What Is Ganglion Impar?

The Ganglion Impar is the lowest cluster of nerve bodies located just in front of the bottom of the tailbone behind the rectum. This is the boney area called the coccyx, located below the sacrum.

A group of sympathetic nerves forms this ganglionic cluster of nerves. Nerves leave the ganglion and travel to blood vessels and other structures near the tailbone, rectal area, perianal area, urethra, and vaginal area.


Ganglion impar block Overview

Nerve blocks of this ganglion are useful for painful conditions in the above mentioned areas including trauma, cancer, degenerative changes, fracture, and occasionally infections.

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Before and After the Procedure and the Risks


These procedures are done usually with x-ray guidance.

The patient is positioned facedown and x-ray images are taken of the coccyx from the top and from the side. A local anesthetic, numbing solution, is injected gently over the tailbone and a short blunt tip needle is gently advanced between the bones of the coccyx to travel just in front. This is where the ganglion sits.


The needle tip position is confirmed by injecting a small amount of contrast, x-ray Ink, which shows a dark  crescent appearance in front of the coccyx and behind the rectum.


local anesthetic with or without steroid is injected in the area and the needle is removed and area is cleaned and a bandage is applied.

After the Procedure

The patient is discharged home the same day with instructions to keep the area clean and the bandage in place for at least 12 hours.

Ice can be applied for any local pain.

The effects from the local anesthetic can often be immediate, the steroid can provide relief a day later.

Relief of pain after this injection indicates that the ganglionic sympathetic nerves are responsible for the perceived pain.

This means that this injection is both diagnostic and therapeutic.


Your physician will want to see you after 1 to 2 weeks to determine if a second injection is necessary.

Procedure Risks

The risks from this procedure are surprisingly minimal.

As with all injections involving puncturing the skin, the risks of bleeding and infection are possible though less than 5%.