Radial Styloid Ossicle

Description

There is a cleft epiphysis of the ulna and a persistent radial styloid. Both are normal variants and not fractures

A) X-ray AP view of left wrist showing a small well defined rounded corticated bone (yellow arrow) with normal trabecular pattern adjacent to lateral aspect of radial head and distal pole of scaphoid. B) Coronal, C) Axial and D) Sagittal Reformatted Non Contrast CT images of left wrist showing the presence of a well defined, small, rounded bone with distinct trabecular pattern and peripheral cortex (yellow arrow), distal and lateral to the radial head without any evidence of sclerosis or cortical breech. Associated subchondral sclerosis is seen in distal end of radius (black arrow). E) Coronal and F) Axial Non Contrast CT images of normal appearing right wrist.

Name

• Os Radiostyloideum
• Persistent radial styloid
• Accessory ossicle of the radial styloid
• Radial styloid accessory bone
• Accessory radial styloid ossicle
• Os styloideum radii (rare)

General

• Small accessory ossicle adjacent to the radial styloid process
• Accessory ossicle of the wrist
• Located adjacent to the radial styloid, lateral to mid scaphoid
• Can be confused with os styloideum
• Typically well-corticated and rounded on imaging
• Located at the distal radius near the radiocarpal joint
• Represents a developmental variant from a secondary ossification center

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Clinical Significance

• Often an incidental finding on wrist imaging
• Can mimic an avulsion fracture of the radial styloid after trauma
• May be associated with localized radial-sided wrist pain if symptomatic
• Important to differentiate from acute fracture to avoid unnecessary treatment

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See Also

• Hand And Wrist Anatomy
• Physical Exam Hand
• Wrist Pain Main

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