Horse Side Vet Guide ®

Equine Health Resource

Cerebrospinal Fluid Collection & Analysis



A clear, colorless fluid called cerebro-spinal fluid bathes the brain and spinal cord. It is produced and resorbed in a specific area of the brain and circulates through a specific path. It protects the brain and spinal cord mechanically and chemically.

The gross appearance of the fluid and specific laboratory values are evaluated to determine the health of the brain and spinal cord.

In the horse, this fluid is most commonly sampled from one of two sites:

The lumbo-sacral (L-S) space is in front of the highest point of the hip. Sampling of fluid here is a standing procedure. It requires sedation and a 6-8″ long needle.

The atlanto-occipital space is a site between the skull and the first neck vertebrae. Sampling here requires general anesthesia and a shorter needle. It is a quick and simple procedure.


Brain and spinal cord diseases may be reflected in the changes found within cerebro-spinal fluid.

Antibodies and infectious agents found within the cerebro-spinal fluid may help confirm that in fact the brain or spinal cord has been infected with a particular agent.


Injuries to the inner parts of the brain and spinal cord may not be reflected in the fluid.

Fluid changes may not be as obvious when fluid is sampled from a site very distant from a focal area of injury.

Sampling may be difficult in some cases at the L-S space.

Contamination of fluid samples with blood may make the diagnostics performed of less value.

Author: Doug Thal DVM Dipl. ABVP


We're not around right now. But you can send us an email and we'll get back to you, asap.