Interrod enamel is histologically

Histology

Histology is the study of the microscopic anatomy of cells and tissues of plants and animals. It is performed by examining cells and tissues commonly by sectioning and staining; followed by examination under a light microscope or electron microscope...

 identified on microscopic views of tooth enamel

Tooth enamel

Tooth enamel, along with dentin, cementum, and dental pulp is one of the four major tissues that make up the tooth in vertebrates. It is the hardest and most highly mineralized substance in the human body. Tooth enamel is also found in the dermal denticles of sharks...

. Because interrod enamel is located around enamel rod

Enamel rod

An Enamel rod is the basic unit of tooth enamel. Measuring 4 μm wide to 8 μm high, an enamel rod is a tightly packed, highly organized mass of hydroxyapatite crystals...

s, the areas of interrod enamel enhances the "keyhole" appearance of enamel rods by acting as its border. The location where the two areas of enamel meet is known as the rod sheath

Rod sheath

Rod sheath is an area identified in histologic sections of a tooth. It is found where enamel rods, the functional unit of enamel, meet interrod enamel. The crystals of both types of enamel meet at sharp angles and form the appearance of a space called the rod sheath. As a result of this space,...

.

All tooth enamel, including interrod enamel and enamel rods, is made by ameloblast

Ameloblast

Ameloblasts are cells, present only during tooth development, that deposit tooth enamel, the hard outermost layer of the tooth that forms the chewing surface....

s. However, interrod enamel is formed slightly sooner than enamel rods.

Interrod enamel has the same composition as enamel rods. A distinction is made between the two because they differ in the direction of their crystalline patterns.