Tam o' Shanter sign (skull)

Paget’s Disease

Tam o’ Shanter sign (skull) | Radiology Reference Article | Radiopaedia.org


  1. ↑ serum alkaline phosphatase
  2. Normal calcium and phosphorus levels
  3. ↑ urine hydroxyproline

Radiographic features


→ Osteoporosis circumscripta, Cotton wool appearance, Diploic widening

→ Tam o’ shanter sign: platybasia and basilar invagination


→ Picture frame sign, Squaring of vertebrae, Vertical trabecular thickening


→ Pelvic brim sign and leads to obliteration of köhler’s​ teardrop

→ Acetabular protrusion

Long bones

→ Blade of grass or candle flame sign, Lateral curvature of femur

→ Anterior curvature of the tibia

Picture frame vertebral body | Radiology Reference Article | Radiopaedia.orgThe Blade of Grass Sign | RadiologyPelvic Brim Sign & obliteration of Köhler’s​ teardrop in pagetoid pelvis - cortical thickening and sclerosis of the iliopectineal and ilioisc… | Pelvis, Brim, Signs