What is Wormian bones are not noted in - and explain in detail?
Wormian bones 

Wormian bones are extra bone pieces that occur within a suture in the cranium.
These are irregular isolated bones which appear in addition to the usual centres of ossification of the cranium.
They occur most frequently in the course of the lambdoid suture.
Causes of Wormian bones (Mnemonic - PORKCHOPS)


Pyknodysostosis
Osteogenesis imperfecta
Rickets
Kinky hair syndrome
Cleidocranial dysostosis
Hypothyroidism (cretinism) / Hypophosphatasia
Otopalatodigital syndrome
Progeria
Syndrome of Downs


Wormian bone appears radiographically as islands of ossification in the skull in non ossified membranous bone.
To be diagnostic value, the wormian bones should be 4 mm by 6 mm in size, 10 in number and arranged in a mosaic pattern.
Wormian bones are not present in the normal skull.