"Patella cubiti, also known as os sesamoideum tricipitale is a very rare anomaly of the elbow, presenting as a sesamoid within the distal triceps brachii tendon. Its exact aetiology is unknown with congenital, developmental and post-traumatic theories postulated 1."
"lateral elbow projection: has a similar appearance to the patella; well-corticated with smooth rounded edges with an otherwise normal elbow joint 1"