Abnormal Congenital Location of Stapes’ Superstructure: Clinical and Embryological Implications

Table 1

Classification of congenital anomalies of the middle ear. Adapted from Teunissen and Cremers [15].

Class	Main anomaly	Subclassification
1	Congenital stapes ankylosis
2	Stapes ankylosis associated with another congenital ossicular chain anomaly
3	Congenital anomaly of the ossicular chain but mobile stapes footplate	(A) Discontinuity in ossicular chain; (B) Epitympanic fixation
4	Congenital aplasia or severe dysplasia of oval window or round window	(A) Aplasia; (B) Dysplasia; (i) Crossing facial nerve; (ii) Persistent stapedial artery