the ossification of long bones begins in the primary.
the ossification of long bones begins in the primary.
where does the ossification of long bones begin?
in the primary
endochondral ossification begins with points in the cartilage called "primary ossification centers." they mostly appear during fetal development, though a few short bones begin their primary ossification after birth. they are responsible for the formation of the diaphyses of long bones, short bones and certain parts of irregular bones. secondary ossification occurs after birth, and forms the epiphyses of long bones and the extremities of irregular and flat bones. the diaphysis and both epiphyses of a long bone are separated by a growing zone of cartilage (the epiphyseal plate). at skeletal maturity (18 to 25 years of age), all of the cartilage is replaced by bone, fusing the diaphysis and both epiphyses together (epiphyseal closure). in the upper limbs, only the diaphyses of the long bones and scapula are ossified. the epiphyses, carpal bones, coracoid process, medial border of the scapula, and acromion are still cartilaginous.
bone
opsismodysplasia can be characterized by a delay in bone maturation, which refers to "bone aging", an expected sequence of developmental changes in the skeleton corresponding to the chronological age of a person. factors such as gender and ethnicity also play a role in bone age assessment. the only indicator of physical development that can be applied from birth through mature adulthood is bone age. specifically, the age and maturity of bone can be determined by its state of ossification, the age-related process whereby certain cartilaginous and soft tissue structures are transformed into bone. the condition of epiphyseal plates (growth plates) at the ends of the long bones (which includes those of the arms, hands, legs and feet) is another measurement of bone age. the evaluation of both ossification and the state of growth plates in children is often reached through radiography (x-rays) of the carpals (bones of the hand and wrist). in opsismodysplasia, the process of ossification in long bones can be disrupted by a failure of ossification centers (a center of organization in long bones, where cartilage cells designated to await and undergo ossification gather and align in rows) to form. this was observed in a 16-month-old boy with the disorder, who had no apparent ossification centers in the carpals (bones of the hand and wrist) or tarsals (bones of the foot). this was associated with an absence of ossification in these bones, as well as disfigurement of the hands and feet at age two. the boy also had no ossification occurring in the lower femur (thigh bone) and upper tibia (the shin bone).
opsismodysplasia