Chapter 4 — Inspection

Inspection is the first hands-on step of the anorectal examination. It comes before any touching, and before any instrument is used. A careful look at the perianal skin and anal opening can reveal a great deal. It often points straight to the diagnosis, before palpation or digital examination even begins. This chapter explains how to inspect the anorectal region properly, and what the common findings mean.

4.1 Why Inspection Matters

Many anorectal conditions can be seen with the eye alone. A fissure, an external pile, a fistula opening, a perianal abscess, or a prolapse may all be visible on simple inspection. Skipping this step, or doing it too quickly, is one of the most common causes of missed or wrong diagnosis in anorectal practice.

Inspection also guides the rest of the examination. If a fissure is seen, the doctor knows something important. Digital rectal examination may need to be gentle. It may even need to wait until local anaesthetic has acted. If a fistula opening is seen, the doctor knows to look for its likely internal opening during the rest of the examination.

4.2 How to Inspect

Place the patient in the left lateral position, as described in Chapter 3. Use a good light. Gently part the buttocks with both hands. This brings the perianal skin and anal opening into full view. Ask the patient to relax as much as possible. A tense patient makes the anal opening pucker, and this can hide small findings.

Inspect the area at rest first. Then, ask the patient to strain gently, as if trying to pass stool. Straining can bring a prolapse, internal piles, or a hidden fistula opening into view. These findings are completely invisible at rest.

4.3 What to Look For

A systematic inspection covers the following points, in order:

Skin condition — colour, any rash, excoriation, or scarring from old surgery. Swellings — external piles, skin tags, abscess, or other lumps. Fissure — a small tear in the skin, usually in the midline, most often at the back (posterior midline). Fistula openings — small openings in the skin, which may discharge pus, blood, or mucus. Prolapse — any tissue that comes out of the anus, either on its own or with straining. Discharge or soiling — mucus, pus, or stool staining the skin or underclothes. Scars — from earlier surgery, injury, or childbirth. The anal opening itself — its shape, and whether it is patent (open) or narrowed.

4.4 Inspecting for a Fissure

A fissure often causes the anal opening to look slightly open. The muscle around it is often tight, and in spasm. A small skin tag, called a sentinel pile, is sometimes seen just below the fissure. Gently separating the anal margin, without causing pain, can bring the tear itself into view. If the patient is in severe pain, do this step with great care. Forceful separation can cause needless distress.

4.5 Inspecting for Piles

External piles are seen as soft, bluish or skin-coloured swellings at the anal margin. They may be single or multiple. Internal piles are usually not visible at rest, since they lie above the dentate line, inside the anal canal. On straining, however, internal piles of a higher degree may come down. They then become visible as reddish-purple, grape-like swellings.

4.6 Inspecting for Fistula-in-Ano

A fistula opening appears as a small, red, raised punctum on the perianal skin. Gentle pressure around it may express a drop of pus or serous fluid. The position of the external opening, relative to the anus, gives a useful early clue. This clue points to the likely path of the fistula tract. This point will be explained fully in the chapter on fistula-in-ano.

4.7 Inspecting for Prolapse

A rectal prolapse appears as a red, moist, ring-like mass. It comes out of the anus, usually with straining. It is important to note whether the prolapse involves the full thickness of the rectal wall. This type is seen as circular folds. Or the prolapse may involve only the mucosa, seen as radial folds. This distinction matters greatly for later management. It is explained further in the chapter on rectal prolapse.

4.8 Inspecting the Natal Cleft

While the patient is in position, also look at the natal cleft. This is the groove between the buttocks, above the anus. Check this area for a pilonidal sinus. It is seen as one or more small pits or openings in the midline, sometimes with a tuft of hair visible at the opening. Pilonidal disease is easily missed if the examiner looks only at the anus itself, and skips the natal cleft.

4.9 Recording the Findings

Anorectal findings are best recorded using a clock-face description. Always state the position the patient was in during examination. For example, "a fissure at 6 o'clock" gives a clear, exact location. Any other doctor can understand it at a glance. Always state clearly which position the patient was in when the clock-face was assigned. This detail can otherwise cause confusion between different examiners.

4.10 Why This Chapter Matters

Inspection takes only a minute. But it often gives the single most useful clue in the whole examination. A doctor who inspects carefully, in good light, both at rest and on straining, will reach the correct diagnosis far more often. This is far better than moving straight to palpation or instruments. The next chapter builds on this with palpation and digital rectal examination.