Supratubal recess in neonates and infants

The fetal development of the supratubal recess and of the tensor fold was described by Hammar in 1902. Recent studies claim that neither structure is regularly present in neonates and controversial views have been presented of the separation of the anterior attic and supratubal recess. The objective of this study is to clarify these issues.

Twenty temporal bones, 13 neonate and seven infant, were studied either by microdissection of fresh (five bones) or formalin stored (two) specimens, or by serial sectioning after formalin fixation and decalcification (13 bones). The serial sections were cut to 20 microm, every tenth section saved and stained by hematoxylin eosin.

In all specimens the separating structure between the anterior attic and supratubal recess was the tensor fold. It was intact in 15 bones while five showed a membrane defect. In vertically oriented folds the recess was deep and in horizontally oriented folds shallow. In 19 bones the tensor fold inserted superiorly to a soft tissue insertion ring of varying thickness and only once directly to a shallow transverse crest. The breadth of the tensor fold near the tensor tendon showed only little variation, whereas its height, and the distance from the tensor tendon to the supratubal tegmen varied in larger limits.

The tensor fold and the supratubal recess are present already in the neonate and thus develop during the fetal period. The shape of the recess is determined by the fold direction and its size grows in conjunction with the other middle ear spaces. The transverse crest has no apparent influence on the position of the tensor fold. The easiest method to study the integrated whole of the anterior attic and supratubal recess is to view them alternatively from the anterior and superior microdissection approaches. Clinically, removal of the tensor fold creates an efficient additional aeration route from the supratubal recess to the anterior attic.