Basic calcium phosphate and pyrophosphate calcium crystals are the 2 main 
calcium-containing crystals that can deposit in all skeletal tissues. These 
calcium crystals give rise to numerous manifestations, including acute 
inflammatory attacks that can mimic alarming and threatening differential 
diagnoses, osteoarthritis-like lesions, destructive arthropathies, and calcific 
tendinitis. Awareness of uncommon localizations and manifestations such as 
intraspinal deposition (eg, crowned dens syndrome, tendinitis of longus colli 
muscle, massive cervical myelopathy compression) prevents inappropriate 
procedures and cares. Coupling plain radiography, ultrasonography, computed 
tomography, and synovial fluid analysis allow accurate diagnosis by directly or 
indirectly identifying the GRAAL of microcrystal-related symptoms.