Yes birds do have knees but they are not where you would expect them.
A few facts circulate within zoology that are simply not true. One of the worst offenders is that birds’ knees are on backwards.
Admittedly there does seem to be a joint where you’d expect to see the knee, and it does appear to bend in the opposite direction. However, what you’re actually seeing is the ankle joint, which is very high up on the leg.
Birds have relatively short femurs (thigh bones), and the knees are actually tucked right up against the body, nestled among the wings and feathers.
Kneecaps are sesamoid bones, meaning that they grow within a tendon, probably to protect the sinews from general wear and tear.
What is sometimes mistakenly thought of as the typical lower leg bones (the tibia and fibula) is the tarsometatarsus, a single fusion of ankle and foot bones found only in birds and certain dinosaurs.
Birds are true digitigrades, meaning that they walk with only their toes on the ground. The rest of the foot just happens to extend up the leg, giving rise to the claims of backwards knees.
The flightless ostrich is the only animal to bear twice the regulation number of kneecaps.
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