Template:Hearing timeline
From Embryology
| Stage | 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 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. |
