Each intervertebral fibrocartilage is composed, at its circumference, of laminæ of fibrous tissue and 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...

, forming the annulus fibrosus.

Spelling notes

Both "anulus" and "annulus" are acceptable spellings. Gray's Anatomy

Gray's Anatomy

Gray's Anatomy is an English-language human anatomy textbook originally written by Henry Gray. The book is widely regarded as an extremely influential work on the subject, and has continued to be revised and republished from its initial publication in 1858 to the present day...

 uses "annulus fibrosus," Terminologia Anatomica

Terminologia Anatomica

Terminologia Anatomica is the international standard on human anatomic terminology. It was developed by the Federative Committee on Anatomical Terminology and the International Federation of Associations of Anatomists and was released in 1998. It supersedes the previous standard, Nomina...

 uses "anulus fibrosus," and Nomina Anatomica

Nomina Anatomica

In the late nineteenth century some 50,000 terms for various body parts were in use. The same structures were described by different names, depending on the anatomist’s school and national tradition. Vernacular translations of Latin and Greek, as well as various eponymous terms, were barriers to...

uses both forms. Etymologically speaking, anulus seems to be the correct spelling as it is the diminutive of L. anus, a ring, hence anulus, a little ring.

"Fibrosus" has no correct alternative spelling; "fibrosis" has a different meaning and is incorrect in this context.

External links

• Diagram at upenn.edu
• Diagram at spineuniverse.com