when do limb buds develop during pregnancy
A. Much of the initial growth and patterning of the limbs occurs during weeks 4 â 8. Limb buds appear at about 4 weeks and much of the basic structures of the limbs (bones and muscle groups) are established by 8 weeks. After 8 weeks, the limb elements then just increase in size. B. Disruption of growth and/or patterning can result in many possible defects: