Template:Hearing timeline table
From Embryology
Developmental Time | Event |
---|---|
Week 9 | Mesenchyme surrounding membranous labryinth (otic capsule) chondrifies. |
Week 12-16 | Capsule adjacent to membranous labryinth undegoes vacuolization to form a cavity (perilymphatic space) around membranous labrynth and fills with perilymph. |
Week 18 | ectodermal plug in external auditory meatus breaks down. |
Week 16 - 24 | Centres of endochondral ossification appear in remaining cartilage of otic capsule form petrous portion of temporal bone. Continues to ossify to form mastoid process of temporal bone. |
Week 18 - 22 | Organ of corti structural elements develop. (GA 20 - 24 weeks) |
26 weeks | human brainstem auditory pathway is anatomically formed. |
28 weeks | AABR can be recorded. |
3rd Trimester | Vibration acoustically of maternal abdominal wall induces startle response in fetus. |
Links: hearing | timeline |