May Be Caused by

 Common

Ankylosing spondylitis

Avulsive trauma

Calcium pyrophosphate dihydrate crystal deposition disease

Diffuse idiopathic skeletal hyperostosis

Idiopathic

Pellegrini-Stieda disease

Peritendinitis calcarea

Physiologic degenerative change

Psoriatic arthritis

Reiter syndrome

Sternocostoclavicular hyperostosis

 Uncommon

Alkaptonuria

Aponeurotic-type fibromatosis

Calcinosis universalis

Cis-retinoic acid

De Quervain disease

Fibrodysplasia ossificans progressiva

Fibromatosis

Fluorosis

Gout

Hypervitaminosis A

Hypervitaminosis D

Multicentric infantile myofibromatosis

Pyoderma gangrenosum

Renal osteodystrophy

Rheumatoid arthritis

 Rare

Ganglion