crista
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which is the embryological origin?
i have a doubt bz in HY first they say stapedius,incus and maleus have the origin in neural crest cells and in ear capter they say their origins are in pharyngeal arches 1+2.
could somebody explain, please...
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| mjl1717
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First the Arches have mesodemal and neural crest derivatives, a unique aspect of neural crest cells is that they can form non neural tissue.
The neural component of arch 1 is bone or cartilage in the mandibular area it is the mandible incus malleus sphenomandiular ligament and anterior ligament of the malleus
In the 2nd arch the mesoderm component forms m. of facial expression, posterior belly of digastric, stylohyoid muscle and stapedius muscle.
The main point is that each arch has derivatives from somitomeric mesoderm which forms muscles and Neural crest derivatives that form bone or cartilage. Hope this helps.
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| crista
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I don't have enough words to thank you. 
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| usmleasr
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cool mjl ..good explanation 8)
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| Pardeep Kumar
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Pl try to understand the basic concept of Branchail arches. In fact now they are all called Pharyngeal arches. Each arch has its own ectodermal, endodermal and mesodermal derivative. Neural crest cells enter into these arch for Induction purpose. failure to which leads to amny syndromes.
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