Seen in rickets A/E -
Ans. is 'c' i.e., Epiphyseal dysgenesiso In rickets osteoid (protein matrix) is formed normally but mineralization of this osteoid does not occur i.e. there is defective mineralization.o Epiphyseal plate (growth plate) has following five zones (moving from epiphysis towards metaphysis) -i) Resting zoneii) Proliferative zoneiii) Maturation zoneiv) Zone of hyperophyv) Zone of provisional calcificationo Normally, capillaries grow from metaphysis to epiphysis tunnels in the zone of provisional calcification. This ingrowth of capillaries destroy the cailagenous cells in zone of hyperophy, thereby limiting the growth of epiphyseal plate.Changes in Ricketso In rickets, tunnels are not formed in zone of provisional calcification because there is defective mineralization No capillary ingrowth from metaphysis to epiphysis ---> cailagenous cells continue to proliferate but do not die --> Thickening of growth plate.o Proliferating cells in growth plate extend beyond the normal width of bone --> widning of growth plate (clinically presents as palpable enlargement at wrist, elbow and ankle, also at costochondral junction -4 rachitic rosary).o As there is softening of metaphysis, axial pressure pushes the epiphysis into the metaphysis cupping or flaring of metaphysis (In normal bones, metaphysis is rigid so cupping does not occur).o As there is irregular calcification (mineralization), the edge of the metaphysis loses its sharp border --> fraying of metaphysis.In subperiosteal region, calcium deposition in the osteoid surrounding the shaft is impaired --> softening and deformity of long bones.
Cupping of metaphysis
Defective Mineralization
Epiphyseal dysgenesis
All