Growth and Development: Musculoskeletal Development

how does growth differ from development

growth is an increase in size while development is structural and functional maturation

when do we see limb buds

week 4 prenatal

when do we see cartilaginous model of skeleton

week 6 prenatal

when does endochondral ossification begin

week 7 prenatal

when are primary ossification centers present in all long bones

12 weeks

what is ossification? when does it occur?

process by which bone forms; initial formation, juvenile bone growth, bone remodeling, bone repair

what is calcification

part of ossification where tissue hardens through mineral deposition

steps of intramembranous ossification

mesenchymal cells cluster, cells differentiate into osteogenic cells, become osteoblasts, deposit and calcify bone matrix

what bones are formed via intramembranous ossification

flat bones, facial bones, mandible, medial clavicle

how do most bones form

endochondral ossification

steps of endochondral ossification

cartilage model forms, primary ossification (diaphysis) center forms, secondary ossification (epiphyses) form, growth plate remains between

two forms of bone growth

longitudinal bone growth, appositional bone growth

what is bone modeling

coordinated formation and resorption of bone that shapes it into its mature form

what drives bone modeling

nutrition, hormones, heredity, mechanical forces

what is bone deformation

abnormalities in form/shape/position in body parts caused by unusual mechanical forces during growth

mechanical forces that influence skeletal modeling

compression, tension, torque, uneven forces across growth plates

what occurs with intermittent, appropriate force

bone growth increases longitudinally and appositionally

what occurs with decreased muscle pull

less bone growth, shorter limb length

what occurs with excessive/constant loads

slowed bone growth, resorption of bone

what occurs with uneven force across a growth plate

asymmetrical growth and angulation of bone (convex on one side, concave on the other)

how does torque influence bone grwoth

twisting or shearing alters rotational shape

when do most females growth plates close (epiphyseal plates)

14-18 years