Gilulas Lines

Other Names

Radiograph demonstrating Gilula’s lines. Line I represents the proximal articular surfaces of the proximal carpal row. Line II represents the distal articular surfaces of the first carpal row. Line III represents the proximal articular surfaces of the distal carpal row. Disruption of these lines is indicative of a boney (greater arc) or ligamentous (lesser arc) injury.

• Gilula’s arcs
• Gilula carpal arcs
• Gilula three carpal arcs
• Three carpal arcs
• Carpal arcs
• Carpal alignment arcs
• Carpal alignment lines
• Gilula lines

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Introduction

(A) Gilula lines describe 3 smooth arcs that transcribe the proximal articular surfaces of the proximal carpal row (I), the distal articular surfaces of the proximal carpal row (II), and the proximal articular surface of the hamate and capitate (III). (B) In this minimally displaced distal radius fracture, Gilula first line is broken and is suspicious for a scapholunate ligament injury. (C) Clenched fist view demonstrates widening of the scapholunate interval consistent with a complete tear. (D) Carpal height (L2) and length of third metacarpal (L1). The carpal height ratio (0.54 AE 0.03) is derived from L2/L1.

Introduction

• Gilula’s lines are three smooth, continuous arcs used to assess carpal alignment on wrist radiographs
• First described by Louis A. Gilula (1979)
• Drawn along the proximal and distal contours of the carpal bones
• Normal finding: smooth, uninterrupted curves with no step-off
• Disruption indicates carpal instability, ligament injury, or fracture-dislocation
• Acts similarly to a “screening sign”—like a fat pad sign—indicating underlying injury

Description of the Three Arcs

• Arc I: Proximal convex surfaces of scaphoid, lunate, triquetrum
• Arc II: Distal concave surfaces of scaphoid, lunate, triquetrum
• Arc III: Proximal convex surfaces of capitate and hamate
• All arcs should form parallel, continuous curves without interruption

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Standard Views

• Best visualized on:
  • PA (posteroanterior) wrist radiograph → primary view
  • AP view (less commonly used but acceptable equivalent)
• Not assessed on:
  • Lateral view (used instead for radius–lunate–capitate alignment)
• PA view is essential for identifying:
  • Breaks in Gilula’s arcs
  • Carpal spacing abnormalities

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Pediatrics

PA radiographs demonstrating disruption of Gilula arcs, increased scapholunate interval, increased overlap of the carpals, and the abnormally triangular appearance of the lunate, also known as the "piece of pie" sign (right). Normal PA wrist (left) for comparison.

• Incomplete ossification of carpal bones can:
  • Make arcs difficult to interpret
  • Mimic pathology or pseudo-disruption
• Normal measurements differ:
  • Scapholunate interval <2 mm in adults
  • Not reliable in children due to cartilaginous structures
• Developmental variants:
  • Accessory ossicles (e.g., os epilunatum)
  • Partial fusions (e.g., lunotriquetral coalition)
• Pediatric wrists require correlation with age and ossification stage

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Abnormal Findings

• Step-off or discontinuity in any arc
  • Indicates loss of normal carpal alignment
• Widening between carpal bones
  • Suggests ligament disruption (e.g., scapholunate injury)
• Overlap of carpal bones
  • Seen in perilunate dislocations
• Arc disruption correlates with dislocation
  • Strong association with carpal dislocations and fracture-dislocations
• Early detection:
  • Helps identify occult or subtle injuries before obvious deformity
• Missed disruptions can lead to:
  • Chronic instability
  • Arthritis
  • Avascular necrosis

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Pathology

• Carpal instability
  • Scapholunate Dissociation
  • Lunotriquetral Instability
• Perilunate injuries
  • Perilunate Dislocation
  • Lunate Dislocation
• Fracture-dislocations
  • Trans Scaphoid Perilunate Dislocation
• Carpal Fractures
  • Scaphoid Fractures
  • Triquetral Fractures
• Ligamentous injuries
  • Disruption of intrinsic carpal ligaments

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See Also

• Radiology Main
• Wrist Pain Main

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