A GJ tube (gastrojejunostomy tube) is a small, round device that sits flush against the skin of the abdomen or extends a few inches outward, depending on the style. It has two or three visible ports on the outside, each connecting to tubing that runs through the stomach and into the upper portion of the small intestine. If you’re trying to identify one, picture a flat silicone disc against the belly with short labeled ports sticking out, or a longer tube held in place by a bumper or balloon just inside the skin.
Low-Profile Button vs. Long Tube
GJ tubes come in two main styles, and they look quite different from each other. The low-profile version, often called a “button,” sits nearly flat against the abdomen. It looks like a small round cap or disc, roughly the size of a quarter to a half-dollar, with short ports that don’t dangle. When nothing is connected to it, the button barely protrudes from the skin, which is why it’s popular with active people, children, and anyone who finds a longer tube cumbersome or visible under clothing.
The traditional style is a longer tube that extends several inches outward from the abdomen. It’s held in place internally by a small inflated balloon or a flexible pigtail loop, and externally by a bumper or disc that rests against the skin. The tubing hangs outside the body and is usually taped or clipped to clothing or skin when not in use. Many patients and caregivers prefer the appearance of the low-profile button, though the longer tube can be easier for some medical teams to manage.
The Ports and What They Do
The most distinctive visual feature of a GJ tube is that it has multiple ports on the outside, each clearly labeled. You’ll typically see three:
- Gastric port: connects to the portion of the tube that opens into the stomach. This is used for venting air or draining stomach contents.
- Jejunal port: connects to the longer internal tube that reaches past the stomach and into the jejunum (the middle section of the small intestine). This is where formula or liquid nutrition goes in.
- Balloon port: a smaller valve used to inflate or deflate the tiny balloon that holds the tube in place inside the body. This port has a one-way valve so water stays inside once injected.
On low-profile buttons, these ports are short and capped when not in use. On longer tubes, they branch off from the main tube like a Y or T shape. The ports may be color-coded or labeled with text to help caregivers tell them apart quickly, which matters because feeding into the wrong port can cause problems.
Extension Sets and Connectors
If you see a GJ button with nothing attached, it looks like a simple disc with small capped openings. But during feeding or venting, an extension set clicks into the appropriate port. These extensions are thin, flexible tubes (usually 6 to 12 inches long) that connect the button to a syringe or feeding pump bag.
Modern extension sets use a connector system called ENFit, which has a twist-lock design that only fits enteral (feeding) devices. This prevents someone from accidentally connecting a feeding tube to an IV line. The ENFit tip is slightly wider than older connector styles and has a distinctive purple or orange ring, depending on the manufacturer. Extension sets come in two main types: a straight bolus connector for syringe feeds given over a few minutes, and a right-angle Y connector for slower continuous feeds delivered by a pump.
What’s Happening Inside the Body
From the outside, you only see the ports and the disc or bumper against the skin. But inside, the tube passes through a small surgically created opening in the abdominal wall (called a stoma), enters the stomach, and then continues as a thinner inner tube that threads through the lower stomach opening and into the jejunum. The jejunal portion of the tube can be anywhere from 15 to 45 centimeters long, depending on the patient’s size and anatomy.
The internal balloon, which you can’t see but can feel as slight resistance if you gently pull the tube, sits inside the stomach and prevents the device from sliding out. The stoma itself is typically just large enough to fit the tube snugly. In adults, tubes range from about 14 to 22 French in diameter (roughly 4.7 to 7.3 millimeters), with the stoma track matching that size. Stoma lengths, meaning the distance from the skin surface to the stomach wall, vary from 1.0 to 7.0 centimeters depending on body composition, so tubes are measured and fitted individually.
What a Healthy Stoma Looks Like
The skin around a well-healed GJ tube stoma should look similar to the surrounding skin, with the tube fitting snugly but not pulling or pressing too tightly. A small amount of crusty yellowish or greenish discharge around the base is normal and expected. The site is typically cleaned with mild soap and water.
Signs that something is off include redness spreading outward from the tube, swelling, tenderness, foul-smelling discharge, or fever. Pus or small pustules near the stoma suggest infection. Another common visual change is granulation tissue: pink, moist, bumpy tissue that grows around the stoma opening and looks a bit like a tiny cauliflower. Granulation tissue bleeds easily when touched or bumped. It’s not dangerous, but it can be uncomfortable, and it’s one of the most common issues caregivers notice when checking the site.
How GJ Tubes Differ From G Tubes and J Tubes
If you’re comparing devices, a G tube (gastrostomy tube) looks similar on the outside but has only two ports: one for feeding into the stomach and one for the balloon. A J tube (jejunostomy tube) enters the abdomen directly into the small intestine, bypassing the stomach entirely, and also has fewer ports.
The GJ tube is the hybrid. It enters through the stomach like a G tube but delivers nutrition further down the digestive tract like a J tube, which is why it needs the extra ports. This makes the GJ tube the bulkiest of the three at the skin surface, though the low-profile button version keeps that difference minimal. The reason someone gets a GJ instead of a simpler G tube is usually because their stomach doesn’t empty properly or they have severe reflux, so food needs to go directly into the small intestine while the stomach port remains available for venting trapped air and fluids.