In children, the femoral head and neck are joined by a cartilaginous epiphyseal plate, and can separate from each other along this line when stress is applied to the bone. This is called an epiphyseal fracture. In adulthood, the two parts of the bone are united by osseous tissue and not as easily separated. Adolescents are especially at risk of epiphyseal fractures because their greater body weight (compared to younger children) puts more stress on the femur and their participation in sports and rough play, and their relatively high frequency of vehicular accidents, subject them to more trauma.
High-heeled shoes lift the calcaneus off the ground and give the foot an angle similar to that of a dog or cat. However, the weight of the body is still partially supported through the calcaneus and the heel of the shoe, whereas in a dog or cat, it must be supported entirely on the heads of the metatarsals.
In both the carpal and tarsal groups, the distal row is composed of four bones, although there are no similarities in their names: the hamate, capitate, trapezoid, and trapezium in the wrist, and the first to third cuneiforms and the cuboid in the foot. In the proximal row, the wrist has four bones and the ankle has three: the scaphoid, lunate, triquetral, and pisiform in the wrist, and the navicular, talus, and calcaneus in the ankle. (Note that the scaphoid of the wrist is also called the navicular, so under this nomenclature, there is a navicular bone in both places.) The three proximal tarsal bones do not form a transverse row like the proximal bones of the wrist.
The fibula is often used for bone grafts because it does not support the weight of the body and is more dispensable than any of the other long bones of the lower limb.
Andy could have fractured the tibiae or the femoral shafts, but since the EMT said he had broken his hips, the most likely site would be the necks of the femurs. (A fractured acetabulum is also possible.) Andy was able to jump from such heights as a child without injury because a child’s bones are more resilient and because a child, being lighter in weight, hits the ground with less momentum (force) than an adult, so the landing produces less stress on the bones.
