Humerus fracture also cause deformity, and they typically limit the ability to flex the elbow. Humerus fractures usually occur after physical trauma, falls, excess physical stress, or pathological conditions. Falls that produce humerus fractures among the elderly are usually accompanied by a preexisting risk factor for bone fracture, such as osteoporosis, a low bone density, or vitamin B deficiency. Proximal humerus fractures most often occur among elderly people with osteoporosis who fall on an outstretched arm. Less frequently, proximal fractures occur from motor vehicle accidents, gunshots, and violent muscle contractions from an electric shock or seizure. Other risk factors for proximal fractures
Bone as osteoblasts and osteoclasts. Within any single bone, the tissue is woven into two main patterns, known cortical and cancellous bone, and each with different appearance and characteristics. The hard outer layer of bones is composed of cortical bone also called compact bone being much denser than cancellous bone. It forms the hard exterior (cortex) of bones. The cortical bone gives bone its smooth, white, and solid appearance, and accounts for 80% of the total bone mass of an adult human skeleton. It facilitates bone's main functions: to support the whole body, protect organs, provide levers for movement, and store