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 cyst who called these lesions "homerus ossifying haematoma". In 1940 Ewing used the term "aneurismal" to describe these lesions. Jaffé and Lichtenstein first coined the term "aneurismal cyst" in 1942 In 1950 they modified this term to "aneurismal bone cyst". They may be associated with bone tumors. The simple bone cyst is a common, benign, fluid-containing lesion, most commonly found in the metaphysis of long bones, typically the proximal humerus or femur. Pathologic fractures are common, often with minor trauma. These cysts typically resolve after skeletal maturity and are not typically associated with bone tumors. The cause is unknown. These were