The sagittal grooves of the middle nasal turbinate determine paradoxical curvatures and bifidities.

BACKGROUND: Paradoxical curvature of the middle nasal turbinate (MT) is a common anatomic variant, usually found and reported on coronal CT slices. However, less attention has been paid to the sagittal groove (SG) which is determining it. AIM: The study aimed to determine paradoxical curvatures and bifidities in the sagittal groves of middle nasal turbinate. MATERIAL AND METHOD: A retrospective CBCT study on the archived files of 52 adult patients was performed. RESULTS: Different patterns of MT bifidity were found: (1) unilateral bifid MTs; (2) bifid and trifid MTs and "wandering" single SGs; (3) bilateral bifid middle turbinates and double SGs, (4) bilateral false bifid appearance due to middle and superior turbinates fusion and (5) bifid concha bullosa media. Digital "dissections" of patients' files allowed us to conclude that paradoxical curvature as well as bifidity of MTs relate to the placement and number of the SGs on the MTs. Such SGs were previously documented in prenatal MTs since the 14th week, as well as in pædiatric patients. CONCLUSIONS: It seems reasonable to speculate that paradoxical curvature, as well as bifidity of MT, this later being previously undocumented, are just adult vestiges of the primitive MT morphology. Nevertheless, documentation of the MT morphology should not rely exclusively on coronal CTs, as combined morphologies of that turbinate could occur.

Bifid and secondary superior nasal turbinates.

The lateral nasal wall contains the nasal turbinates (conchae) which are used as landmarks during functional endoscopic surgery. Various morphological pos- sibilities of turbinates were reported, such as bifidity of the inferior turbinate and extra middle turbinates, such as the secondary middle turbinate. During a retrospective cone beam computed tomography study of nasal turbinates in a patient we found previously unreported variants of the superior nasal turbina- tes. These had, bilaterally, ethmoidal and sphenoidal insertions. On the right side we found a bifid superior turbinate and on the left side we found a secondary superior turbinate located beneath the normal/principal one, in the superior nasal meatus. These demonstrate that if a variant morphology is possible for a certain turbinate, it could occur in any nasal turbinate but it has not been yet observed or reported.

Rare anatomic variation: Giant unilateral concha bullosa superior.

The lateral nasal wall attaches the nasal turbinates, which could be, either pneumatized, or paradoxically curved. The turbinate pneumatization-concha bullosausually indicates the pneumatization of the middle turbinate. However, concha bullosasuperior (CBS) is also, although rare, anatomic possibility of variation. We report here a case of unilateral giant septated CBS, which was not, to our knowledge, previously reported. The case was documented in Cone Beam Computed Tomography (CBCT). Subtle pneumatizations of inferior turbinates were found bilateral, as also were the middle conchae bullosae. The left concha bullosasuperior was very large (17.43/5.34mm), dropping down between the left middle turbinate and the contralaterally deviated nasal septum, and contacting the paradoxical curvature of the middle turbinate on that side. An incomplete oblique septum divided it incompletely into anterior and posterior chambers, it was communicating with a posterior ethmoid air cell, and was draining in the superior meatus. Care should be taken not to misdiagnose a giant CBS as a middle turbinate pneumatization, in order not to misjudge surgical corridors. Therefore, a careful anatomic CT or CBCT diagnosis would be of use for the plan of treatment.

Vertical and sagittal combinations of concha bullosa media and paradoxical middle turbinate.

Common anatomic variants of the middle nasal turbinate include its pneumatization (i.e. concha bullosa media) and its paradoxical curvature. We report here two cases of differently combined variations of the middle turbinate which were documented in cone beam computed tomography (CBCT). The first report presents the vertical combination of a double or septated lamellar concha bullosa with the paradoxical curvature of middle turbinate. This combined variant associated (coincidental findings): ipsilateral paradoxical superior turbinate and contralateral paradoxical middle turbinate, concha bullosa superior and concha bullosa suprema. In the second case was found the sagittal combination of successive anterior concha bullosa media and posterior paradoxical curvature of the middle turbinate. An ethmoidal sinolith was found embedded in lamella basalis. The contralateral superior turbinate was pneumatized. These rare findings demonstrate that sound knowledge of possible anatomical variations, supported by a complete use of the tools available for the CBCT documentation of cases, is able to enrich the picture of human anatomic variations, with a direct impact on clinical and surgical practice. The septa-containing lamellar concha bullosa and paradoxical middle concha combination is a variation that affects surgical practice.

Rare anatomic variation: true bifid inferior turbinate.

Nasal anatomic variations are relevant during nasal surgical and endoscopic procedures. The extent of imaging methods, such as the cone beam computed tomography (CBCT), allows a better characterization of such peculiar anatomic traits. The bifid inferior turbinate (BIT) is a rare finding, being previously reported less than ten times. It was found and described on CT scans of patients, being usually associated with the absence of the uncinate process (UP). We hereby report for the first time a bilateral true BIT which differs from the previously reported BITs by the fact that the UPs were present and the bifidity was oriented laterally. In the light of this new find, we consider that the variant resulted from UP displacement should be regarded as a false bifid, or double, inferior turbinate. Bifidity of the inferior turbinate was not previously evaluated in CBCT, as well as in three-dimensional volume renderizations. So, CBCT proves as an efficient tool to investigate prevalence of rare anatomical variants. Noteworthy, CT studies of patients on a case-by-case basis allows a better performance of surgical and endoscopic procedures.