Clinical Features and Radiological Differential Diagnoses of Symptomatic Sesamoid Bones and Accessory Ossicles: A Pictorial Essay

Sesamoid bones and accessory ossicles are normal anatomic variants with varying morphological appearances and incidences. They are usually small osseous fragments with well-corticated margins located adjacent to the joint space and bone. Patients with sesamoid bones and accessory ossicles are usually asymptomatic and commonly encountered in clinical practice. These sesamoids and accessory bones are occasionally painful because of fractures, dislocations, degenerative changes, avascular necrosis, accessory bone infections, or abnormalities of the adjacent tissue, such as nerve entrapment, tenosynovitis, or soft tissue impingement. This article aimed to illustrate the imaging features of symptomatic sesamoids bones and accessory ossicles at various anatomic locations and describe their clinical features and radiological differential diagnosis.