Write down the embryological development of all 3 layer of Tympanic Membrane?

The tympanic membrane is formed by the opposition of two epithelia provided by External Auditory Canal (EAC)  and the middle ear cavity, with the fibrous layer between them. Embroyologically originates from the epithelia of the EAC and the endoderm of the corresponding branchial pouch respectively. The fibrous layer originates from the branchial and mensenchyme.

 

Summary :

Epithelium of EAC -> Ectoderm of 1^st branchail cleft.

Epithelium of middle ear cavity -> endoderm of 1^st  branchial pouch.

Fibrous layer ->  1^st branchial arch mesenchyme.

 

 

The dorsal part of the fist bronchial groove which gives rise to EAC, progressively deepens during the 2^nd month. The ectoderm of the groove briefly about on the endoderm of the tub0tympanic recess ( 1^st pharyngeal pouch ) , but during the 6^th week , a mesodermal ingrowth breaks this contact.

 

 

 

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