Anatomical and radiological observations of the sesamoid bone of the popliteus muscle in the adult dog and cat.

In a random selection of 50 adult dogs (25 males and 25 females) and 50 adult cats (25 males and 25 females), the incidence of ossification of the sesamoid structure of the popliteus muscle was characterized through anatomical dissection and radiographic techniques. The incidence of ossification was 84% in the dogs and 100% in the cats. In both anatomical and radiologic studies, it was demonstrated that when the knee was fully extended, the sesamoid bone was adjacent to the caudodistal part of the articular surface of the lateral tibial condyle in both dogs and cats. When the knee was flexed, the sesamoid bone articulated progressively with the more craniodorsal part of the tibial articular surface and when full flexion is obtained, it articulated with the articular part of the lateral surface of the lateral meniscus. The probable functions of the sesamoid bone are discussed.