Bone Disorders

Bone homeostasis is a delicate balance between bone tissue resorption by osteoclasts and deposition by osteoblasts.

Any factor that disrupts this balance can lead to bone disorders.

For example, vitamin D deficiency in the body reduces calcium absorption from blood, affecting bone mineralization by osteoblasts.

The resulting weak and soft bones can lead to pain and deformities like bowed legs and soft skull, a condition termed rickets in children.

In adults, it can cause osteomalacia or adult rickets, characterized by pain in the hip and legs.

With age, reduced osteoblast  activity and decreased bone mineral density fail to compensate for the bone loss by osteoclast activity, resulting in osteopenia.

Severe osteopenia can lead to osteoporosis— porous bones with compromised bone strength, which can fracture even under everyday mechanical stress.  

Lastly, in Paget's disease, osteoclasts proliferate haphazardly, and to balance the excessive bone resorption, osteoblasts speed up the bone deposition.

Such weak bones have a higher proportion of spongy  bone over compact bone with abnormal thickenings, causing pain and deformity.