Radiographic and Ultrasonographic Evaluation of the Rare Sesamoid Bone of the Elbow: Os Subepicondylare Mediale

Abstract

Background: Sesamoids and accessory bones are generally small-sized and oval-shaped structures whose function and pathology are not fully elucidated. Despite their small size, sesamoid bones can directly or indirectly cause diagnostic problems. Sesamoid bones are less common in the elbow region and may need to be differentiated from a lot of diagnoses such as fractures, osteochondritis dissecans, calcific tendinitis, and synovial chondromatosis.

Case presentation: A 55-year-old female patient presented with right elbow pain. An oval mass was seen near the medial epicondyle on the radiograph. A dynamic ultrasound examination was performed to reveal the relationship between the bone mass and the surrounding tissues, especially the ulnar nerve. Due to the well-circumscribed mass, a diagnosis of os subepicodlare mediale, a rare sesamoid bone, was made in light of current literature.

Conclusions: When a bone mass is seen in patients presenting with elbow pain, it will be useful to know and consider the sesamoid bones. In addition, ultrasonography should be performed in addition to radiography for a localized sesamoid bone in the medial region and adjacent to the ulnar nerve. Thus, the relationship of the sesamoid bone with existing and potential complaints can be revealed and correct diagnosis-treatment approaches can be applied.

Keywords: Accessory ossicles; elbow pain; lateral epicondylitis; medial epicondylitis; ulnar nerve.