Fossa navicularis: Anatomic variation at the skull base

The fossa navicularis is a relatively rare anatomic variation of the skull base. Awareness of its existence will avoid misinterpretations of radiological images and unnecessary investigations. This study describes the appearance of the fossa navicularis, and investigates its incidence and whether it is related to pathology at the basiocciput. We studied 492 dry human skulls and 525 computer tomography (CT) images of patients. Dry skulls showing a fossa navicularis were investigated by CT scan, whereas patients identified as having a fossa navicularis were further examined with magnetic resonance imaging (MRI). To document the position of the fossa more precisely, measurements were made between the fossa navicularis and certain anatomic landmarks such as the foramen ovale, the pharyngeal tubercle, the posterior border of the vomer, the foramen lacerum, the carotid canal, and the occipital condyle. Upon examination, 26 of 492 skulls (5.3%) were found to have a fossa navicularis. Twelve were <2 mm in depth and the other 14 had a depth of ≥2 mm. Of the 525 patients, 16 (3.0%) were identified as having a fossa navicularis in CT images. Evaluation of MRIs showed no soft tissue lesions in any of these patients. Comprehensive anatomic details of the fossa navicularis have not been reported in the literature. The results of this study may be useful to radiologists, anatomists, and surgeons interested in the skull base. Clin. Anat. 17:118–122, 2004. © 2004 Wiley‐Liss, Inc.

[1]  L. Scheuer Application of osteology to forensic medicine , 2002, Clinical anatomy.

[2]  P. Romanet,et al.  [MRI screening of vestibular schwannomas without gadolinium: usefulness of the turbo gradient spin echo T2-weighted pulse sequence]. , 2001, Journal of neuroradiology. Journal de neuroradiologie.

[3]  V. Chong,et al.  Radiology of the nasopharynx: pictorial essay. , 2000, Australasian radiology.

[4]  P. Mullaney,et al.  Canalis basilaris medianus: MRI , 2000, Neuroradiology.

[5]  M. Takahashi,et al.  MR imaging of Tornwaldt's cysts. , 1999, AJR. American journal of roentgenology.

[6]  G. Hunt,et al.  Nasopharyngeal obstruction due to cystic Rathke's clefts in two dogs. , 1999, Australian veterinary journal.

[7]  A. Beltramello,et al.  Fossa navicularis magna. , 1998, AJNR. American journal of neuroradiology.

[8]  H. Miyahara,et al.  Tornwaldt's disease. , 1994, Acta oto-laryngologica. Supplementum.

[9]  L. Burgess,et al.  Tornwaldt's Cyst: Case Report with Magnetic Resonance Imaging (MRI) , 1990, Otolaryngology--head and neck surgery : official journal of American Academy of Otolaryngology-Head and Neck Surgery.

[10]  G. Currarino Canalis basilaris medianus and related defects of the basiocciput. , 1988, AJNR. American journal of neuroradiology.

[11]  M. Hawke,et al.  Tornwaldt's cyst: clinical and radiological aspects. , 1987, The Journal of otolaryngology.

[12]  R. H. Miller,et al.  Tornwaldt's bursa. , 1985, Clinical otolaryngology and allied sciences.

[13]  K. Maravilla,et al.  Transsphenoidal canal (large craniopharyngeal canal) and its pathologic implications. , 1985, AJNR. American journal of neuroradiology.

[14]  J. Dietemann,et al.  Calcified remnants of the notochord in the roof of the nasopharynx. , 1980, Radiology.

[15]  H. Schaupp,et al.  [The pathogenesis of the nasopharyngeal bursa (Tornwaldt's disease) (author's transl)]. , 1975, HNO.

[16]  L. Stern,et al.  Tornwaldt's disease , 1972, Neurology.

[17]  L. B. Arey The craniopharyngeal canal reviewed and reinterpreted , 1950, The Anatomical record.

[18]  H. B. Collins Frequency and distribution of fossa pharyngea in human crania , 1927 .