Stoma Siting: How Your Stoma Position Is Chosen

Stoma siting is the preoperative process of choosing and marking where a colostomy, ileostomy or urostomy will sit on the abdomen. A trained stoma care nurse assesses you sitting, standing and lying so the stoma lies on flat, visible, healthy skin — usually within the rectus muscle and clear of scars, creases and the belt line. The goal is a site you can see and care for independently.

Why the position of a stoma matters

A well-chosen site makes pouching simpler, reduces leaks and sore skin, and supports clothing choices and independence. A site in a crease, under a fold, on a bony ridge, or out of sight is a common reason for leakage and loss of confidence. Preoperative marking is widely regarded as best practice because the team can plan around your body in everyday postures, not only the flattened abdomen of a patient under anaesthetic.

Large randomised trials are lacking, but surgical and nursing bodies recommend that a trained stoma care nurse mark the abdomen before elective surgery whenever a stoma is possible. Even if the surgeon hopes to avoid a stoma, a contingency mark is standard so a stoma is not placed at random.

Who chooses and marks the site

In the United Kingdom and in most specialist centres, a stoma care nurse (or stoma nurse specialist) leads siting, working with the operating surgeon. The nurse is trained in abdominal assessment and in the practicalities of living with a stoma. You should be an active partner: the site has to work for your eyesight, dexterity, job, sport, faith-related dress and any disability, not only for surgical access.

Your surgeon remains responsible for the operation, for whether a stoma is formed, and for any change of plan once the abdomen is open. Blood supply, disease and remaining bowel can force a different location. The mark is a negotiated recommendation, not a promise. Discuss worries about position or self-care with your stoma care nurse or clinician before the day of surgery.

How the assessment is done

The appointment is usually 20–40 minutes in clinic or on the ward. Wear or bring typical clothes, including a belt, brace or religious garment if you use one. The nurse inspects the whole abdomen, notes scars, hernias, skin disease and your natural waist, then watches how the skin folds when you move.

Sitting, standing, lying and bending

The abdomen changes shape with posture. A site that looks ideal lying flat may vanish into a crease when you sit, which is how most people empty a pouch. The nurse assesses you lying down (the theatre position), sitting — including on the bed edge or in your own wheelchair — standing, and, if relevant, bending or reaching.

You may be asked to lean forward or cough so hidden creases appear. Wheelchair users should be assessed in the chair; the stoma is often placed higher so it stays visible and clear of the lap and waistband.

Anatomical landmarks

Whenever anatomy allows, the stoma is brought through the rectus abdominis muscle. That tunnel is thought to support the bowel or conduit and may reduce parastomal hernia risk compared with a site outside the muscle. Hernias can still occur, and evidence on the protective effect is mixed, so this is a guide rather than a guarantee.

The nurse looks for a circle of intact, reasonably flat skin large enough for a pouching system, clear of the umbilicus, the hip bone and lower ribs, old scars and keyhole ports, deep folds, the belt line, breast tissue or an abdominal fold that would hide the stoma, and irradiated or broken skin.

Side depends on the operation. An end colostomy after rectal surgery is often on the left; an ileostomy or urostomy (ileal conduit) is often on the right. Previous surgery can override this. If two stomas are planned, they are separated so each pouch has its own field of healthy skin.

Everyday life, work and clothing

A tidy anatomical site that sits under a tool belt, lumbar brace or tight waistband will fail in daily life. Tell the nurse what you actually wear, whether you lift, drive or carry instruments on the torso, any pregnancy plans, and limits of vision, grip or shoulder reach. You may hold a sample pouch over a proposed mark to judge bulk under a shirt. That is an educational check, not product fitting.

Special situations

Emergency surgery

In unplanned operations for obstruction, perforation or trauma there may be no time to assess you sitting and standing. The surgeon then chooses the best available site while you are under anaesthetic. That is sometimes unavoidable. Stomas formed without preoperative marking are associated with more fitting difficulties. If you wake with a stoma that is hard to see or pouch, ask for an early stoma care nurse review. Moving a stoma is further surgery and is not done lightly, but technique, custom patterns and support garments can often help.

Body shape, disability and previous surgery

After major weight change, pregnancy, or with a large abdominal apron, usable flat skin may sit well above the usual lower-quadrant position. A higher site you can see in a mirror is usually safer than a textbook site you cannot reach. Scoliosis, contractures, mesh and existing stomas all change the map. The nurse and surgeon should explain any compromise in plain language.

Different types of stoma

Principles are the same for colostomy, ileostomy and urostomy: visibility, a flat landing zone and healthy abdominal wall. Ileostomy and urostomy output is more liquid and more irritating to skin, so a site that allows a complete seal is especially important. A loop stoma still needs the same skin assessment. If a stoma might be temporary, it is still worth siting well: temporary can last many months.

After the mark is made

The point is drawn with a surgical skin marker. Some services cover it with a small dressing; others ask you to keep the area dry. If the ink fades, contact the stoma care team rather than redrawing it yourself — an amateur mark can mislead theatre staff. If it has vanished on the day, they will reassess.

Ask for a second look if you lose or gain a substantial amount of weight, become pregnant, start using a wheelchair, or have further abdominal surgery before the operating day. You should leave knowing why that spot was chosen and how to reach the stoma care nurse afterwards. Leaflets and a pouch demonstration are usual, but they do not replace personal advice from your own team.

The bottom line

Stoma siting matches surgical anatomy with the way your abdomen moves, folds and is clothed. A trained stoma care nurse marks a visible, flat site, ideally through the rectus muscle and clear of scars, bones and the waistline, while you sit, stand and lie down. Emergency operations sometimes skip this step. Speak to your stoma care nurse or clinician if the mark fades, your body changes, or you are unsure the proposed position will work for you.