Anatomic and radiographic appearance of a sesamoid bone in the tendon of origin of the supinator muscle of the cat.

Results of radiologic and anatomic studies of each cubital articulation (elbow) of a group of 50 adult cat cadavers indicated that a sesamoid bone may be located in a constantly present sesamoid cartilage associated with the tendon of origin of the supinator muscle. Radiography revealed a sesamoid bone in 40 of the 100 tendons of origin of the supinator muscles dissected from the elbows. The sesamoid bone articulated with the craniolateral aspect of the head of the radius, and the larger sesamoid cartilage, which contained the bone, articulated with the head of the radius and the capitulum of the humerus. Of several possible functions of the sesamoid cartilage (bone), it was considered that protection of the craniolateral part of the humeroradial articulation and maintenance of the complex anatomic system during joint movement were important. In radiographic views of the elbows of lame cats, the sesamoid bone should not be mistaken for a chip fracture or an osteocartilaginous loose body.