The sulcular epithelium is that epithelium which lines the gingival sulcus of the mouth near the teeth. It is marked by F in the link below.

is a clinical term in dentistry. CAL = the depth measured from the CEJ (cemento-enamel junction) to the bottom of the gingival sulcus. It indicates the amount of attachment that has been lost

Gingival fluid is fluid containing plasma proteins. When there is gingival inflammation more gingival fluid is produced. Gingival fluid is sometimes also called crevicular fluid.

If you're referring to the cortex of bone, that would be trabeculae.

The answer is sulcus.