The fabella is the sesamoid bone in the stifle joint of a dog. Here, you will know the answer to the question – ‘Where is the fabella on a dog?’.
Quick answer: The dog’s lateral and medial fabellae are above the corresponding condyle at the distal-caudal aspect of the femur bone. They work as the sesamoids for the dog’s gastrocnemius muscles.
Here, I will describe the location of the lateral and medial fabella from a dog femur bone with a diagram. You will also know the unique features of these sesamoid bones from the dog’s hindlimb.
What is the fabella in a dog?
The stifle joint of a dog possesses three sesamoid bones. Here, the cranial one is the larger sesamoid bone called the patella. Again, the caudal two sesamoid bones are the fabella on a dog.
These caudal two sesamoids or fabella are little bean-like structures. They possess all the typical features of the sesamoid bones.
Key features of the fabella as the sesamoid bones –
- They develop in the capsule of the stifle joint or tendons of the gastrocnemius muscle,
- Fabella of the dog diminishes the friction in the stifle joint,
- They change the direction of the tendons of the gastrocnemius and popliteus muscles,
- Finally, these fabellae of the dog increase the leverage of the gastrocnemius muscles and its tendon.
The diagram shows the lateral and medial fabella from the cauda-distal part of the dog femur bone.
Where is the fabella on a dog?
The fabellae of the dog are located in the head of the gastrocnemius muscle caudal to the stifle joint on the lateral and medial condyle.
Let’s notice the osteological features of the condyles from the dog femur bone. The caudal aspect of the lateral and medial condyles of the dog femur show facet for the corresponding fabella.
You will find little difference between the medial and lateral fabella of the dog. Let’s see the unique features of the medial and lateral fabella of the dog’s stifle joint in the next section of this article.
Lateral fabella on a dog
The lateral fabella of a dog is larger than the medial fabella. This lateral fabella develops with the origin of the lateral head of the dog’s gastrocnemius muscle.
You will also find the following osteological features on the lateral fabella of a dog –
- The lateral fabella is a spherical shape in a dog,
- It possesses a truncated end that faces distally,
- The dog’s lateral fabella has nearly a flat articular surface for articulation with the caudal surface of the lateral condyle,
Medial fabella on a dog
A dog’s medial fabella is smaller than the lateral fabella. It develops with the origin of the medial head of the gastrocnemius muscle.
Let’s see the other different osteological features of the dog’s medical fabella –
- The lateral fabella is small and angular in form,
- The articular surface of the lateral fabella is not distinct,
- It attaches to the caudal surface of the medial condyle of the dog femur bone,
Other sesamoids in the dog’s stifle joint
You will also find another sesamoid bone in the dog’s stifle joint. It is very small and intercalated in the tendon of origin of the popliteus muscle.
Thus, this small bone develops with the muscle fibres of the dog’s popliteus. This small sesamoid bone articulates with the lateral condyle of the dog femur on its caudal aspect.
Suggested article on the sesamoid bone from anatomy learner:
So, the fabellae are two sesamoid bones above the corresponding condyles of the dog femur bone. They develop with the lateral and medial gastrocnemius muscle tendons and increase leverage to these tendons.