What do shunts look like? Understanding the internal and external appearance

September 28, 2025 •

4 min read

According to the Hydrocephalus Association, over 1 million Americans live with hydrocephalus, with the majority relying on a shunt system for treatment. For those unfamiliar, the question, "What do shunts look like?" often arises, as these life-saving medical devices are primarily hidden beneath the skin.

Quick Summary

A medical shunt is a system of flexible, thin tubes (catheters) connected by a small valve, all implanted under the skin to reroute excess cerebrospinal fluid. Externally, this may result in a faint scar, a visible or palpable bump where the valve sits, and a subtle line tracing the tubing's path.

Key Points

Internal Device: Shunts are entirely internal, consisting of thin tubes (catheters) and a valve placed under the skin to divert excess cerebrospinal fluid.
External Signs: Visible signs include healed surgical scars, and potentially a palpable bump or subtle outline of the valve and tubing beneath the skin.
Primary Components: The system includes a proximal catheter, a valve, and a distal catheter that typically drains fluid to the abdominal cavity.
Variable Visibility: How much a shunt is seen or felt depends on the individual's body fat, skin thickness, hair, and the surgeon's specific placement.
Evolution of Valves: Modern programmable valves allow doctors to adjust pressure settings non-invasively, in contrast to older, fixed-pressure models.
Minimal Impact: Despite being a permanent implant, shunts have a minimal external impact, allowing most patients to live normal, active lives.

Components of a Medical Shunt System

To understand what shunts look like, it is important to first familiarize yourself with the parts that make up the system. A typical shunt consists of several key components working together to manage cerebrospinal fluid (CSF) flow.

The Catheters

The catheters are soft, flexible tubes, typically made of silicone, that transport the CSF. The shunt system includes two main catheters:

Proximal catheter: The inlet tube, which is inserted into the CSF-filled space, most often one of the brain's ventricles.
Distal catheter: The outlet tube, which is tunneled under the skin to a drainage site in another part of the body, such as the abdominal cavity or heart.

The Valve

The valve is the central mechanism that controls the flow and pressure of the CSF. It is a small, disc-like device, often placed behind the ear, on the side of the head, or sometimes near the collarbone. The valve is designed to open when the pressure of the CSF exceeds a certain level, allowing fluid to drain, and to close when the pressure returns to normal.

The Reservoir

Some shunts include a reservoir, which is a small, domed chamber attached to the valve. It allows neurosurgeons to access and withdraw a CSF sample if necessary. A reservoir may appear as a small, soft bulge under the skin, separate from the main valve.

What You Might See and Feel Externally

Because the entire shunt system is placed internally, it is not always obvious what shunts look like from the outside. The visible and palpable signs are typically minimal.

The Incisions and Scars

During surgery, a neurosurgeon makes a few incisions to implant the shunt. These are typically located:

On the scalp to access the ventricle.
Behind the ear or on the side of the head for the valve placement.
On the neck, chest, or abdomen to create a path for the distal catheter.

Over time, these incisions heal and may leave small, thin scars. The visibility of the scars can vary depending on the patient's skin type, hair coverage, and the size of the initial incision.

The Valve and Tubing

For many patients, the most noticeable aspect of a shunt system is the small bulge or bump from the valve and reservoir under the skin. In children, whose skin is often thinner, this bump may be more prominent. The tubing of the catheter can sometimes be felt as a thin, cord-like structure just beneath the skin as it travels down the neck and torso. The degree of visibility is highly dependent on an individual's body fat percentage and the specific placement chosen by the surgeon.

Visible Tubing: The line of the distal catheter can sometimes be seen, especially when a person bends or stretches. It may appear as a fine line snaking down the side of the neck or chest.
Valve Bump: In individuals with short hair or little scalp fat, the valve can be quite visible, resembling a small disc or square beneath the skin. Newer technologies, such as cranial implant casings, can help minimize this bump by sitting flush with the skull.

Types of Shunts and Their Drainage Sites

The primary difference between various shunts is the drainage site for the CSF, which affects the path of the distal catheter. Here are the most common types:

Ventriculoperitoneal (VP) Shunt: The most common type, this shunt directs CSF from the brain's ventricles to the peritoneal cavity (the space around the abdominal organs), where it is absorbed naturally.
Ventriculoatrial (VA) Shunt: Used less frequently, a VA shunt routes the CSF from the brain to the atrium of the heart. The catheter is tunneled down the neck and into a vein.
Lumboperitoneal (LP) Shunt: For cases of communicating hydrocephalus, an LP shunt drains CSF from the lumbar (lower spine) region to the abdomen.

Comparing Shunt Valve Technology

Shunt technology has evolved significantly, with different types of valves impacting the system's function and, in some cases, its feel under the skin. Here is a comparison of two primary types:


Feature	Fixed-Pressure Valves	Programmable Valves
Mechanism	Factory-set to drain at a specific pressure (e.g., low, medium, high).	Adjustable after surgery using an external magnetic device.
Flexibility	Non-adjustable without a repeat surgery to replace the valve.	Allows doctors to non-invasively change the pressure setting based on the patient's needs.
Appearance	Similar in appearance to programmable valves, a small disc.	Also appears as a small, disc-like device, often with a slightly different profile.
Treatment	Suitable for patients whose needs are consistent over time.	Ideal for patients whose pressure needs change due to growth, activity, or condition progression.

Natural Keyword Density: Living with a Shunt

Many people live full and active lives with a shunt system. Understanding what shunts look like, both internally and externally, helps patients and their families manage expectations. While a shunt is a permanent fixture, its presence is often understated and easily managed. Routine check-ups are essential to monitor the shunt's performance and ensure it functions correctly.

For more detailed information on living with a shunt and managing hydrocephalus, authoritative resources like the Hydrocephalus Association are invaluable. You can learn more by visiting their educational website here. Knowing what shunts look like and how they function helps demystify the process and empowers patients with knowledge about their condition.

Conclusion: A Hidden Lifeline

In summary, while the components of a shunt are complex and technologically advanced, their appearance from the outside is often quite subtle. The visible aspects include small scars from incisions, a palpable or slightly noticeable bump from the valve behind the ear, and potentially a fine line from the tubing under the skin. This sophisticated internal device is a quiet, hidden lifeline for many, enabling them to lead healthy and productive lives.

Frequently Asked Questions

You can typically feel the small, disc-like valve, which is usually located behind the ear or on the top of the head. The path of the thin, flexible tubing, called the catheter, can also be felt as a soft, cord-like line under the skin as it travels down the neck and torso.

A shunt valve is quite small, about the size of a quarter or smaller. Its exact size and shape depend on the manufacturer and the type of valve used (e.g., fixed-pressure vs. programmable), but it is designed to be as unobtrusive as possible.

A shunt can cause a small, visible or palpable lump where the valve and reservoir are located, especially if a person has a low body fat percentage or thin skin. In many cases, hair can hide the valve on the scalp. Some surgical techniques can minimize this bump.

For some people, especially those with less body fat, the tubing of the shunt can be seen or felt as a line just under the skin. This is most common along the neck, chest, and abdomen where the catheter is tunneled, but it is often very subtle.

Immediately after surgery, the implantation sites will have incisions covered by bandages. Once healed, small scars will be present at these locations. Swelling might be present initially but subsides over time, revealing the subtle contours of the valve and tubing.

While the basic components of shunts are the same for adults and children, the size and length of the catheters are adjusted. In children, a longer distal catheter may be used to accommodate future growth. The system's visibility may also differ due to varying body size and fat distribution.

You will not feel the adjustment itself. A neurosurgeon uses an external magnet to change the valve's pressure setting. This process is painless and does not involve additional surgery, but you may be instructed to avoid magnets for a period afterward.