The lingual septum consists of a vertical layer of fibrous tissue, extending throughout the entire length of the median plane

Median plane

The median plane is a Midsagittal plane which bisects the body vertically through the navel, dividing the body exactly in left and right side.Sagittal plane is any plane parallel to the median plane....

 of the tongue

Tongue

The tongue is a muscular hydrostat on the floors of the mouths of most vertebrates which manipulates food for mastication. It is the primary organ of taste , as much of the upper surface of the tongue is covered in papillae and taste buds. It is sensitive and kept moist by saliva, and is richly...

, though not quite reaching the dorsum

Dorsum (biology)

In anatomy, the dorsum is the upper side of animals that typically run, fly, or swim in a horizontal position, and the back side of animals that walk upright. In vertebrates the dorsum contains the backbone. The term dorsal refers to anatomical structures that are either situated toward or grow...

.

It is thicker behind than in front, and occasionally contains a small fibrocartilage

Fibrocartilage

White fibrocartilage consists of a mixture of white fibrous tissue and cartilaginous tissue in various proportions. It owes its flexibility and toughness to the former of these constituents, and its elasticity to the latter...

, about 6 mm. in length.

It is well displayed by making a vertical section across the organ.