ABSTRACT
Sesamoid and accessory bones are small, oval-shaped structures that develop within tendons that pass over bony prominences. Although rare, accessory bones in the elbow region hold clinical significance because they can cause diagnostic uncertainty. We present the case of a 47-year-old previously healthy female patient who presented with left elbow pain and was discovered to have a sesamoid bone distal to the medial epicondyle of the humerus. On examination, the patient's left elbow was tender, but her range of motion was in normal range. Plain radiographs identified a small, oval-shaped bony fragment; further radiographic investigations were conducted. Computed tomography and ultrasound were performed to rule out diagnostic uncertainties. A diagnosis of os subepicondylare mediale, a rare sesamoid bone, was established through a thorough investigation of the well-circumscribed structure in accordance with the most current literature.
