What is inside a gum pocket?

What the drawing is measured from

1. Plaque never reaches the bone: on 48 extracted teeth the front of the plaque lay 0.2 to 2.0 mm from the remaining attachment fibres, and in autopsy material never less than 0.5 mm or more than 2.7 mm from the bone. DOI 1
2. Inside a pocket, between the last epithelium and the first intact fibres there was a zone of destroyed fibres averaging 0.43 mm wide, in almost every tooth examined. DOI 2
3. The pocket lining does not attach to the tooth: it is thin, ridged and full of inflammatory cells, with breaks in places (a study of experimental pockets in dogs). DOI 3
4. Tartar always carries plaque: a living film of plaque covers mineralised tartar deposits, above and below the gum. DOI 4
5. Two kinds of tartar: above the gum it is yellow-white, layered and about 37% mineral by volume; below the gum it is dark brown, uniform and about 58% mineral, usually a thin, smooth veneer on the root (Friskopp and Isacsson 1984; Woelfel; Gurgan and Bilgin 2005). DOI 5
6. Where the probe stops in a pocket: in untreated pockets the tip went 0.29 mm (Magnusson and Listgarten 1980) and 0.45 mm (Fowler 1982) past the epithelium into inflamed tissue, well short of the bone; after treatment it stopped inside the epithelium. DOI 6
7. The tooth: a lower central incisor in section, crown 9.5 mm and root 12.5 mm (Wheeler's Dental Anatomy, Table 7.1), with the lip side on the left. Pockets and openings are drawn slightly open so they can be seen; no number on the drawing is a measurement of one person.