This is no longer a useful distinction. The structure of the skeleton is a balance between efficient weight distribution, strength and calcium homeostasis. The skeleton is designed to provide the strength needed for normal daily stresses at the minimum bone mass. With advancing age there is progressive loss of both trabecular and cortical bone, due to an imbalance between bone resorption and formation. In women, trabecular bone loss occurs by thinning, perforation and loss of connectivity.
Cortical thinning is the result of endocortical bone resorption.
A particular example of this is corticosteroid osteoporosis. Although osteoporotic fractures are often thought of more specifically in terms of wrist, hip or spinal fractures, it is important to remember that virtually any bone can fracture in an individual with osteoporosis. Fractures of bones in the upper and lower limbs, ribs, spine and pelvis are more numerous and generally occur in younger individuals than do hip fractures. Although osteoporotic fractures heal normally, from middle age onwards each is associated with significant morbidity and varying degrees of long term disability, since the skeletal deformity may be permanent. Moreover, the occurrence of one fracture is associated with an increased risk of further osteoporotic fractures.