Do Dogs Have Knees?

Dogs do have knees on their hindlegs, known as the stifle joint which is made up of three bones; the femur, patella (knee cap) and tibia. The patella is a small plate-like sesamoid bone located in front of the stifle joint and is embedded in the rides in the tendon of the quadriceps femoris, connecting the muscles in the front of the thigh to the femur (thigh bone) and tibia (shin bone). The kneecap (patella) protects the knee joint, lengthens the lever arm of the quadriceps femoris, and increases the area of contact between the patellar ligament and the femur.

Close up of a dog's stifle (knee) joint

What is the function of the canine knee?

The knee is a complicated hinge joint that is made up of bones, muscles, ligaments, tendons and meniscus. It allows the leg to bend (flexion) and straighten (extend), as well as allowing the femur to rotate inward or outward.

Do dogs have two or four legs?

Skeleton

Dogs are quadrupeds, which means they walk on all four legs. The hind legs are at the rear and the forelegs at the front. The foreleg joints include a wrist and an elbow as well as biceps and triceps located in the upper foreleg.

Unlike humans, who walk on their entire foot (plantigrade), dogs (and cats) walk on their toes (digitigrade).

Disorders of the canine knee

Luxating patella

As with humans, the canine knee can develop a number of disorders due to injury, age or congenital.

  • Luxating patella: A condition in which the kneecap (patellar) moves (or dislocates) out of the trochlear groove, and moves to the inside (medial) or outside (lateral) of the knee joint (known as the stifle joint in cats). Medial luxation is more common than lateral. Unresolved patellar luxation can lead to arthritis.
  • Cruciate ligament rupture: A rupture of the ligaments that attach the femur (thigh bone) with the tibia (shinbone), the long bones above and below the knee joint ( stifle joint).
  • Arthritis: A condition characterised by the breakdown of the joints and surrounding tissues. Cartilage is the smooth, slippery tissue over the ends of the bones in the joints which acts as a cushion and shock absorber, allowing the bones to glide over each other. When arthritis develops, this slippery layer breaks down and wears away exposing the bones causing pain, inflammation, and stiffness. As the disease progresses, loss of movement can occur in the affected joint.
  • Fracture of the patella: A break in the kneecap (patella), most often associated with a traumatic injury such as a fall.