The lower limb bones are built for bearing weight and walking. The femur is the longest and strongest bone in the body.
The femur
The head of the femur fits into the acetabulum and is joined to the shaft by the neck. Hip fractures in older adults usually happen at the neck or between the trochanters.
Knee and patella
The patella is a sesamoid bone inside the quadriceps tendon that improves the muscle's leverage. The knee joint is formed by the femur and tibia, not the fibula.
Tibia and fibula
The tibia carries the body's weight and lies just under the skin of the shin, so open fractures are common. The thin fibula on the outer side mainly anchors muscles and forms the outer ankle.
The foot
Seven tarsal bones, including the talus and calcaneus, five metatarsals and 14 phalanges form the foot. Its arches spread the load and absorb shock with every step.
At the bedside
A shortened, externally rotated leg after a fall suggests a hip fracture. For ankle and foot injuries, the Ottawa rules use bone tenderness at the malleoli, the base of the fifth metatarsal and the navicular, plus inability to bear weight, to decide who needs an X-ray.
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Written by Making Synapses. Topic reference: OpenStax, Anatomy and Physiology 2e (no text adapted).