Sellar spine corresponds to a rare variant of the sella turcica bony structure characterized by a mid-line spur that projects anteriorly from the dorsum sellae. It has no clinical significance, but it may be confused with a hypophyseal nodule (e.g. microadenoma) on low-resolution MRI images, especially on coronal planes.
When large, the sellar spine can contain bone marrow and thus appear as a T1 hyperintense lesion.
It is believed to represent ossification of the remnant of the anterior end of the notochord 3.