The First Histological Analysis of the Tissues Lining the Fossa Navicularis: Insights to its Etiology.

The fossa navicularis (FN) is an anatomical variant on the ventral surface of the basilar part of the occipital bone that, to date, has only been investigated in bone specimens. We aim to clarify the structure of the fossa navicularis by gross anatomical, radiological, and histological methods. The FN was found in the occipital bone of the Caucasian male cadaver. There was no bony or histological continuity between the FN and posterior cranial fossa. The histological analysis found that the overlying tissue was composed of loose connective tissue with a mixture of collagen and elastic fibers and a vascular matrix including arteries, veins, and capillaries. There was no evidence of lymphoid, glandular, or notochordal tissues. As no previous studies have performed histological analysis of the FN, this report adds to our knowledge of tissues that are involved in its formation.