Collagen type I is the most abundant collagen type in the annulus fibrosus (AF).

Collagen type I is indeed the most abundant collagen type found in the annulus fibrosus (AF), which is part of the intervertebral disc in the spine. The annulus fibrosus serves to provide strength and support to the disc, maintaining its structural integrity and resistance to tensile forces. This collagen type contributes to the tensile strength and durability of the AF, allowing it to withstand the mechanical stresses that occur during movement and load-bearing activities.

Collagen type II is also present within the intervertebral disc, particularly in the nucleus pulposus, where it supports a more gel-like consistency, but type I predominates in the AF. Therefore, affirming that collagen type I is the most abundant collagen type in the annulus fibrosus aligns with the known composition and functional requirements of this tissue in maintaining spinal health and function.