Library · Physiology
Synovial fluid
Make it clearer
Synovial fluid is the fluid that fills the joint space, the gap inside the joint.
It is not made from nothing: it comes from the blood. It is an ultrafiltrate of plasma, that is, strained plasma, and it is secreted by certain cells in the joint, the type B synovial cells, which look like fibroblasts.
It does two jobs at once. It lubricates the articular cartilage, the smooth layer that covers the ends of the bones, and it also feeds that cartilage: by diffusion, meaning slow passage through the fluid, it carries nutrients to the cartilage, the meniscus and the labrum, which cushion the joint. It is the oil in a hinge that also feeds the hinge.
And it is not always the same. Its amount and its contents change when there is trauma, inflammation or the entry of bacteria, fungi or viruses.
In brief
Synovial fluid is the fluid held within the space of a joint.
It is produced as an ultrafiltrate of plasma and secreted by type B synovial cells, which resemble fibroblasts.
It lubricates the articular cartilage and, by diffusion, nourishes the cartilage, the meniscus and the labrum.
The oil in a hinge that also feeds the hinge.
Its volume and contents change with trauma, inflammation or the entry of bacteria, fungi or viruses.
Sources (1)
- National Center for Biotechnology Information, StatPearls PublishingSynovial Fluid Analysis, StatPearlsPublished
This page explains the topic in general terms; it does not tell anyone what treatment to follow.
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