

fifth Metatarsal Bone ct vrt

MRI image

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MRI image

fifth metatarsal bone axial cross sectional anatomy 3T MRI AI enhanced radiology image-img-00000-00000_00001

CT image

fifth Metatarsal Bone ct axial

CT image

fifth Metatarsal Bone ct sag