Inspection tells the doctor what can be seen. Palpation and digital rectal examination tell the doctor what can be felt. Together, these two steps complete the local examination. They often confirm, or correct, what inspection first suggested. This chapter covers both. It explains gentle palpation of the perianal skin. It also explains the digital rectal examination, or DRE. This is one of the most important steps in all of surgery. It is also one of the most often skipped.
5.1 Why This Step Cannot Be Skipped
Many important anorectal conditions cannot be seen from outside at all. A low rectal growth needs a finger to find it. So does the internal opening of a fistula. So does the tone of the sphincter muscle. So does tenderness deep to the skin. Doctors sometimes avoid the digital rectal examination. This may be because the patient is anxious, or because time is short. This is a serious mistake. A missed rectal cancer, found only because a doctor skipped this simple step, is one of the most common causes of delayed diagnosis in surgery.
A well-known teaching saying puts it simply: "If you do not put your finger in, you may put your foot in it." This means something important. Skipping the examination can lead to a missed diagnosis. It can lead to real harm to the patient.
5.2 Palpation of the Perianal Area
Before inserting a finger into the anal canal, first feel the skin around the anus. Use gentle fingertip pressure. This step is called palpation.
Feel for tenderness. A tender, hot, swollen area suggests an abscess.
Feel for induration — a firm, thickened area under the skin, which can suggest a deeper fistula tract or a chronic abscess.
Feel for a fluctuant swelling. A soft, fluid-filled swelling that moves under the finger suggests pus collected under the skin.
Note any lump, and its size, shape, and consistency (soft, firm, or hard).
The area may be very tender. There may be a hot, fluctuant swelling. In these cases, a full digital examination may need to wait. Forcing a finger into an acutely painful, infected area causes needless pain. It can even spread infection. In such cases, examination under anaesthesia may be needed instead. This will be explained further in the chapter on perianal abscess.
5.3 Preparing for Digital Rectal Examination
Once palpation is complete, prepare for the digital rectal examination itself.
Explain to the patient, in simple words, what you are about to do.
Use a well-fitting glove.
Apply a generous amount of water-based lubricant to the gloved index finger.
Warn the patient that they will feel pressure, and possibly an urge to pass stool. Reassure them that this feeling is normal, and that nothing will actually happen.
Ask the patient to relax, and to breathe slowly and deeply.
A well-lubricated finger, inserted slowly, causes very little discomfort in most patients. A dry, hurried examination is a common and avoidable cause of pain.
5.4 Performing the Examination
Place the pad of the gloved index finger gently against the anal opening. Ask the patient to bear down slightly, as if passing stool. This relaxes the external sphincter, and makes entry easier. As the sphincter relaxes, gently and slowly advance the finger into the anal canal. Follow its natural direction, toward the umbilicus.
Once the finger is fully inside, pause for a moment. This gives the sphincter time to relax fully around the finger. It makes the rest of the examination much more comfortable for the patient.
5.5 What to Assess
A systematic digital rectal examination checks the following, in order:
Sphincter tone — Ask the patient to squeeze around the finger. A normal, firm squeeze suggests a healthy external sphincter. A weak or absent squeeze may point toward nerve damage or old sphincter injury.
Resting tone — Note the tightness of the canal at rest, before asking the patient to squeeze. A very tight canal, with sharp pain on gentle pressure, suggests a fissure. A very lax canal may point toward sphincter weakness.
Tenderness — Note any specific point of tenderness, and its position on the clock face.
Masses — Feel all the way around the canal and lower rectum for any lump. Note its size and its surface, smooth or irregular. Note whether it is fixed to surrounding tissue, or freely movable.
The prostate, in men — Felt through the front wall of the rectum. Note its size and surface. Note any hardness or nodule, which needs further urological assessment.
The cervix, in women — Sometimes felt through the front wall as a firm, rounded structure. This is a normal finding, and should not be mistaken for a mass.
Blood, mucus, or pus on the withdrawn glove — Always inspect the glove itself after withdrawing the finger. This is a simple step that is very easy to forget. It can reveal bleeding that was not visible from outside.
5.6 Special Situations
In a patient with a very painful fissure, the digital rectal examination itself may need to be deferred. It can instead be done only after the application of local anaesthetic gel and a short wait. In such cases, do not force the examination. A gentle attempt is far better than causing unnecessary suffering. Honest documentation, stating that a full examination could not be completed due to pain, is also far better.
In a very anxious patient, a calm explanation and a slow, unhurried approach usually allow the examination to be completed. Rarely, examination under anaesthesia is needed. This is particularly true in children, or in adults who cannot tolerate the examination despite reassurance.
5.7 Common Mistakes to Avoid
Inserting the finger too quickly, without waiting for the sphincter to relax. This is the single most common cause of an unnecessarily painful examination.
Using too little lubricant.
Stopping the examination as soon as the finger is inside, without systematically checking tone, tenderness, and masses in order.
Forgetting to check the withdrawn glove for blood, mucus, or pus.
Assuming a normal digital rectal examination rules out cancer. Many rectal growths lie higher up, beyond the reach of the finger. These still need proctoscopy, or further imaging, if red flag symptoms are present.
5.8 Recording the Findings
As with inspection, record digital rectal examination findings using the clock-face method. Always state the position the patient was examined in. For example: "tender fibrous cord felt at 6 o'clock, consistent with a chronic fissure." This gives a clear, exact record that any other doctor can understand.
5.9 Why This Chapter Matters
The digital rectal examination is simple and quick. It needs no equipment. Yet it remains one of the most valuable steps in the whole clinical examination. A doctor who performs it gently, and every time it is indicated, will catch serious disease early. Such a doctor will also reassure anxious patients with a normal finding. The next chapter builds on this with proctoscopy and sigmoidoscopy. These allow the doctor to see directly what has so far only been felt.